Dementia is a chronic progressive neurodegenerative disease that can lead to disability and death in humans, but there is still no effective prevention and treatment. Due to the neuroprotective effects of vitamin E, a large number of researchers have explored whether vitamin E can reduce the risk of dementia. Some researchers believe that vitamin E can reduce the risk of dementia, while others hold the opposite conclusion. We therefore performed a meta-analysis to clarify the relationship between them.We searched PubMed, Embase, and Web of Science databases for articles on the connection of dietary and supplementation vitamin E with dementia risk from inception through April 2022 using the main keywords “dementia,” “Alzheimer's disease,” “vitamin E,” and “tocopherol,” and used a random-utility model for pooled effect sizes. Odds ratios (OR) and 95% confidence intervals were derived using lower and higher doses as contrasts. Obtained data were shown and assessed using Stata12.0 free software.I2 = 35.0%), Alzheimer's disease . Subgroup analyses were also performed by study type, diet and supplementation, and NOS score.We included 15 articles in sum. Among them, there were nine articles containing AD. By comparing the highest intake with the lowest intake, Combined ORs for high intake were as follows: dementia (OR = 0.79, 95% CI 0.70–0.88 High vitamin E intake from diet and supplements significantly reduces the risk of dementia and Alzheimer's disease. Dementia is a condition that causes gradual cognitive decline  guidelines. Two authors (Rangyin Zhao and Xiaoyong Han) conducted a paper search for the association of vitamin E and active ingredients with dementia risk using EMBASE, Web of Science and PubMed databases, respectively. The database was searched using keywords/titles/abstracts searching for the keywords: “vitamin E” or “alpha-tocopherol” or “α-tocopherol” or “nutrients” combined with “dementia” or “amentia” or “amentias” or “Alzheimer's Disease” or “Alzheimer Dementia” or “Alzheimer Dementias” or “Dementia, Alzheimer.” The search was conducted from inception to April 2022 for all relevant articles. In addition, we searched conference proceedings, meta-analyses, and references from other articles to avoid possibly missing research. We only included English literatures. Search disagreements between the two authors and a third author discuss decisions together.We developed the inclusion criteria for our study using PICOS principles. P (Participants): middle-aged and elderly population without dementia and cognitive impairment; I (intervention): high intake of vitamin E from diet or supplements; C (control): low intake of vitamin E from diet or supplements; O (outcome): risk of dementia. S (study design): case-control study or cohort study. Studies that met the following criteria were included: (1) patients with a definite diagnosis of dementia; (2) the type of study was a cohort or case-control study; (3) the association between diet or supplement vitamin E or tocopherol and the risk of dementia was studied and compared between high and low dose; (4) the study contained the following relevant data: relative risk (RR) or odds ratio (or) and 95% confidence interval; (5) the study subjects were humans, excluding experiments such as cells and animals. The exclusion criteria used were as follows: (1) no valid data could be extracted from the text; (2) duplicate study populations; (3) small sample size; (4) reviews, conferences, meta-analyses, letters, etc.Two researchers independently performed quality assessment and extraction of relevant data for all included studies. Basic information for inclusion included: first author name, date of publication, country, sex, age, type of dementia, type of study, Sample Size of Study, RR or OR and 95% CI adjustment for covariates in multivariate analysis. Discrepancies between the two authors were resolved by discussion with the other authors. The Newcastle-Ottawa Scale (0–9) was used to evaluate the quality of the literature used.p < 0.05 indicating a statistically significant difference.Effect sizes for all studies were RR or OR and 95% confidence intervals to analyze the connection of high-dose vitamin E or tocopherol intake with the risk of dementia. The effect sizes for assessing dementia risk were RR, OR for the cohort study and case-control study, respectively. Since the difference between the two effect sizes is small, the OR value is uniformly used to represent it for the convenience of combining and calculating the study results. We used a random-effects model to count effect sizes. The results of meta-analysis were presented as forest plots, and publication bias was assessed by Begg's test and funnel plots. In addition, sensitivity analysis assessed the stability of the meta-analysis by eliminating each study one by one. All statistical analyses were calculated using Stata12.0, with n = 1,105), Embase (n = 980), and Web of Science (n = 968). Two useful original articles were obtained by searching the citations of articles such as reviews or meta-analyses. After removing duplicates, 1,320 articles remained. Reviews, case reports, conferences, comments, letters, and irrelevant articles were excluded by reading the titles or abstracts, for a total of 1,252. The additional 68 essays have been assessed by downloading the full text and articles with missing raw data were excluded. The remaining 15 studies that met the inclusion criteria and NOS score were included in the meta-analysis. The above retrieval process is shown in Three thousand and fifty-three literatures were retrieved through three English database retrieval systems, which were PubMed . The heterogeneity was low . When subgroup analyzed by study type, cohort studies . The heterogeneity was low . Cohort studies .The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest.All claims expressed in this article are solely those of the authors and do not necessarily represent those of their affiliated organizations, or those of the publisher, the editors and the reviewers. Any product that may be evaluated in this article, or claim that may be made by its manufacturer, is not guaranteed or endorsed by the publisher.


