Breast cancer is the second most common cancer in the world. Despite advances in therapies, the mechanisms of resistance remain the underlying cause of morbidity and mortality. Lipoic acid (LA) is an antioxidant and essential cofactor in oxidative metabolism. Its potential therapeutic effects have been well documented, but its mechanisms of action (MOA) are not fully understood.The aim of this study is to validate the inhibitory LA effect on the proliferation of various breast cancer cell lines and to investigate the MOA that may be involved in this process. We tested LA effects by ex vivo studies on fresh human mammary tumour samples.We demonstrate that LA inhibits the proliferation and Akt and ERK signalling pathways of several breast cancer cells. While searching for upstream dysregulations, we discovered the loss of expression of IGF-1R upon exposure to LA. This decrease is due to the downregulation of the convertase, furin, which is implicated in the maturation of IGF-1R. Moreover, ex vivo studies on human tumour samples showed that LA significantly decreases the expression of the proliferation marker Ki67.LA exerts its anti-proliferative effect by inhibiting the maturation of IGF-1R via the downregulation of furin. It is an essential coenzyme for mitochondrial enzymes, such as pyruvate dehydrogenase and α-ketoglutarate dehydrogenase.It is classified under several molecular subtypes, according to the presence or absence of oestrogen receptor α (ERα). This classification is important for disease prognosis, as well as for determining and providing an adequate therapy.9 In breast cancer, it has been demonstrated that the expression of the insulin-like growth factor-1 receptor (IGF-1R) increases in both ER-positive (ER+) and ER-negative (ER–) breast cancers and plays an oncogenic role.10 Moreover, many studies have shown the ability of IGF-1R to induce mammary tumour growth and metastases.13 Activation of IGF-1R in turn activates multiple signal transduction cascades, including PI3K/Akt and MAPK/ERK pathways,16 contributing to the promotion of breast cancer metastasis.Despite advances in chemotherapy, hormonotherapy and targeted therapy in combination or not with surgery, the mechanisms of resistance remain the underlying cause of morbidity and mortality.17 Once Akt is activated, it stimulates the mammalian target of the rapamycin complex (mTORC1), which is a key regulator of cellular growth. In addition, the mTOR pathway is indirectly downregulated by activated AMPK, which is an energy sensor implicated in the regulation of protein and lipid metabolism in response to changes in fuel availability.18 Moreover, activation of AMPK is known to have anticancer effects in various cancer models, such as breast, colon and lung cancers.19 Activation of the pathways described above by IGF signalling requires the cleavage of pro-IGF-1R into its mature form. This maturation process is ensured by members of the pro-protein convertase family (PCs), including furin . The latter is highly expressed in many types of cancers, including breast cancer, and was shown to promote the cancer cell proliferation, migration and invasion.20Indeed, both PI3K/Akt and MAPK/ERK pathways have been shown to be involved in various processes, such as cancer cell proliferation, migration and metabolism.25 However, the precise molecular mechanisms by which LA elicits its anticancer properties remain largely unknown yet. In this study, we deciphered, for the first time, how LA inhibits the proliferation of breast cancer cells. As such, we investigated the inhibitory role of LA on the main proliferative pathways and on the maturation of their upstream effectors, notably IGF-1R. Our in vitro results demonstrate that LA inhibits IGF-1R maturation, and these results are supported by ex vivo findings.In breast cancer, several studies demonstrated an anti-proliferative effect of LA.LA was purchased from Sigma (Sigma). A stock solution was prepared by dissolving LA in absolute ethanol and stocked at −20 °C. LA was diluted in culture medium for in vitro and ex vivo experiments.26ERα+ cells lines  and ERα– cell lines  were obtained from the ATCC. All of the cell lines were maintained at 37 °C in the appropriate medium supplemented with 10% foetal bovine serum, 1% non-essential amino acid and 2% penicillin/streptomycin. All cell lines were regularly tested for mycoplasma contamination. We also used frozen tumours from human breast cancer-derived xenografts (PDX) from Dr. Marangoni. HBCc-12A- (ERα–) and HBCx-3-expressing (ERα+ ) cell lines were established from the human breast cancer xenografts as described by Marangoni et al.furin-specific siRNAs from ThermoFisher Scientific (ambion s9988 and s9987) siRNA furin 1: sens: 5′-GGGCCUUCAUGACAACUCATT-3′; anti sens: UGAGUUGUCAUGAAGGCCCAG; siRNA furin 2: sens: GGUGGAAAAUGGACUGGCUTT; anti sens: AGCCAGUCCAUUUUCCACCTT; the scramble siRNA (Eurogentec) (20 nM) was transfected into MCF‐7 and MDA-MB-231 cells using the lipofectamine 2000 reagent according to the manufacturer’s instructions (Invitrogen).For knockdown experiments, Cell proliferation was assayed using an IncuCyte® ZOOM Live-Cell Analysis System , by collecting real-time data of cell confluence. Cells were seeded onto 96-well plates (5000 cells/well) and left to attach for 24 h. The cells were then treated with different concentrations of LA or absolute ethanol. Cell proliferation data were obtained by the cell confluence increment in each of the treatments, and expressed as percentage relative to that of control cells. Each sample was tested in triplicate.3VO4 and 1 mM β-glycerophosphate). Cell lysates were cleared by centrifugation , and protein concentration was determined by the Bradford method (Bio-Rad protein Assay). Proteins samples were separated on SDS-PAGE, and membranes were incubated with primary antibodies overnight at 4 °C on a shaker with the following primary antibodies: anti-IGF-1R , anti-IR-α , anti-EGFR , anti-furin (Proteintech), anti-Akt and anti-pAkt , anti-ERK and anti-pERK , anti-S6 and anti-pS6 , anti-S6K1 and anti-pS6K1 , anti-AMPK and anti-pAMPK  and anti-Tubulin (Sigma). Membranes were washed with TBS-Tween, and incubated with anti-rabbit or anti-mouse secondary antibodies. Detection was carried out using ECL Prime reagent .Cells were lysed using RIPA buffer  supplemented with protease inhibitor tablets  and phosphatase inhibitors  using SsoAdvanced™ Universal SYBR® Green Supermix according to the manufacturer’s instructions. The mRNA level was normalised to 28S using Livak’s method (2−(ΔΔCq)) method. RT-qPCR conditions were as follows: 1 activation step for 5 min at 94 °C, 35 cycles of denaturing at 94 °C for 15 s, primer annealing at 59 °C for 45 s and primer extension at 72 °C for 2 min and a final extension at 72 °C for 5 min.The total RNA was isolated using TRIzol (Invitrogen) according to the manufacturer’s instructions. RNA was reverse transcribed to complementary DNA (cDNA) using SuperScript™ II Reverse Transcriptase (Life Technologies). The primers are listed as follows: In total, 80,000 MCF7 cells were seeded onto glass coverslips and incubated with LA for several time points (24 and 48 h). The cells were fixed in methanol for 2 min and washed once with cold PBS. We used rabbit anti-IGF-1R as a primary antibody , and fluorescein isothiocyanate (FITC)-conjugated goat anti-rabbit IgG (Jackson ImmunoResearch) as a secondary antibody.Fresh human mammary samples were obtained from chemotherapy-naive patients with invasive carcinoma after surgical resection at the Centre Léon Bérard . As required by the French Committee for the Protection of Persons, informed consent was obtained from patients to use their surgical specimens and clinicopathological data for research purposes, and the local ethics committee approved the protocols. Nine tumours were cut into thin slices of 250 µm using a vibratome (HM 650 V Microm) and incubated for 48 h with or without 2 mM of LA Table . Slices Immunohistochemistry was performed on 4-mm-thick sections of formalin-fixed, paraffin-embedded and heat-treated  tissues (DakoCytomation). Sections were stained with haematoxylin–eosin–safran, and for immunohistochemistry detection, the primary antibodies used were anti-IGF-1R  and anti-Ki67 . Diaminobenzidine was used as chromogen. Images were acquired using a Zeiss Axiovert. The whole slide was scanned automatically with the Histolab 6.2.0 MICROVISION Instrument system.t test was used for statistical analysis. A P value of < 0.05 was considered statistically significant. *P < 0.05; **P < 0.01; ***P < 0.001. The graph artwork was created using Microsoft office Excel 2010 and GraphPad prism 6.Data are presented as mean ± SEM of three independent experiments. Unpaired two-tailed Student’s To investigate the effect of LA on breast cancer cell proliferation, we treated the cells with MCF7, and MDA-MB-231 breast cancer cell lines were treated with different concentrations of LA and monitored their viability using the IncuCyte real-time imaging system. We first studied its role on ERα+ cell lines . LA treatment at 0.5 mM was able to reduce the proliferation of Cama1 cell line. However, this concentration of LA had little effect on MCF7 and HBCx-3 cell lines, while increasing concentrations totally inhibited cell proliferation  form upon LA treatment in a time- and concentration-dependent manner. These results were confirmed by immunofluorescence, highlighting a change in the localisation of IGF-1R from the plasma membrane to the cytoplasm. Herein, the cytoplasm localisation of IGF-1R is an indication of its deactivation.48 However, it is not always the case. In this context, it has long been recognised that ligand binding at the plasma membrane induces internalisation of activated IGF-1R.49To gain further insight into these mechanisms, we studied the expression of the tyrosine kinase receptor, IGF-1R, which is an attractive therapeutic target in breast cancer, in response to LA treatment. Of note, the correlation between IGF-1R overexpression and cancer development, as well as the role of its downstream signalling cascade, such as activation of the PI3K/Akt pathway, in the promotion of proliferation of breast cancer cell lines, have been reported in several studies.31 IGF-1R maturation is processed by the pro-protein convertase furin. This enzyme is enriched in the Golgi, and this is where cleavage of IGF-1R pro-receptor into an active form is thought to occur. Moreover, furin is also involved in processing of IGF 1/2.50 It is well known that furin is overexpressed in cancer, and it is considered as a tumour progression marker or as a prognostic factor.51 For this reason, researchers were interested in determining its role in cancer progression and promotion. Accordingly, several studies have considered furin as an effective anticancer target.53 Indeed, we herein demonstrated that LA reduces furin mRNA levels, leading to a decrease in its protein expression.Furthermore, based on previous studies,54 Of note, numerous in vitro and in vivo studies have demonstrated the correlation between IR overexpression and malignancy in several cancer models, including breast cancer.55 The two structurally different isoforms of IR, IR-α and IR-β, are overexpressed in many cancers.56 IR-α is the main isoform that plays an important role in cancer cell stemness, in tumour progression and in resistance to IGF-1R-targeted therapies . For these reasons, we also studied the expression of IR upon LA treatment. Interestingly, our results showed that IR-α is abolished in favour of the immature form (pro-IR) upon LA treatment (1 and 2 mM) in our breast cancer cell lines. Collectively, our results show that LA inhibits the IGF-1R and IR-α maturation by reducing furin expression. This work reveals the important role of LA in cancer treatment, thanks to its dual inhibition of the IGF-1R/IR network, which is a serious obstacle to treatment efficacy.52In addition, IGF-1R is highly homologous to another tyrosine kinase receptor, namely the insulin receptor (IR).57 Based on these data and our results, we can hypothesise that the downregulation of furin upon LA treatment could induce the accumulation of the pro-ADAM17 (inactive form), which then could inhibit the release of EGFR ligands and their binding on their receptor. These events could induce EGFR internalisation and degradation.Moreover, our results have shown that LA reduces the EGFR expression with appearance of a doublet by western blots Fig. . Of noteThe ex vivo model presented herein enabled us to replicate the microenvironment of intact breast tumour tissues. This approach maintains specific interactions between tumour cells and the surrounding normal tissue components, and supplies a powerful and reproducible tool to study the response of fresh individual tumours to anticancer drugs. We tested a series of nine human primary breast tumours in this ex vivo assay. Our results showed that five tumours revealed a significant decrease in Ki67 levels in response to LA. Moreover, among these nine tumours, only three tumours expressed IGF-1R at the basal level, and this expression decreased upon LA treatment. Thus, these results confirm the beneficial effects of LA on breast cancer cells in their microenvironment.Taken together, we herein show that LA inhibits the proliferation of various ERα+ and ERα− breast cancer cell lines in vitro and ex vivo by inhibiting the maturation of IGF-1R Fig. . This insupplementary data


In contrast, elevated sound speed was significantly associated with breast cancer risk in a dose–response fashion . The OR trend for sound speed was statistically significantly different from that observed for MPD (p = 0.005). These findings suggest that whole breast sound speed may be more strongly associated with breast cancer risk than MPD and offer future opportunities for refining the magnitude and precision of risk associations in larger, population-based studies, including women younger than usual screening ages.Mammographic percent density (MPD) is an independent risk factor for developing breast cancer, but its inclusion in clinical risk models provides only modest improvements in individualized risk prediction, and MPD is not typically assessed in younger women because of ionizing radiation concerns. Previous studies have shown that tissue sound speed, derived from whole breast ultrasound tomography (UST), a non-ionizing modality, is a potential surrogate marker of breast density, but prior to this study, sound speed has not been directly linked to breast cancer risk. To that end, we explored the relation of sound speed and MPD with breast cancer risk in a case-control study, including 61 cases with recent breast cancer diagnoses and a comparison group of 165 women, frequency matched to cases on age, race, and menopausal status, and with a recent negative mammogram and no personal history of breast cancer. Multivariable odds ratios (ORs) and 95% confidence intervals (CIs) were estimated for the relation of quartiles of MPD and sound speed with breast cancer risk adjusted for matching factors. Elevated MPD was associated with increased breast cancer risk, although the trend did not reach statistical significance (OR per quartile = 1.27, 95% CI: 0.95, 1.70; p Mammographic percent density (MPD) is a strong breast cancer risk factor that typically confers a three—to fivefold elevation in risk for the highest versus lowest levels of density . Given tAll current methods of MPD measurement (including tomosynthesis) are based on one or more two-dimensional projected areas of the breast rather than the full uncompressed volumes of the breast. Attempts to measure volumetric breast density (BD) in mammograms ,6 have nA large number of studies have shown that various MRI sequences, with and without contrast, can be used to characterize BD, and comparisons with mammographic percent density (MPD) have shown a high degree of correlation ,15,16,17The potential gains in risk prediction that might be realized by using alternative measures of BD obtained through emerging non-ionizing technologies have not been fully explored. The impetus for such technologies is to advance risk stratification, and thereby improve breast cancer risk assessment and monitoring and facilitate research into the etiology and prevention of the disease. Such activities will push early detection strategies toward the long-term goal of ‘risk-based’ screening in which both the frequency and type of screening are chosen based on the level of risk .Previously, we proposed a new analog to MPD based on speed of sound measurements of breast tissue derived from whole breast ultrasound tomography (UST) ,27,28,29n = 15 high-risk patients referred to tamoxifen for chemoprevention were excluded, and the analysis was restricted to the baseline pre-treatment UST scans and mammograms of the unaffected breast of women with unilateral breast cancer (n = 61 cases) and women with no personal history of breast cancer (n = 165 controls).The study population was part of a larger observational study, the Ultrasound Study of Tamoxifen, which enrolled 76 patients referred for tamoxifen treatment for clinical indications and a matched comparison group of 165 women with screen negative mammograms, aged 30–70 years, at the Barbara Ann Karmanos Cancer Institute (KCI) and Henry Ford Health Systems (HFHS) in Detroit, MI from 2011 to 2014 ,29. For Cases were identified at KCI and HFHS based on a recent diagnosis of breast cancer after routine screening. Exclusion criteria were (1) pregnant; (2) lactating; (3) with active skin infections or open chest wounds because of the open interface with the water in the imaging tank; (4) breast size more than 22 cm in diameter (limit of the size of the ring ultrasound transducer); and (5) over 350 lb of weight . Furthermore, we excluded women who had (6) bilateral synchronous breast cancer in that a breast without radiological signs of cancer would not have been available for analysis; and (7) breast implants or reduction mammoplasty.To be eligible for the control group, a screening mammogram obtained at KCI or HFHS with the recommendation to continue routine screening  diagnostic score of “1” or “2”) was first identified for the woman. In addition, eligible controls had no personal history of breast cancer and had not received medications or radiation for any type of cancer, were not taking tamoxifen or raloxifene to lower breast cancer risk, and had none of the exclusion criteria given above for cases. We also excluded women who were currently taking endogenous hormones , since these medications may modulate breast density. Potential controls were invited to undergo UST and were frequency matched to the case group on age, race, and menopausal status. Since we compared each participant’s mammogram to her UST scans, we attempted to schedule controls for their UST visit within approximately one month of the screen-negative mammogram date. A one-month window was justified on the basis that breast density declines with age at a rate of 1%–2% per year, which translates to <0.2% per month—well below our uncertainty of BD measurement by either mammography or UST.At the time of the UST scan, health information was collected from cases and controls via a standard health history questionnaire administered by a research nurse, including demographics, reproductive history and menopausal status. Measured weight and height were also collected. All procedures were performed under Institutional Review Board-approved protocols at the KCI, HFHS, and National Cancer Institute, with informed consent obtained from all patients.Full-field digital mammograms were obtained at KCI or HFHS. Both sites are certified by the American College of Radiology’s Mammography Accreditation Program and maintain image quality control according to the Mammography Quality Standards Act. All UST scans were performed at KCI with the SoftVue system , manufacIn cases, BD was measured pre-treatment in the contralateral breast to avoid the potential influences of tumor-related changes on MPD or sound speed. For controls, we randomly selected a breast for both mammographic and UST assessment, since concurrent mammographic density measurements of left and right breasts from the same individuals have been reported to be highly correlated and predictive of risk irrespective of side  . Observe2) and total breast area (cm2). MPD was calculated as the dense area divided by the total breast area multiplied by 100. The area-based MPD measures estimated from Cumulus have been strongly and consistently associated with elevated breast cancer risk in numerous epidemiologic studies [Craniocaudal (CC) mammographic views were analyzed using Cumulus , a compu studies . A singl studies . A reevaCalculate the volume of the breast, V, through a direct pixel count using previously developed automated scripts.Calculate the volume averaged sound speed (VASS) for each stack by summing up all the pixel values and dividing by the volume determined above using our automated script.Apply this calculation to image stacks  from all cases and controls.Data were reconstructed from the raw data collected by UST and output as DICOM images which were viewed on a standard display workstation . The volA previous reproducibility study in a subset of 22 participants demonstrated that UST sound speed estimates were highly reliable (ICC = 93.4%) .2) did not differ by case-control status, in sensitivity analyses, we additionally adjusted for BMI given its strong inverse association with BD.Percentiles of all variables were defined based on their distribution among controls. Associations between participant characteristics and quartiles of MPD or VASS were estimated among controls using chi-square or Fisher’s exact tests for categorical variables and the Kruskal–Wallis test for continuous variables. Odds ratios (ORs) and 95% confidence intervals (CIs) for the association between quartiles of MPD and VASS with breast cancer risk were estimated using logistic regression, adjusting for matching factors , race , menopausal status . Participant characteristics were considered as potential confounding factors in multivariable logistic regression models. In sensitivity analyses, we adjusted models mutually for MPD and VASS. Although body mass index ; statistical tests were two-sided, and p-values < 0.05 were considered statistically significant.We compared the strength of association between MPD and VASS with breast cancer risk using a bootstrap approach as follows. First, we resampled the same numbers of cases and controls as in the original dataset randomly with replacement. We then fit two logistic regression models, one with quartiles of MPD and the other one with quartiles of VASS as the exposure and estimated the respective log ORs. This was repeated 1000 times. Then, we computed the square of the difference of the log ORs based on the original dataset and divided that difference by the sum of the variances of the log ORs minus two times their covariance. The estimate of the variance covariance matrix of the estimates was the empirical bootstrap variance covariance matrix. We compared that ratio to a Chi-square distribution with one degree of freedom to obtain a 2). Median (range) time between the mammogram and UST scan was 4.1  months for cases and 1.2  months for controls.The epidemiological attributes of the cases and controls are summarized in p < 0.0001), as well as with each other (p < 0.0001). As we have previously shown among these controls, continuous VASS measures were also strongly and positively correlated with MPD  [The relationship of participant characteristics among controls with quartiles of VASS and MPD are shown in < 0.001) .The distributions of MPD and VASS, categorized in quartiles determined based upon the control distribution, by case-control status are shown in ptrend = 0.10) (ptrend = 0.0003) ; ptrend < 0.0001  . In cont 0.0003) . Finding< 0.0001 .p = 0.005). With mutual adjustment, the risk association for MPD was null, whereas the risk association for SS remained statistically significantly elevated, both with and without adjustment for BMI (Furthermore, using a bootstrap approach, we determined that the OR trend for sound speed shown in  for BMI .The goal of this study was to explore VASS as a potential new UST-based risk factor for breast cancer. Herein, we observed that while both elevated MPD and UST breast sound speed were associated with increased breast cancer risk, the magnitude of the risk association