I2 98.13%). Similarly, higher odds of association were found in patients taking SSRIs , NSAIDs  and Statins . No difference in odds of developing MC was seen in patients using H2RA compared to the control group . We performed a subgroup analysis based on the control group and found higher odds of MC in patients on PPIs compared to the random control group . Similarly, higher odds of MC were noted for SSRI , NSAIDs , and Statins  compared to the random control group. Contrary lower odds of MC were seen in the PPI and H2RA group compared to the diarrhea control group ,  respectively. We found no difference in odds of MC in patients on SSRIs , NSAIDs  Statins  and H2RA  compared to the diarrhea control group. We also analyzed the association use of PPIs and NSAIDs with the development of collagenous colitis (CC) and lymphocytic colitis. Only the use of NSAIDs was associated with increased odds of developing collagenous colitis . No increased odds of CC and LC were seen in PPI users. PPIs, NSAIDs, SSRIs, and Statins are associated with an increased risk of MC compared to the random control group. On the contrary, the use of PPIs, NSAIDs, SSRIs, and Statins is not associated with an increased risk of MC when compared to the diarrhea control group.There is growing evidence of the association of Microscopic Colitis (MC) with the use of specific medications such as proton pump inhibitors (PPIs), Selective serotonin reuptake inhibitors (SSRIs), Non-Steroidal anti-inflammatory drugs (NSAIDs), Statins and H2-receptor antagonists (H2RA). In our study, we calculated the pooled odds of MC in patients using these drugs. We performed a detailed search of major databases, including PubMed/Medline, Scopus, web of science, and Embase, to include the studies in which odds of MC were reported after using above mentioned drugs. A random-effects model was used to pool the estimates. Thirteen studies were included in our analysis consisting of 304,482 patients . In eight studies, the control group consisted of a random population selected based on age, gender and same birth year, whereas 3 studies recruited patients who presented with diarrhea and underwent colonoscopy and biopsy to rule out MC. Two studies reported odds of MC for both diarrhea and random control groups. Patients taking PPIs were more likely to develop MC, AOR 2.65 (95% CI 1.81–3.50,  Microscopic colitis (MC) is a chronic inflammatory disease of the large intestine, consistent with two histological subtypes, lymphocytic colitis (LC) and collagenous colitis (CC). The most common presentation of MC is chronic watery diarrhea associated with abdominal pain, fecal urgency, and incontinence ,2. MicroThe inflammation of the colon in response to luminal antigen exposure is suggested to underlie the mechanism of MC, but the exact pathogenesis is still unclear . EndoscoFemale sex and increasing age are the established risk factors associated with MC . There iIn our meta-analysis, we aimed to study the association of PPIs, SSRIs, NSAIDs, Statins, and H2RA with microscopic colitis. We further examined the association of PPIs and NSAIDs with subtypes of MC, including subgroup analysis for LC and CC. This is the first systematic review and meta-analysis on this topic to the best of our knowledge.We designed and performed an electronic literature search of Medline/PubMed, Embase Ovid, Cochrane Central Register for controlled trials, Scopus, and web of science from inception to 30 September 2022. We followed the preferred reporting items for the systematic review and meta-analysis (PRISMA) statement. Zahid Tarar (ZT) and Umer Farooq (UF) designed the search strategy, which was approved by Ebubekir Daglilar (ED). Both ZT and UF independently searched the databases mentioned above and registers. We designed three questions for our analysis. (1) Is there an association between medication use and microscopic colitis? (2) what are the odds of developing microscopic colitis in patients taking certain medications, including PPIs, SSRIs, NSAIDs, Statins, and H2RA? (3) what are the odds of developing collagenous and lymphocytic colitis in patients taking PPIs and NSAIDs? We included medical subject headings [Mesh] and free-text terms in our search. Following free text terms were used in different combinations: “(Microscopic colitis) AND (Drugs) OR (Medications) AND (Proton pump inhibitors) AND (PPIs OR SSRIs OR Statins OR H2RA OR NSAIDs) AND (Collagenous Colitis) AND/OR (Lymphocytic Colitis)”. All search fields were used in all databases and registers except in Scopus, where the “Article title, keywords, and abstract” field was used. We also hand-searched the reference list of included studies.We included the studies which meet the following criteria. (1) Reported odds of microscopic colitis in patients taking PPIs, SSRIs, NSAIDs, Statins, or H2RA; (2) Defined a control group; (3) Age above 18; (4): Reported odds of developing LC and CC while on PPIs or NSAIDs. p-value was provided; (2) Case reports