was stronger for UST as compared with MPD in this case-control study. Having dense breasts is very common ; thus, eThe lack of statistical significance for the OR trend for MPD is not necessarily surprising given that BMI in our study population tended to be elevated and the BD distribution skewed toward lower breast densities. Based on a post hoc power calculation, we had 80% power to detect an OR associated with elevated MPD of 3.2 or higher comparing the highest to the lowest MPD quartile, for the given sample sizes of 61 cases and 165 controls. While the sample size, demographics, and skewed density distribution limit the generalizability of these findings to the larger US population, the assessment of the performance of VASS relative to MPD is valid for this particular population. The fact that strong ORs are obtained for VASS, despite operating within a narrow BD range skewed toward lower breast densities, suggests that a larger magnitude of association associated with elevated VASS may be observed in the general population of women, where dense breasts are more prevalent. Furthermore, although our breast cancer cases were patients referred to tamoxifen for clinical indications, all breast imaging was obtained prior to treatment initiation, and prior research suggests that elevated MPD is related to increased risk of both ER+ and ER− breast cancers , giving Our results suggest that VASS has a stronger dependence on breast cancer risk than MPD and therefore has the potential to increase precision in standard risk models. Current methods of measuring BD based on mammography, either by radiologist’s estimation or computer-assisted measurement, limit the risk stratification achievable by the inclusion of BD in risk models . PotentiThe results of this study have several important implications. First, findings will inform future longitudinal studies aimed at establishing temporal relationships between UST breast sound speed and breast cancer risk, ultimately facilitating the incorporation of validated UST-derived parameters into evolving risk models. Genome-wide association studies in young women are in progress to define the genetic susceptibility loci associated with BD and breast cancer risk, and UST may allow the further characterization of this phenotype in larger numbers of young women at relatively low cost. Research to examine the effects of potential preventive interventions for breast cancer would also become possible at earlier ages and at multiple times points with UST , since tIn conclusion, this exploratory case-control study showed that increasing quartiles of whole breast volume averaged sound speed were consistently and more strongly associated with increasing breast cancer risk than quartiles of mammographic percent density. These findings suggest future opportunities for refining the magnitude and precision of UST–breast cancer risk associations, using a non-ionizing imaging modality, in larger population-based studies.


Prior studies reported the association of reproductive factors with breast cancer (BC), but the evidence is inconsistent. We conducted a pooled analysis of nine cohort studies in Japan to evaluate the impact of six reproductive factors  on BC incidence. We conducted analyses according to menopausal status at the baseline or at the diagnosis. Hazard ratio (HR) and 95% confidence interval (CI) were estimated by applying Cox proportional‐hazards model in each study. These hazard ratios were integrated using a random‐effects model. Among 187,999 women , we observed 873 premenopausal and 1,456 postmenopausal cases. Among premenopausal women, use of female hormones significantly increased BC incidence (HR: 1.53 [1.04–2.25]). Although P value for trend was not significant for age at first birth and number of births , women giving first birth at ages ≥36 experienced significantly higher BC incidence than at ages 21–25 years, and women who had ≥2 births experienced significantly lower BC incidence than nulliparous women. Among postmenopausal women, more births significantly decreased BC incidence (P for trend: 0.03). Although P value for trend was not significant for age at first birth and age at menopause , women giving first birth at ages 26–35 years experienced significantly higher BC incidence than at ages 21–25 years, and women with age at menopause: ≥50 years experienced significantly higher BC incidence than age at menopause: ≤44 years. BC incidence was similar according to age at menarche or breastfeeding history among both premenopausal and postmenopausal women. In conclusion, among Japanese women, use of female hormones increased BC incidence in premenopausal women, and more births decreased BC incidence in postmenopausal women. Person years were calculated from the baseline date till the date of breast cancer diagnosis, date of death, and lost to follow‐up or the end of the study follow‐up, whichever occurred earliest.We conducted analyses according to the menopausal status at baseline and according to the menopausal status at breast cancer diagnosis. Because none of the studies collected information on menopausal status after baseline, we hypothesized that women who were in premenopausal status at baseline became postmenopausal when they passed their 51st birthday. We set a cut point at age 51 based on prior studies.For all population‐based cohort studies, we calculated hazard ratio (HR) and 95% confidence interval (CI) by applying the Cox proportional‐hazards model. The reference category of each reproductive factor was defined as follows: ≤12 years (age at menarche), 21–25 years (age at first birth), nulliparous (number of births), ≤44 years (age at menopause), never , and never (breastfeeding history). We applied two different models: model 1 in which we adjusted age and area , model 2 in which we adjusted age, area , history of smoking , body mass index (BMI) , history of drinking , environmental tobacco smoke (ETS) exposure during childhood  (for studies excluding TAKAYAMA and LSS), environmental tobacco smoke (ETS) exposure at home and/or at work  (for studies excluding TAKAYAMA and LSS), and mutually adjusted by each reproductive factor. Model 2 was the primary analytic model for the present study. Analyses on age at first birth were conducted among parous women. Age at menopause was not adjusted in the analyses on premenopausal at baseline or premenopausal at diagnosis. We created indicator terms for missing data of categorical variables. We also estimated the increase of breast cancer incidence per category of each reproductive factor by calculating P value for trend.2‐statistic.In each population‐based cohort study, the cohort‐specific hazard ratio and 95% CI were calculated. Then, they were combined by applying the random‐effects model.p values were two‐sided, and we considered p value <0.05 as statistically significant.We conducted analyses by using SAS statistical software package version 9.3  or version 9.4 , SPSS Statistics version 25.0 (JACC), Stata/MP 14.2 (AICHI), Stata/SE 15.1 (LSS), and Stata/MP 16.0 (random‐effects model). 3The baseline information of nine studies included in our analyses was summarized Table . 187,999Table p for trend: <0.01), and breastfeeding history significantly decreased breast cancer incidence . Model 1 also showed that age at menarche, number of births, age at menopause, and use of female hormones were not associated with breast cancer incidence . Model 2 showed that more births significantly decreased breast cancer incidence (p for trend: 0.03). Model 2 also showed that age at menarche, use of female hormones, and breastfeeding history were not associated with breast cancer incidence . Although P value for trend was not significant on age at first birth and age at menopause , women giving first birth at ages 26–30 or 31–35 years experienced significantly higher breast cancer incidence than women giving first birth at ages 21–25 years , and women whose age at menopause: 50–54 or ≥55 years experienced significantly higher breast cancer incidence than age at menopause: ≤44 years .Among postmenopausal women at baseline, model 1 showed that higher age at first birth significantly increased breast cancer incidence (p < 0.001) in model 2.Supplementary Table 4The present study targeted more than 180,000 Japanese women, and elucidated the association of reproductive factors with the incidence of breast cancer. Among premenopausal women, use of female hormones significantly increased premenopausal breast cancer. Although P value for trend was not significant for age at first birth and number of births, women giving first birth at ages ≥36 experienced significantly higher incidence and women who had ≥2 births experienced significantly lower incidence. Among postmenopausal women, more births significantly decreased breast cancer incidence. Although P value for trend was not significant for age at first birth and age at menopause, women giving first birth at ages 26–35 years and women with age at menopause ≥50 years experienced significantly higher breast cancer incidence. Breast cancer incidence was similar regardless of age at menarche or breastfeeding history among both premenopausal and postmenopausal women.Lower age at menarche has been regarded as one of the risk factors of breast cancer.Significantly higher breast cancer incidence was observed in women with age at menopause: 50–54 and ≥55 years than those with age at menopause: ≤44 years. Although a previous meta‐analysis in Japan The association of parity with breast cancer incidence was also reported in previous studies.In the present study, use of female hormones significantly elevated the incidence of breast cancer among premenopausal women. However, we did not observe this association among postmenopausal women. Few studies in Asia analyzed the impact of female hormones on breast cancer, mainly due to lower prevalence of such hormone use compared with Western countries.We did not find an association between history of breastfeeding and breast cancer, and this result was inconsistent with some of the previous studies.This study has four limitations: (1) we could not conduct pooled analyses according to hormone receptor or histology because this information was missing in some of the included cohort studies; (2) we could not evaluate the association between breast cancer risk and duration of female hormones’ use, type of female hormones including hormone replacement therapy (HRT), oral contraceptive (OC), or breastfeeding because most of included studies did not collect this information; (3) we could not calculate hazard ratio per 1‐year increase in age at menarche/menopause/first birth because several studies which were included in this pooled analysis collected this information as categorical variables, not as continuous variables; (4) there might be other unmeasured confounding factors that affected our study results.In conclusion, in Japan, use of female hormones significantly increased premenopausal breast cancer, and greater number of births significantly decreased breast cancer risk in postmenopausal women. However, breast cancer risk was similar according to age at menarche/breastfeeding history in both premenopausal and postmenopausal women. Although some of reproductive factors studies in the present study are not modifiable factors, understanding high‐risk population would be important for preventing breast cancer including chemoprevention and early detection. Further studies would be needed to elucidate the impact of reproductive factors according to hormone receptors or histology.None declared.All the authors 1) have made substantial contributions to conception and design, or acquisition of data, or analysis and interpretation of data; 2) were involved in drafting the manuscript or revising it critically for important intellectual content; 3) gave final approval of the version to be published. Each author participated sufficiently in the work to take public responsibility for appropriate portions of the content; and 4) agreed to be accountable for all aspects of the work in ensuring that questions related to the accuracy or integrity of any part of the work are appropriately investigated and resolved.Supplementary MaterialClick here for additional data file.


Alcohol intake is associated with the risk of breast cancer. Different patterns of alcohol-drinking may have different effects on breast cancer even when keeping constant the total amount of alcohol consumed. We aimed to assess the association between binge drinking and breast cancer risk. The SUN Project is a Spanish dynamic prospective cohort of university graduates initiated in 1999. In the 556-item lifestyle baseline questionnaire a validated food-frequency questionnaire was embedded. Participants completed biennial follow-up questionnaires. Cox regression models were used to estimate the hazard ratio (HR) for breast cancer associated with the exposure to binge drinking. A stratified analysis was performed according to menopausal status. We included 9577 women , with a median follow-up of 11.8 years. Among 104,932 women-years of follow-up, we confirmed 88 incident cases of breast cancer. Women in the binge drinking group showed a higher risk of breast cancer  compared to women in the non-binge drinking category. In the stratified analysis, a 2-fold higher risk for premenopausal breast cancer was associated with binge drinking habit . This study adds new evidence on the association of binge drinking with breast cancer risk. In recent years, the prevalence of heavy drinking and binge drinking in developed countries has increased notably . ReporteIn 2010, the International Agency for Research on Cancer (IARC) classified alcohol as a Group 1 carcinogen . EpidemiPrevious observational prospective studies found a 30–50% relative increase in breast cancer risk associated with binge drinking ,11,12. HSome experimental studies have linked binge drinking with an increase in inflammation levels as well as insulin resistance . Both meWe aimed to assess the impact of episodic heavy drinking and the subsequent risk of breast cancer incidence in a middle-aged Mediterranean cohort of university graduates.The ‘Seguimiento Universidad de Navarra’ (University of Navarra Follow-up) (SUN) Project is a dynamic and multi-purpose cohort study entirely composed of university graduates. Recruitment started in 1999 and is currently ongoing. Participants are invited to complete a 556-item baseline questionnaire that includes questions about lifestyle, sociodemographic, anthropometric and medical variables. Those who completed the baseline questionnaire are contacted biennially thereafter and inquired about changes in their lifestyles and incident diseases. Details of the design and methods of this cohort study have been described elsewhere .n = 344) in the baseline questionnaire. We also excluded 1320 women with a daily energy intake below 500 or above 3500 kcal/d [Up to December 2018, 22,790 participants answered the baseline questionnaire. For the present analysis, 8791 men were excluded. We also excluded 229 participants who answered the baseline questionnaire after October 1st, 2015 to ensure a follow-up period of at least 2 years, and 1295 participants due to lack of follow-up . We further excluded 104 women who reported a previous breast cancer, and we also excluded participants with prevalent or previous diagnosis of cancer  was gathered. The baseline questionnaire also included further items on alcohol-drinking habits during the year preceding. Information including the maximum number of drinks consumed in a single weekday, or a day during the weekend, or in special occasions was collected in a categorical way . For our analysis, binge drinking was considered as the consumption of at least 6 alcoholic drinks in a single day. This definition is motivated by the categories of the questionnaire, and the implications of using this definition are discussed in depth in the discussion section.The diagnosis of breast cancer was initially self-reported. Patients who had reported a diagnosis of breast cancer were asked to provide a copy of their medical reports. These medical reports were subsequently used to confirm the cases by an independent expert who was blinded to the exposure. We also included as confirmed breast cancer cases, deaths due to breast cancer that had been identified through consultation of the National Death Index (NDI) in any case that the NDI adjudicated breast cancer as the cause of death. Alternatively, we included both confirmed and self-reported breast cancer cases pending confirmation as ‘probable breast cancer cases’.Information about sociodemographic, lifestyle and medical variables was obtained from the baseline questionnaire. The questionnaire included information on age of menopause, age of menarche, obstetric history, family history of breast cancer, and baseline chronic diseases.Physical activity was assessed through a validated questionnaire . AdherenAge at menopause was updated in the questionnaire after 16 years of follow-up. For those women with no available information on age at menopause, we used as cutoff point the 75th percentile of the age of menopause (52 years in our sample) .2), consumption of sugar-sweetened beverages (servings/day) and TV-watching (h/d). The consumption of sugar-sweetened beverages has been associated with breast cancer risk [Quantitative baseline characteristics of participants were summarized with means and standard deviations, and qualitative traits with proportions across different binge drinking habits. To assess the relationship between binge drinking and the risk of breast cancer, we fitted Cox regression models. We estimated Hazard ratios (HR) and their 95% confidence intervals (CI) for women in the binge group compared to women reporting no binge drinking habits (reference category). We used age as underlying time variable and stratified our analyses by recruitment period and age (decades). We first fitted models for overall breast cancer incidence and then separated analyses according to menopausal status. Participants were followed up until the date of breast cancer diagnosis for both confirmed and probable cases, date of death or last contact, whichever occurred first. We adjusted a multivariable model including as potential confounders height (cm), family history of breast cancer , smoking habit , lifetime tobacco exposure (pack-years), age of menarche , menopausal status, obstetric history , lifetime breast-feeding (months), hormone replacement therapy, years of university studies, physical activity (MET-h/week), alcohol consumption (g/day), adherence to the traditional Mediterranean Diet Score (0–8 points), total energy intake , body-mass index (BMI) , we used two-sided For the analysis, 9577 women were included, with a median follow-up of 11.8 years. Baseline characteristics of participants are described in During a total follow-up of 104,932 women-years, 167 probable incident cases of breast cancer were identified, out of which 88 were confirmed. Women in the binge drinking group showed a higher risk of breast cancer  compared to women in the non-binge drinking reference group, after adjusting for potential confounders . AccordiWhen we included probable breast cancer cases, results were attenuated . The HR In this prospective Mediterranean cohort, in relative terms, the risk of incident breast cancer was up to 76% higher in women with a binge drinking habit compared to women who drank without a binge drinking pattern.Alcohol consumption has been linked to a higher risk of breast cancer ,24,25,26Mediterranean Diet has been hypothesized to reduce the risk of breast cancer . AssessmWe identified three previous prospective cohorts that addressed the association between episodic heavy drinking and breast cancer risk. In the Danish Nurse Cohort study, women reporting binge drinking at weekends had a relative risk for breast cancer of 1.49 (95% CI 1.04–2.13) for 10–15 drinks and a relative risk of 2.51 (95% CI 1.37–4.59) for 16–21 drinks as compared to women reporting 1–3 drinks over the weekend . In the In the stratified analysis, we found a 2-fold higher risk of premenopausal breast cancer associated with binge drinking compared to women who did not binge in our cohort. The estimated risk was attenuated when considering all the probable breast cancer diagnoses. This could be partially explained by the fact that some of the probable breast cancer cases were in fact cases of benign breast disease . Few epidemiologic studies have assessed the association between alcohol consumption and risk for benign breast disease and results have been so far inconclusive ,30.We found no association between binge drinking and postmenopausal breast cancer. This may be partially explained by our very low number of postmenopausal breast cancer cases, and a lower proportion of binge drinkers among postmenopausal women. Given the relatively young mean age of the SUN Project , we found a higher proportion of premenopausal breast cancer cases than postmenopausal cases. The scarcity of postmenopausal breast cancer cases limits our ability to obtain firm conclusions of differential associations between binge drinking and an early onset of breast cancer. Another potential explanation for the lack of association is not focusing on the etiologically relevant exposure period. Some authors suggest that alcohol consumption during adolescence and early adulthood may have a greater adverse effect on risk of breast disease, especially before the age of first pregnancy .Multiple mechanisms have been described to explain the influence of alcohol in breast cancer risk. Alcohol per se can increase sex hormone levels and subsequently stimulate proliferation of estrogen-receptor positive cells . The avaHowever, some limitations must be taken into consideration. First, the SUN Project participants are relatively young, which may partially explain the low incidence of breast cancer, especially of postmenopausal breast cancer. As a consequence, this may limit the statistical power. Nevertheless, the identified age-adjusted incidence was consistent with the reported incidence of breast cancer in the Spanish population . Second,To our best knowledge, this is the first study to assess the relationship between binge drinking and breast cancer risk in a middle-aged Mediterranean population. The prospective nature of the SUN Project ensures the temporal sequence between exposure and outcome, including a large sample size with a long follow-up and a good retention rate. Moreover, the adjustment for a wide number of potential confounders and the sensitivity analyses assure the robustness of our findings. Self-reported cancer cases were confirmed via medical reports to ensure that the final diagnosis was an invasive breast carcinoma and not a benign tumor such as lipoma or fibroadenoma. Lastly, by excluding abstainers in our analysis we aimed to compare the direct effect of binge drinking versus drinking in a manner different from the binge pattern. Previous studies have frequently used the abstainer group as the reference category. However, artificially elevated rates of disease in abstainers can be due to a higher morbidity among former drinkers or to the avoidance of alcohol drinking because of medical causes. This interpretation corresponds to the ‘sick quitter’ hypothesis, that may introduce some degree of bias  and by eIn summary, in this Mediterranean cohort, a binge drinking habit was directly associated with a higher incidence of breast cancer. The risk of premenopausal breast cancer markedly increased for women in the binge drinking category. This study adds new evidence to the available knowledge concerning the adverse effects of heavy alcohol consumption on health.