or case series; (3) Abstracts or conference articles; (4) Letter to editors, Review articles and editorials; (5) Studies in which outcome data were missing; (6) Studies in a foreign language. Two investigators (ZT and UF) independently screened the abstracts, titles, and complete reports to identify the eligible studies based on pre-defined inclusion criteria. Any conflict or disagreement between the reviewers was resolved through discussion or by a third reviewer (MG). All references were downloaded in Endnote 11, and duplicate studies were removed manually and automatically.The following exclusion criteria were used (1) Studies in which odds ratios were not provided, or just Data were extracted into Microsoft excel by two reviewers (ZT and MT). They independently pulled the information about study design, first author, year of publication, country of study, study cohort characteristics , duration of the study, period of medication use, percentage of patients taking medications in both cases and control group, odds of developing MC in patients taking drugs, odds of developing CC and LC in patients taking PPIs or NSAIDs. We did not conduct an analysis on the odds of LC and CC for stains, SSRIs, and H2RA due to a lack of data availability. Once data was extracted, a third reviewer (ED) independently reviewed the extracted data sheet, and the final data sheet was prepared after discussion.p-value < 0.05 was considered statistically significant. Cochrane chi-square test and I2 statistics were used to test heterogeneity. Heterogeneity of 0, 25%, 50% and 75% were interpreted as absent, low, moderate and high, as described by the Cochrane Handbook for Systematic review [We calculated the pooled odds ratio from each study’s reported adjusted odds ratios. A random-effects model was used to calculate the pooled Odds ratio with 95% CI, and c review . Forest In contrast, three studies ,9,12 useI2 98.13%). On subgroup analysis, lower odds of MC  were found compared to the diarrhea control group, while greater odds were seen compared to the random control group . A statistically significant difference was seen between the groups (p < 0.0001)  .I2 96.46%). We included nine different odds ratios from 8 studies [I2 98.31%), whereas on the contrary, no difference in odds of MC was noted in comparison to the diarrhea control group   .I2 92.70%). On subgroup analysis based on the control group, we found higher odds of MC in patients taking NSAIDs in comparison to the random control group , whereas no difference in odds of MC was noted when compared to the diarrhea control patient group . A statistically significant difference was noted between these two groups p (0.001)  .I2 96.36%) calculated from 9 adjusted odd ratios obtained from 7 studies [I2 98.11%). No significant difference in odds of MC was found in statin users compared to the diarrhea control group   .I2 98.67%) based on the data provided in four studies [I2 0%). Similar odds of MC were seen compared to the community control patient population . No significant difference was seen between the groups (p 0.13)  .I2 99.28%),  respectively were seen in patients taking PPIs compared to control group. No statistically significant difference was seen between both groups (p 0.42). Odds of CC  were significantly higher in patients on NSAIDs, whereas similar odds of LC were found in NSAIDs users  compared to the control group. No significant difference between the CC and LC groups was seen (p 0.25)  A,B.We evaluated the quality of included studies using the Methodological Index for Nonrandomized Studies (MINORS) criteria . MINORS Visible asymmetry was noted on funnel plots, but the nonparametric trim and fill test was negative for any publication bias .In our analysis, we reported the effect of medication use on the development of microscopic colitis. We demonstrated that certain medications such as proton pump inhibitors, SSRIs, NSAIDs, and Statins are associated with an increased risk of MC, but H2RA use was not associated with an increased risk of MC when compared to random control groups. This is the first meta-analysis on this topic to the best of our knowledge, and the results of our analysis are significant.Our results showed that using PPIs is associated with significantly higher odds of MC, in accordance with the results of the previous studies ,18,19,21Data on the association of MC with the use of H2RA is conflicting. As the effect of H2RA on acid secretion is like PPIs, it is thought that they can cause intestinal dysbiosis, leading to MC. Our analysis did not find increased odds of MC in patients taking H2RA. A recent study by Zylberberg et al.  reportedThe NSAIDs inhibit prostaglandin synthesis, which results in increased gut permeability and impairs the integrity of the mucosal barrier resulting in an influx of bacteria and toxins into the intestinal lumen. The reaction to these luminal antigens is considered an underlying pathogenetic factor for the development of MC in