Despite Saudi Arabia’s free and well-established cancer care program, breast cancer incidence and mortality are rising. Husbands’ knowledge, and wives’ attitudes and practices related to breast cancer screening are not well understood in Saudi Arabia.The aim of this study was to investigate husbands’ knowledge, and wives’ attitudes and practices related to breast cancer screening in Saudi Arabia.This cross-sectional study collected data from 403 husbands in the holy city of Makkah through an online self-reported questionnaire over a period of 2 months, from May 6 to July 7, 2020. Tabulation, bivariate, and multiple regression analyses were the major tools used for data analysis. Multivariate logistic regressions were used to examine the association between husbands’ knowledge and wives’ behavior regarding breast cancer screening methods.Husbands’ knowledge score (a 1-point increase) was significantly associated with the wives’ utilization of mammograms  and breast self-examination . Husbands’ knowledge also influenced the wives’ attitudes toward learning about breast self-examination . There was no significant association between husbands’ knowledge and wives’ utilization of clinical breast examination. However, richer husbands showed a socioeconomic gradient concerning their wives’ utilization of clinical breast examinations .Overall, husbands’ knowledge of breast cancer influences wives’ attitudes and practices related to breast cancer screening methods in Saudi Arabia. Thus, interventions delivered to husbands might increase breast cancer awareness and survival. Breast cancer is the leading cause of cancer-related deaths in women of over 100 countries, and is responsible for approximately 15% of all cancer deaths in women worldwide . MoreoveBreast cancer awareness contributes to the early detection of cancer presentation, and is thus necessary to reduce breast cancer incidence and mortality . EvidencSimilar to several countries in the Middle East and the Arab world, the KSA has a conservative culture, and men usually manage many of the decisions, choices, and actions of women ,19. A soThe aim of this study was to investigate the potential effect of husbands’ knowledge on their wives’ attitudes and practices related to breast cancer screening in the holy city of Makkah in the Makkah region of western Saudi Arabia, located 70 kilometers inland from Jeddah. Approximately 26% of the KSA population live in the Makkah region . Makkah This cross-sectional study was carried out in Makkah city of the Makkah region in the KSA from May 6 to July 7, 2020. Given the social/physical distancing measures implemented in the country because of the COVID-19 pandemic, data were collected via an online self-reported questionnaire using a Google Drive website. The link was distributed to potential participants via social media, including Twitter and WhatsApp groups.This study included participants who were residents of Makkah city and were male partners  aged between 20 and 80 years. According to the latest KSA census, Makkah has a total of 434,248 married men  . The minThe questionnaire was developed by the authors based on several previous studies ,14,19,20On the first page of the online questionnaire, participants were provided with the study background, aim, and objectives. They were informed that they did not have to complete the questionnaire and were free to withdraw at any point without providing a reason. They were also informed that there would be no sensitive personal questions, and all information provided would be anonymous, confidential, and used for research purposes only. Participants aged 20 years or over living in Makkah city, who understood the content of the questionnaire, and agreed to participate in the study were instructed to start the questionnaire. Online informed consent was obtained from all participants before proceeding with the questionnaire.In this study, we defined four outcome variables: variables related to wives’ practices of breast self-examination (BSE) , clinical breast examination (CBE) , and mammograms , and a variable related to wives’ attitudes toward learning about BSE . The main exposure variable of this study was the husbands’ knowledge scores. Using predetermined answer keys based on medical evidence, each correctly answered knowledge question was awarded one knowledge point. Incorrectly answered questions or “I don’t know” responses were awarded zero knowledge points.There were 20 knowledge questions in the questionnaire, including two questions on BSE (age of commencement and frequency), one question on CBE (age of commencement), two questions on mammograms (age of commencement and frequency), five questions on symptoms , six questions on risk factors , and four questions on protective factors . The total knowledge score was computed by adding up the points for each of the 20 breast cancer knowledge questions, yielding a total breast cancer knowledge score between 0 and 20.Multivariate logistic regression analyses were performed controlling for the husbands’ sociodemographic covariates. We used age, nationality, education, occupation, and household monthly income level as the sociodemographic control variables. Age was categorized as 20-29 (reference category), 30-39, 40-49, 50-59, and ≥60 years. Nationality was categorized as non-Saudi (reference category) and Saudi. Education was categorized as high school education level or less (reference category) and college/university degree or higher. Occupation was split into the categories of unemployed or retired (reference category), self-employed, government employee, and private sector employee. Household monthly income was grouped into two categories: less than 10,000 Saudi Riyal (SR) (reference category) and ≥10,000 SR (1 SR=US $0.27).2 goodness-of-fit test was used to assess the statistical significance of the husbands’ indicators of knowledge on breast cancer signs and preventive measures. Multivariate logistic binary regression analysis was used to assess the correlations between the husbands’ knowledge about breast cancer and their sociodemographic, educational, and economic factors with their wives’ various types of breast screening behaviors. The associations are expressed as adjusted odds ratios with 95% CIs. The SPSS version 20 software package was used to perform all statistical analyses.Tabulation, bivariate, and multiple regression analyses were the major data analytic tools used in this study. Means (SD) are used to describe the continuous variables, whereas frequency and percentages are used to describe the categorical variables. The nonparametric univariate χAll procedures performed in this study involving human participants were performed in accordance with the ethical standards of the institutional or national research committee and with the 1964 Helsinki Declaration and its later amendments or comparable ethical standards. This study was reviewed and approved by the King Abdulaziz University Research Ethics Committee, and was designed and performed in accordance with the ethical principles established by the university. This study also received ethical approval from the Ministry of Health of the KSA (IRB no: H-02-K-076-0320-275). Online informed consent to participate was secured from all respondents who participated in this study. The data collection procedure was anonymous and as such no personal identifying information was collected. The data were stored on the first author’s password-protected personal computer. An additional copy of the data was stored on a password-protected external drive kept by the first author to serve as a backup.A total of 445 participants completed the questionnaire. After excluding 42 respondents who reported living outside of Makkah city, the final sample consisted of 403 participants. The majority of participants were Saudi citizens, and the others comprised expatriate men residing in Makkah city. Of the 403 participants, over half were aged 40 or older, over three-quarters had a college/university or a postgraduate degree, and just over half worked in various governmental jobs. Over one-third of participants had a household monthly income of less than 10,000 SR.In general, the basic knowledge and awareness of female BSE, CBE, and mammograms was low among the husbands in Makkah city. The majority of the husbands had heard about female BSE; however, when asked about the stage at which women should start BSE, just over a quarter of the respondents correctly inferred that they should start from the age of 20. The same proportion also correctly suggested that monthly BSE is recommended for women. In contrast, over half of the respondents had not heard about CBE, and only about 35% of the husbands correctly answered that the recommended time of CBE is from the age of 40 or when women have symptoms. Furthermore, approximately 60% of the husbands had heard about mammograms. However, less than half of the respondents correctly inferred that the recommended starting age of mammograms is from the age of 40 or higher. Similarly, only about a third of the husbands correctly suggested that the recommended frequency of mammograms for women is every 1-2 years.The husbands’ poor knowledge of breast cancer screening was also reflected in their wives’ attitudes and practices related to these behaviors. As shown in The results related to the husbands’ knowledge of female breast cancer symptoms, risk factors, and preventive measures are shown in The most frequent symptom of breast cancer that had been correctly identified was the sign of lymphadenopathy, followed by changes in nipple morphology, nipple discharge, changes in breast size, and nipple skin dryness. Similarly, the most frequent risk factor of breast cancer mentioned by husbands was hereditary factors, followed by cigarette smoking, overexposure to radiation, older age, use of contraceptives, and hormonal replacement therapy. In addition, the most frequent protective factor of breast cancer known to husbands was natural breastfeeding, followed by a balanced and healthy diet, regular exercise, and early conception before the age of 30.The knowledge score of the husbands was calculated from the scores of the 20 knowledge questions shown in The results also revealed that husbands who were employed in the private sector had more than a 4-times higher odds that their wives had performed mammography screening than those who were retired or unemployed. Similarly, the husbands with higher household monthly income levels  had approximately 2-times higher odds that their wife had undergone a mammogram and had more than 2-times higher odds that their wives had undergone a CBE. Additionally, the husbands’ high knowledge score was significantly associated with their wives’ utilization of mammograms and BSE, as well as their wives’ willingness to learn more about BSE. However, no association between husbands’ knowledge scores and wives’ utilization of CBE screening was found .Although previous studies have addressed the knowledge and attitude of breast cancer screening among Saudi women, this study illustrates the impact of husbands’ knowledge on their wives’ breast cancer screening behavior in Makkah city of the KSA using an online cross-sectional survey. The findings revealed that husbands’ knowledge has an important impact on their wives’ attitudes and practices related to the utilization of breast cancer screening methods. This study also showed socioeconomic gradients concerning wives’ utilization of mammogram and CBE.Breast cancer survival is closely associated with cancer awareness ,24. BecaOne of the major findings of this study was that the husbands’ knowledge was significantly associated with their wives’ utilization of mammograms and BSE. This study also found that a 1-point increase in the husbands’ knowledge scores on breast cancer increased the odds of mammogram utilization by approximately 1.1 times and increased the odds of BSE utilization by approximately 1.2 times. In addition, a 1-point increase in the husbands’ knowledge scores on breast cancer increased the odds of their wives’ being willing to learn about BSE by approximately 1.1 times. If considered cumulatively, our findings suggest that the husbands’ knowledge substantially increased the probability of their wives’ participation in mammogram and BSE screening methods. Similar findings were also reported in another study .Most previous studies have not controlled for all socioeconomic factors when investigating husbands’ knowledge about breast cancer -22. HoweIn line with existing evidence , our stuIn the KSA, a large number of breast cancer cases are discovered at late stages, which leads to a lower rate of recovery . DespiteThe findings of this study should be interpreted in light of some limitations. This research concerned the Makkah region and urban settings only, where the majority of the men were well educated. In addition, the study design was cross-sectional in nature with the possibility of recall and self-reporting biases. Finally, the descriptive analysis cannot be generalized to all husbands in the KSA, as study participants were recruited through a convenience sampling method. However, care was taken to recruit participants that preserve the sociodemographic distribution of the KSA and, as already discussed, our descriptive analysis did not contradict the findings of past studies.This study found evidence that husbands’ knowledge about breast cancer has an important role in encouraging the breast cancer screening behaviors of their wives. Furthermore, the study findings documented limited knowledge about breast cancer among Makkah residents. Moreover, the wives of elderly husbands, according to their husbands’ beliefs, are less willing to learn about BSE, whereas younger husbands’ wives had higher odds of performing BSE. We also found some limited socioeconomic gradients regarding the utilization of mammograms and CBEs. These findings have important implications for conservative cultures where men play a crucial role in women’s decisions and actions. Policies could be directed to raise breast cancer awareness, and interventions could be devised such that high-risk groups  adhere to the recommended cancer screening protocol. Efforts should be made to empower women so that barriers to seeking medical help are alleviated. Future research is needed to evaluate whether implementing breast cancer awareness interventions increases cancer survival.


At present, the relationship between hypothyroidism and the risk of breast cancer is still inconclusive. This meta-analysis was used to systematically assess the relationship between hypothyroidism and breast cancer risk, and to assess whether thyroid hormone replacement therapy can increase breast cancer risk.The relevant articles about hypothyroidism and the risk of breast cancer were obtained on the electronic database platform. Relevant data were extracted, and odd ratios (OR) with corresponding 95% confidence intervals (CI) were merged using Stata SE 12.0 software.A total of 19 related studies were included in the meta-analysis, including 6 cohort studies and 13 case-control studies. The results show that hypothyroidism was not related to the risk of breast cancer . In the European subgroup, we observed that patients with hypothyroidism have a lower risk of breast cancer. Furthermore, no significant correlation was observed between thyroid hormone replacement therapy and the risk of breast cancer. .Hypothyroidism may reduce the risk of breast cancer in the European population, and no significant correlation was observed between hypothyroidism and breast cancer risk in non-European populations. Due to the limited number of studies included, more large-scale, high-quality, long-term prospective cohort studies are needed. As a global public health problem, breast cancer has an increasing incidence on a global scale . AccordiThe physiology and pathology of the breast are closely related to the endocrine of the body . As the Two meta-analyses have previously been studied for hypothyroidism and breast cancer risk , 12. BasRelevant clinical literature was extracted by systematic retrieval of PubMed (Medline), EMBASE, Springer, Web of Science, and Cochrane Library electronic databases up to date to October 2019. Our search strategy included terms for: “thyroid dysfunction” or “hypothyroidism” or “HT” and “thyroid diseases” or “breast cancer” or “BC” or “breast neoplasms” or “mammarmy cancer” and “risk” or“incidence”. At the same time, we manually screened out the relevant potential literature in the references extracted.The inclusion criteria:Types of studies: Published studies exploring the relationship between hypothyroidism and breast cancer risk;Subject: Female;Exposure factors: Primary hypothyroidism, the diagnosis needs to be based on the detection of thyroid function;Outcome indicators: the occurrence of primary breast cancer.Non-primary hypothyroidism due to other causes;Non observational studies;Insufficient information was provided or no full-text;Unable to obtain full text or quality assessment of the literature;Studies were repeated or publications overlapped.The exclusion criteria:Two researchers separately conducted literature screening, data extraction, and literature quality evaluation, and any differences could be resolved through discussion or a third inspector. Information secured from the enrolled literature included: first author’s surname, year of publication, country of the population, sample size, follow-up time, and data on the relationship between hypothyroidism and the risk of breast cancer.The Newcastle-Ottawa Scale (NOS) was used to assess the quality of the study from three aspects: cohort selection, cohort comparability, and outcome evaluation . NOS scoP ≥ 0.05 or I2 < 50% was performed, it mean that there was no apparent heterogeneity, and the fixed-effect model should be applied for a merger. When P < 0.05 or I2 ≥ 50% indicated high heterogeneity, the random-effect model was applied. Combined effect size, if OR > 1 indicates that hypothyroidism is an unfavorable factor for breast cancer. If OR < 1 is the opposite. Publication bias Begg funnel plot and Egger test linear regression test were used to research publication bias detection of the literature included. If P  < 0.05 indicates obvious publication bias.All data analysis was performed using Stata12.0 software. Meta-analysis was performed according to the PRISMA guidelines. The OR and 95%CI from included studies were treated with the combined effect size. After that, the heterogeneity test was conducted. When A total of 2415 studies were identified on our online databases. After exclusion of duplicate references,129 articles were considered. After screening the abstract and title, 102 articles were excluded. After careful review of the full texts, 8 studies have been excluded because 5 of them did not provide relevant data, and 3 articles did not have full-text. Nineteen articles published between 1978 and 2019 met the inclusion criteria  among these studies, so a random effect model was used for assessment. The pooled analysis suggested that was not related to the risk of breast cancer . In the subgroup with a follow-up date of more than four years, patients with hypothyroidism can reduce the risk of breast cancer, with borderline significance . In other subgroups, we found that hypothyroidism was not related to the risk of breast cancer.To further explore the relationship between hypothyroidism and breast cancer risk, subgroup analysis was conducted from three aspects: study type, population distribution, and follow-up time. The results of subgroup analysis were shown in Table 2 = 86.3%, p = 0.000). The result suggested that patients who received thyroid hormone replacement therapy was not related to the risk of breast cancer   and the Egger test(P = 0.892) were used to detecting publication bias showed that there was no possibility of publication bias. As shown in Fig. P = 0.672, and the Begg test was Pr = 0.858.Figure P < 0.001), and there was no heterogeneity.The results of sensitivity analysis are generally stable, and the primary source of heterogeneity is in the research of Cristofanilli et al. .Fig. 5)5). So weMore than 100 years ago, Beatson et al. used thyroid extracts to treat patients with metastatic advanced breast cancer. The condition was significantly alleviated, sparking interest in exploring the relationship between thyroid and breast cancer . SubsequA total of 19 studies were included in this meta-analysis, and the results showed that patients with hypothyroidism not related to the risk of breast cancer. However, there was significant heterogeneity among the included studies. After subgroup analysis and sensitivity analysis, we found that Cristofanilli’s research may cause heterogeneity . CristofIn the analysis of the European population, the results show that hypothyroidism may reduce the risk of breast cancer. We also found that patients with hypothyroidism can reduce the risk of breast cancer was borderline significance in the subgroup with more longer follow-up date. However, the relationship between the two was not observed in North American and Asian populations. The possible reasons for these disparities may be as follows. First, follow-up time may be the main contributors to this difference. A longer follow-up is required to demonstrate the relationship between hypothyroidism and breast cancer risk. In the meta-analysis, five studies provided North American population data, and two reported Asian population data. However, only one of seven non-European studies’ follow-up time for more than 4 years. Second, the differences may be attributed to different ethnicities sharing different gene-gene and gene-environmental backgrounds. Third, social and environmental factors are another critical cause for this difference. With these in mind, our findings suggest that hypothyroidism may reduce the risk of breast cancer only in the European population and more large-scale, high-quality, long-term prospective cohort studies are still needed to study on different human populations.The following may explain the potential relationship between hypothyroidism and the risk of breast cancer. Healthy mammary epithelial cells can express a large number of T3 receptors, and breast cancer cells have a similar ability to bind to T3 . T3 has Some basic experiments support this theory. In 2002, Gonzalez-Sancho et al. studied the relationship between T3 and breast cancer . It was However, this conclusion needs to be taken with caution, as this study has several limitations. First, the studies that have been included do not adjust for important risk factors for breast cancer. Second, in subgroup analysis, for example, there are only two articles in Asian studies, and we should be cautious about the results of Asian analysis. Third, the results of this meta-analysis indicate that there is a large heterogeneity between studies. Fourth, follow-up time at different endpoints cannot be uniform. Finally, publication bias cannot be avoided entirely.Hypothyroidism may reduce the risk of breast cancer in the European population, and no significant correlation was observed between hypothyroidism and breast cancer risk in non-European populations. Furthermore, there was no obvious correlation between thyroid hormone replacement therapy and breast cancer risk. It is necessary to conduct a large sample size, strictly controlled prospective study of hypothyroidism patients further to demonstrate the relationship between hypothyroidism and breast cancer risk.