NSAID users ,28. We rWe demonstrated greater odds of MC in statin users, which is consistent with the results reported in the studies performed earlier ,17,18,19The effect of SSRI on the causation of MC is not well studied, although a few factors which have been considered potential contributors and reported in the literature are the following. First, it is said that serotonin possesses inflammatory characteristics, as seen in cases of colitis . MoreoveOur study has several strengths. We conducted a detailed literature search of all the major database engines and a manual search of the bibliography of included studies. Two investigators searched and screened the databases separately, and a third reviewer approved the final studies included in the analysis. We emailed the primary and corresponding authors to get any missing information and avoid duplication of results. We performed a subgroup analysis based on control groups to prevent overestimating the effects from reports where healthy controls were recruited. We used a random-effect model to provide a more conservative and generalized pooled odds of MC in patients on different medications. We also did a sensitivity analysis to minimize the effect of any study affecting the results. Moreover, this is the first meta-study analyzing the association of MC with a particular medication.There are a few limitations of our meta-analysis. The first few studies used random healthy controls as a comparison. In contrast, in other studies, diarrhea controls were recruited, leading to an overestimation of results due to differences in medication exposure between both control groups. Second, drug dosage was not provided in most of the included reports. Furthermore, it was not clearly stated if a patient was taking two medications which can result in MC at the time of the study. Moreover, only a few studies separately provided LC and CC odds. In addition, many reported medications are available over the counter in many countries where these studies are performed, so noted exposure can be overestimated or even underestimated.


The preventive effect of cholesterol efflux capacity (CEC) on the progression of atherosclerotic lesions has been confirmed in animal models, but findings in the population are inconsistent. Therefore, this meta-analysis aimed to systematically investigate the relationship of CEC with coronary artery disease (CAD) and cardiovascular mortality in a general population.Four electronic databases  were searched from inception to February 1st, 2022 for relevant studies, without any language restriction. For continuous variables, the mean and standard deviation (SD), maximum adjusted odds ratios (ORs), relative risks (RRs), or hazard ratios (HRs) and 95% confidence intervals (CIs) were extracted. The random-effects model was adopted to calculate the pooled results, and dose-response analyses were conducted. All pooled results were expressed by standardized mean difference (SMD) and ORs.2 88.9%) had significantly lower CEC. In the high-CEC population, the risks of CAD  significantly decreased, and a linear negative dose-response was detected. However, an association between CEC and the risk of cardiovascular mortality was not found .Finally, 18 observational studies were included. Compared with the non-CAD group, the CAD group (SMD -0.48, 95% CI − 0.66 to − 0.30; IThis meta-analysis suggests that decreased CEC is strongly associated with the risk of CAD, independent of HDL-C level. However, a decreased CEC seems not to be related to cardiovascular mortality. Meanwhile, CEC is linearly negatively correlated with the risk of CAD.The online version contains supplementary material available at 10.1186/s12944-022-01657-3. Coronary artery disease (CAD), a manifestation of atherosclerosis, results in stable angina, unstable angina, myocardial infarction (MI), or sudden cardiac death . CurrentRCT is the process where excess cholesterol is transported via HDL from peripheral tissues to the liver and ultimately to the bile and feces for excretion . In 1975To verify this hypothesis, several trials based on statin therapy, cholesteryl ester transfer protein (CETP)-inhibitors and niacin have been conducted, but their results are unsatisfactory –17. FurtThus, the research focus has shifted towards HDL functionality rather than quantity. Cholesterol efflux capacity (CEC) indicates the ability of HDL to facilitate the removal of cholesterol from the lipid-filled macrophages . CEC depThis study protocol and report were based on the “Preferred Reporting Items for Systematic Reviews and Meta-Analyses” (PRISMA) statement  and wereThe exposure of interest was HDL-CEC. All studies reporting CEC were included, regardless of the specific laboratory or calculation methods. According to the definitions of the included original studies, CAD was defined as coronary stenosis ≥50% confirmed by coronary angiography or multi-slice coronary computed tomography, or history of myocardial infarction or