One SNP (rs6431625) in the promoter region of the uridine-diphosphoglucuronate glucuronosyltransferase1A1 (UGT1A1) gene explained 16.9% and the remaining 114 SNPs (non-UGT1A1 SNPs) explained 3.1% of phenotypic variance in circulating bilirubin levels. A one-standarddeviation increment in circulating bilirubin (≈ 4.4 µmol/L), predicted by non-UGT1A1 SNPs, was inversely associated with risk of squamous cell lung cancer and Hodgkin’s lymphoma (odds ratio (OR) 0.85, 95% confidence interval (CI) 0. 73–0.99, p 0.04 and OR 0.64, 95% CI 0.42–0.99, p 0.04, respectively), which was confirmed after removing potential pleiotropic SNPs. In contrast, a positive association was observed with the risk of breast cancer after removing potential pleiotropic SNPs . There was little evidence for robust associations with the other seven cancers investigated. Genetically raised bilirubin levels were inversely associated with risk of squamous cell lung cancer as well as Hodgkin’s lymphoma and positively associated with risk of breast cancer. Further studies are required to investigate the utility of bilirubin as a low-cost clinical marker to improve risk prediction for certain cancers.Bilirubin, an endogenous antioxidant, may play a protective role in cancer development. We applied two-sample Mendelian randomization to investigate whether genetically raised bilirubin levels are causally associated with the risk of ten cancers . The number of cases and their matched controls of European descent ranged from 122,977 and 105,974 for breast cancer to 1200 and 6417 for Hodgkin’s lymphoma, respectively. A total of 115 single-nucleotide polymorphisms (SNPs) associated ( Cancer is a major cause of morbidity and mortality globally, and the number of new cancer cases is expected to increase further over the next decades . In 2018, there were over 18 million new cancer cases and nine million cancer-related deaths /genetic effect on total bilirubin levels [βbilirubin]). Estimated risk effects were obtained for each genetic variant, named Wald estimate  as an evidence of directional horizontal pleiotropy, identifies outlier SNPs, and tests if the presence of outliers is biasing the estimation of risk (pDistortion).The initial step in the sensitivity analyses was to apply the inverse-variance weighted (IVW) MR approach  and to aTo evaluate the extent to which directional pleiotropy may affect the risk estimates, we used the intercept test within a MR-Egger weighted linear regression approach . MoreoveAnalyses were performed stratified by sex for pancreatic and renal cell cancers, also by subtypes for lung, ovarian, and breast cancer. We did not account for multiple testing, since we had a strong prior hypothesis based on biological plausibility and applying a strict multiple testing correction would likely have been overly conservative given the non-independence of risk for many of the cancers tested .MR-PRESSO, Two-Sample MR, gwasrapidd, and ggplot2; The R project). All statistical tests were two-tailed. Scatter plots were used to depict the genetic association on total bilirubin levels and cancer risk. All statistical analyses and plots were performed using Stata SE14  and R  that our analyses were able to detect for the UGT1A1 gene was not associated with risk of pancreatic cancer  0.95–1.11), whereas higher bilirubin levels predicted by non-UGT1A1 SNPs showed an inverse association with pancreatic cancer overall , with similar risk estimates among men and women  (Each standard deviation (SD ≈ 4.4 µmol/L) increment in bilirubin levels predicted by rs6431625 in the ctively) A. Howevectively) . The scaUGT1A1 SNP nor the non-UGT1A1 SNPs were associated with risk of renal cell cancer in men and women combined . After removing potential pleiotropic SNPs (n = 22), these associations were attenuated toward the null   B. In strectively B. The scectively .UGT1A1 SNP were weakly inversely associated with risk of ovarian cancer overall and serous ovarian cancer with ORs per 1-SD increment equal to 0.96 (95% CI 0.92–1.00) and 0.94 (95% CI 0.90–0.98), respectively. In contrast, we observed a positive association between bilirubin levels predicted by non-UGT1A1 SNPs and risk of ovarian cancer overall and serous ovarian cancer with ORs per 1-SD increment equal to 1.10 (95% CI 1.00–1.21) and 1.12 (95% CI 1.00–1.24), respectively   , while n42–0.99) .pDistortion > 0.25) (pintercept = 4 × 10−4) and returned a potential positive association between bilirubin levels, predicted by non-UGT1A1 SNPs, and endometrial cancer   . Additio99–1.89) . The wei99–1.89) . Finally99–1.89) .In this hypothesis-driven two-sample MR study, we investigated potential causal associations between genetically raised circulating bilirubin levels, a purported endogenous antioxidant, and risk of cancers of the pancreas, renal cell, endometrium, ovary, breast, prostate, lung, Hodgkin’s lymphoma, melanoma, and neuroblastoma. We found that genetically raised bilirubin concentrations were inversely associated with risk of squamous cell lung cancer and Hodgkin’s lymphoma, which is compatible with the antioxidant hypothesis of bilirubin, but positively associated with risk of breast cancer. N cases = 240) [N cases = 386) [The observed inverse association between genetically raised bilirubin levels and lung cancer risk among ever smokers, but not among never smokers, in our study are congruent with a prospective study in the UKB . Similars = 240)  and in as = 386) . Furthers = 386) ,49.We observed robust inverse associations between genetically raised bilirubin levels and risk of Hodgkin’s lymphoma.Our study is the first linking bilirubin metabolism to Hodgkin’s lymphoma. Given that one of the hypothesized root causes of Hodgkin’s lymphoma is infection by Epstein–Barr virus , bilirubUGT1A1 SNPs, and risk of breast cancer, in particular of the ER positive subtype . These associations were relatively robust to a range of sensitivity analyses  suggested that the UGT1A1*28 allele 7/7 genotype is a potential risk factor for breast cancer in Caucasians [There was a suggestive positive association between bilirubin levels, genetically predicted by non-analyses . A meta-ucasians . Given tucasians  suggestsUGT1A1 SNP were inversely associated with risk of ovarian cancer overall and serous ovarian cancer. If the inverse associations were genuine, then these findings are potentially consistent with a second-line antioxidant defense of raised bilirubin levels in the epithelial lining of the ovaries. Similar to lung cancer, oxidative stress is a critical factor in the initiation and development of ovarian cancer [UGT1A1 polymorphism in relation to ovarian cancer risk, and further studies are warranted.In contrast to breast cancer, bilirubin levels predicted by the n cancer . We are UGT1A1 SNP were inversely associated with risk of CRC, supporting our hypothesis of anti-oxidative and anti-inflammatory properties of bilirubin. However, among men, bilirubin levels predicted by the UGT1A1 SNP were positively associated with risk of CRC, and we argued that this could indicate either pleiotropic effects but potentially also pro-oxidative effects of an elevated bilirubin distribution among individuals with GS. The findings for pancreatic cancer resemble the results of our previous two-sample MR study on the role of genetically raised bilirubin levels in colorectal cancer (CRC) using the same set of SNPs as instrumental variables . We showWe found no strong evidence for an association between genetically raised bilirubin levels and the risk of renal cell cancer, prostate cancer, melanoma, and neuroblastoma. UGT1A1 instruments to detect small effects in some cancers. For these cancers, associations can occur by chance, especially when using weak instruments and small samples, which is a phenomenon known as weak instruments bias [UGT1A1 SNP affects cancer risk through pathways other than elevated bilirubin levels. There is a large region of linkage disequilibrium across the UGT1A locus that includes functional polymorphisms in UGT [UGT1A1 SNP across cancer types may also reflect the modulated metabolism of such substances with carcinogenic potential. We also acknowledge that GWAS of associations of genetic variants on chronic diseases can be prone to selection bias from surviving competing risk. Methods to assess genetic effects on chronic diseases are needed to account for competing risk before recruitment [Our study has several strengths. First, we used thousands of cases and controls from several large genetic consortia and published GWAS, which signified the largest and most comprehensive MR study on genetically raised bilirubin levels and cancer risk. Second, our MR assumptions were met, which were supported by our sensitivity methods and pleiotropic SNPs exclusion. Finally, common sources of bias in observational studies, including residual confounding and reverse causation, were likely reduced. This study has some limitations, first, a potentially under-powered sample size for the non-nts bias . Second,s in UGT ,59, whics in UGT  or sex hs in UGT . Thereforuitment .Finally, we were not able to analyze non-linear associations, which would necessitate individual-level data. However, a non-linear relationship between bilirubin levels and cancer was not previously observed . Genetically raised bilirubin levels were inversely associated with risk of squamous cell lung cancer as well as Hodgkin’s lymphoma, and positively association with risk of breast cancer. These findings should help in setting priorities in future research on bilirubin levels and cancer risk. If confirmed in other studies, bilirubin could be a promising marker to risk stratify individuals for more frequent screening of selected cancers.


To date, limited data are available on metabolic syndrome prevalence among breast cancer survivors in Malaysia. Therefore, this study was conducted to determine the prevalence of metabolic syndrome and abnormal metabolic syndrome components among breast cancer survivors in East Coast of Peninsular Malaysia.This cross-sectional study included 95 breast cancer survivors (age 53.7 ± 7.6 years) who have completed main cancer treatments for ≥6 months. Cancer survivors were recruited from two main government hospitals in Kelantan and Terengganu using a purposive sampling method.p < 0.05) between those with and without metabolic syndrome. Significant differences between metabolic syndrome and non-metabolic syndrome groups were found for weight, BMI, waist circumference, body fat percentage and cancer stages (p < 0.05). However, no significant relationship was reported between sociodemographic, clinical parameters and metabolic syndrome among breast cancer survivors in this study.According to the Harmonized criteria, the metabolic syndrome prevalence was 50.5%. Among those with metabolic syndrome, the most prevalent abnormal metabolic components were triglycerides (91.2%), fasting blood glucose (79.6%) and HDL-c level (78.4%). Except for total cholesterol and LDL-c, all other metabolic syndrome components were significantly different (Metabolic syndrome was highly prevalent among breast cancer survivors. It is recommended for health care professionals to closely monitor and improve the triglycerides, blood glucose and HDL-c level of the breast cancer survivors under their care to control the detrimental effect of metabolic syndrome.The online version contains supplementary material available at 10.1186/s12889-021-10288-9. The growing number of data have shown that metabolic syndrome (MetS) and its independent components are related with plethora of cancers, including a higher risk of having breast cancer –3. SimilIn contrast, there are a lot more studies conducted on MetS prevalence among the general population. In Malaysia, the prevalence of MetS has been extensively reported . To summDue to the inter-relationship between MetS and breast cancer, the study on MetS among breast cancer survivors could be a two-pronged investigation to counter these health issues at the same time. Nevertheless, up until today, limited data on the prevalence of MetS among breast cancer survivors in Malaysia have been published, especially in the East Coast of Peninsular Malaysia. Therefore, this study was conducted to determine the prevalence of MetS and abnormal MetS components among breast cancer survivors in East Coast of Peninsular Malaysia. In view of findings from a systematic review which indicates that breast cancer survivors are more susceptible to MetS , it is hg of 0.144, constant proportion of 0.182 based on a similar study from China [In this cross-sectional study, a total of 95 breast cancer survivors were recruited by using purposive sampling method from the surgical outpatient clinics of two main government hospitals in East Coast of Peninsular Malaysia with highest number of breast cancer cases; Hospital Sultanah Nur Zahirah in Terengganu and Hospital Raja Perempuan Zainab II in Kelantan. The surgical outpatient clinic attends all types of surgical patients and all breast cancer survivors were purposively sampled based on clinic contact list for breast cancer patients. Sample size were calculated using G*Power software version 3.1 with an effect size After obtaining ethical approval from the Ministry of Health and the administration of both hospitals, the name list of breast cancer survivors was obtained together with their contact numbers from the clinic. All breast cancer survivors were personally contacted to briefly explain the research and queried for inclusion and exclusion criteria. At the same time, all eligible breast cancer survivors were invited to join the study. Those who gave verbal consent were set up for an appointment. During the meetup session, study information sheets and further elaboration on the study procedure were given to all participants before written consent was obtained from each of them. All data were collected between November 2015 to February 2016.In this study, prevalence of MetS was first investigated by using the World Health Organization (WHO) , Nationa2) of the subjects according to the WHO classification [Weight and body fat percentage were measured to the nearest one decimal place using TANITA breast cancer-543 body composition monitor  while the subjects were standing still with weight equally distributed on both feet. To obtain the blood pressure data, OMRON HEM-7203 electronic blood pressure monitor  was used. All subjects were in a seated position and the measurements were taken after a 5-min rest. All anthropometric and blood pressure measurements were repeated two times and the average measurements were recorded. The body weight and height data were used to calculate and categorized the body mass index (BMI)  and fasting blood glucose. Meanwhile, low-density lipoprotein cholesterol (LDL-c) level was calculated using the Friedewald formula. The fasting blood glucose and lipid profiles analyses were conducted by using a fully-automated chemistry analyzer Olympus AU 400  with standard enzymatic and colorimetric methods. Information on sociodemographic profiles of the breast cancer survivors was acquired by using a self-administered questionnaire, whereas additional clinical and treatment data were obtained from the patients’ medical records using data collection form. Both the questionnaire and data collection form were pre-tested prior to actual data collection. The pre-test of questionnaire with patients suggested some amendments to the phrases used to increase clarity and reduce recall bias. Meanwhile data collected from patients’ medical reports by two researchers (AN and NSZ) using the data collection form was found to be consistent with 100% agreement when cross checked by the clinician.p-value of less than 0.05. The relationship between characteristics of study sample and metabolic syndrome was also tested using multiple logistics regression with metabolic syndrome status as a dependent variable (outcome) and sociodemographic and clinical variables as covariates. All statistical analysis was conducted by using IBM SPSS for Windows software, version 22.0 . There were no missing data in this study for all variables.Descriptive statistics were used to summarize demographic, anthropometric, biochemical and clinical data of the study sample. Parameters with normal data distribution were reported as mean with standard deviation, while others were reported as the median and interquartile range (IQR). To compare the differences in clinical, metabolic, sociodemographic and anthropometric characteristics according to MetS status, statistical analyses to compare two independent groups were used namely Chi-square test for categorical data and independent t-test for continuous data. Statistical significance was taken as a n = 95). Overall, the mean age ± SD of the subjects was 53.7 ± 7.6 years. Most of the cancer survivors were Malay (92.6%), married (72.9%), housewives (34.7%), had a maximum education level of secondary schools (64.2%) and a monthly income of less than MYR 1000 (USD 242) (36.8%). Next, majority of the cancer survivors were postmenopausal (87.4%), had prior experience of breastfeeding (88.4%), did not undergo hormone replacement therapy (83.2%) and had no family history of breast cancer (72.6%). Additionally, more than half of the breast cancer survivors did not take any oral contraceptive pill (54.7%). As there was no smokers or alcohol-drinkers among the breast cancer survivors, the link of these lifestyle factors with the presence of MetS could not be investigated.A total of 545 breast cancer survivors were listed at the hospital, but majority of them were unable to be reached by phone (44.4%), did not meet study criteria 11.4%), died (8.1%), or refused to participate (6.7%). Of the balance 160 eligible survivors, only 95 were included in the final analysis as 32 could not make it to the hospital during study period and 33 provided incomplete data. Table 1.4%, dieThe majority of the breast cancer survivors had stage II breast cancer (57.9%) and prolonged cancer survival duration, with the mean ± SD of 6.65 ± 4.19 years. Besides chemotherapy, most of them also had undergone surgery (98.9%) and radiotherapy (90.5%). As there was only a portion of breast cancer survivors reported to also be diagnosed with diabetes (17.9%), the median of fasting blood glucose level of all breast cancer survivors was reported to be slightly exceeding the normal value of 5.5 mmol per litre. Following the WHO classification for BMI, majority of the breast cancer survivors were overweight (45.3%), followed by obese (30.5%), normal (21.1%), and underweight (3.2%). Moreover, the high mean of waist circumference (88.8 cm) and the median body fat percentage (39.0%) indicated that the majority of breast cancer survivors tend to have central obesity.The overall prevalence of MetS among breast cancer survivors according to the Harmonized 2009, IDF 2005, ATP III 2001 and WHO 1998 criteria were reported to be 50.5, 48.4, 40.0 and 18.9% respectively (Table p < 0.001), fasting blood glucose (p < 0.001), systolic blood pressure (p = 0.006) and diastolic blood pressure (p = 0.020), as well as a significantly lower level of HDL-c (p < 0.001). In contrast, the total cholesterol and LDL-c levels were not significantly different among those with and without MetS. Significant difference between cancer stages and MetS was also found . In addition, breast cancer survivors with MetS had significantly higher body weight (p = 0.032), waist circumference (p = 0.003), BMI (p = 0.023) and body fat percentage (p = 0.020). This study also examined the relationship between characteristics of breast cancer survivors in this study and their metabolic syndrome status as shown in Table p > 0.05).Analysis of the characteristics of all research participants showed no significant difference in all reported sociodemographic and clinical profiles between those with and without MetS Table . MeanwhiMetS has been recognized as an important secondary target for the prevention of cardiovascular diseases and diabetes , as wellIn this study, the prevalence of MetS among breast cancer survivors in East Coast of Peninsular Malaysia showed a higher percentage of subjects with MetS, up to half of the proportion of the investigated breast cancer survivors. When compared with the recent report by The Malaysian Breast Cancer Survivorship Cohort (MyBCC) study on the prevalence of MetS among newly-diagnosed breast cancer patients, higher proportion of breast cancer survivors with MetS was reported in the current study 48.4%) compared to 37.8% in MyBCC study according to IDF 2005 definition . This di.4% compaThe higher proportion of breast cancer survivors with MetS in Asian countries as compared to Western countries reflected that MetS has become more prevalent in developing countries when compared to its Western counterparts due to increasing economic development in lower to middle-income countries , 34. ThiContrarily, MetS prevalence among general women population had also been reported in numerous studies. In Malaysia, MetS prevalence among general Malaysian women in three nationwide studies were reported to range between 30.1–43.7% –17. BesiIn the present study, among those with MetS as according to the Harmonized MetS definition (≥ 3 criteria), more than half of them met three MetS components, whereas 31.3 and 16.6% met four and five components respectively. However, when compared among all breast cancer survivors included in this study, the percentage of women meeting two MetS components (25.3%) was almost similar to those meeting three MetS components (26.3%). Furthermore, studies conducted among adults in China , ThailanMoreover, the most prevalent abnormal MetS parameters among all breast cancer survivors were abdominal obesity, followed by hyperglycemia and hypertension. Previous studies have also reported an almost similar trend of the top three most prevalent abnormal MetS parameters , 52–54. Meanwhile, previous literatures have described the links between MetS and other sociodemographic and lifestyle factors among Malaysian adults, such as higher age, unemployment, working in shifts, postmenopausal status, living in urban area, lower socioeconomic status, Indian ethnicity, Chinese ethnicity and lower education level , 41, 58.Similar to the findings of previous research, this study reported significant links between MetS and increased body weight , 60, 61,The differences in our findings may be attributed to several limitations of the study which should be addressed properly. Firstly, the breast cancer survivors included in this study were recruited only from Terengganu and Kelantan, hence the findings of this study might not represent all breast cancer survivors in Malaysia. Additionally, due to the sociodemographic characteristic and racial distribution of breast cancer survivors in Terengganu and Kelantan, data on breast cancer survivors from other ethnicities were very scarce, hence analysis on ethnicities and MetS in this study was very limited. It is also important to note the possibility that breast cancer survivors that agree to participate in this research might have more health-awareness compared to non-participants. Similarly, other important factors such as breast cancer subtype, physical activity and dietary intake were not reported in this study. Therefore, the links and their confounding effects on MetS could not be determined.To the best of our knowledge, this is the first study to report the prevalence of MetS among breast cancer survivors in East Coast of Peninsular Malaysia. MetS prevalence among breast cancer survivors in East Coast of Peninsular Malaysia was higher than normal population and in need of urgent attention. Therefore, in clinical settings, it is recommended to give utmost priority in improving triglycerides, blood glucose and HDL-c level of the breast cancer survivors in Malaysia to control MetS.Additional file 1: Supplementary Material Table 1. Relationship between characteristics of breast cancer survivors and metabolic syndrome.