angina confirmed by hospital or autopsy records. Cardiovascular mortality was defined as death due to any cardiovascular cause or sudden cardiac death. In this study, our endpoints included CAD and cardiovascular mortality risk.studies conducted on the general population with the age over 18 years;studies, whose exposure of interest was HDL-CEC;the CEC values of non-CAD population in case-control studies were regarded as the control group;the CEC values in cohort studies were divided by medians or into quartiles, and patients with the lowest CEC quartile or those with CEC below the median were enrolled into the reference group according to the calculation method of original publications;studies, that reported the risk of CAD or cardiovascular mortality;studies, that were limited to case-control, cohort studies, or randomized controlled trials;studies reporting relevant effect values such as odds ratios (ORs), relative risks (RRs), or hazard ratios (HRs) together with respective 95% confidence intervals (CIs).With reference to the PICOS  criteria , the stustudies focusing on cancer, autoimmune diseases, familial hyperlipidemia, or renal failure;studies where the HDL-CEC values could not be obtained or converted;studies not reporting the risk of CAD or cardiovascular mortality;cross-sectional studies;studies with unavailable ORs, RRs, or HRs;conference abstracts, case reports, or case series.The study exclusion criteria were:A uniform list was prepared to collect related baseline characteristics, including first author, year of publication, country, sample size, proportion of males, age of patients on inclusion, follow-up, subjects, endpoints, donor cell line, labeled cholesterol, and cholesterol acceptor. In addition, the maximum covariate-adjusted ORs, RRs, or HRs were extracted. The quality of the included studies was assessed using the Newcastle Ottawa Scale (NOS), with a total score of 9 stars . StudiesFirstly, we assessed the difference in CEC value between CAD and non-CAD populations. For this purpose, the sample numbers, mean CEC values, and SD of CEC in CAD and non-CAD groups were extracted from the selected studies. Considering the heterogeneities in the experimental measurement methods, the standardized mean difference (SMD) was utilized for assessment. For studies reporting median values and interquartile ranges, with a large sample size (> 100/group), the median values were treated as means, and SD was calculated by 75th minus 25th percentiles divided by 1.35 , otherwi2 statistic, where I2 values of 25, 50, and 75% indicated low, moderate, and high inconsistencies, respectively [n ≥ 10) were included [Secondly, we assessed the difference in cardiovascular risk between the highest and the lowest CEC value groups. In cohort studies, CEC values were divided according to quartiles or medians, where the quartile 1 (Q1) or less-than median group was regarded as the lowest group, while the quartile 4 (Q4) or over median group as the highest group. Broadly speaking, the differences between the different effect values  were very minor if the incidence of the outcome is low (< 10%) . The cumectively . If therincluded , Begg’s p-values were calculated by testing whether the coefficient of the second spline was equal to zero. When the nonlinear p-value was < 0.05, the nonlinear model was adopted; otherwise, the linear model was adopted. Furthermore, when studying open intervals, the amplitudes were assumed to be the same as the adjacent categories. All statistical analyses were conducted using the statistical program Stata 12.0E.Thirdly, this study focused on assessing the dose-response analyses between CEC and cardiovascular outcomes. To maximize the available studies, the robust error meta-regression approach proposed by Xu and Doi  was empln = 8); b) studies not reporting CEC (n = 12); c) studies not including the risk of CAD or cardiovascular mortality (n = 14); d) cross-sectional studies (n = 4). Further, a “snowball search” was performed based on the citation list of all included studies. In the 18 studies initially identified, there were 614 citations, whereas 523 were irrelevant for this meta-analysis, 55 were duplicates, and 36 were reviews. Ultimately, no additional studies were included in the analysis. The detailed flow chart of the study retrieval process is presented in Fig. Initially, a total of 2524 studies were identified from the four databases. Among them, 646 records were identified more than once and consequently excluded, leaving 1878 studies. After screening the titles and abstracts of these 1878 studies, 1814 were excluded due to irrelevance, and 8 studies were excluded because of being not retrievable, leaving 56 studies for full-text review. Finally, 18 observational studies were included for the present meta-analysis. The specific reasons for study exclusion were as follows, a) reviews   detected by Begg’s test, whereas Egger’s tests suggested that there might be a publication bias (p = 0.007). Trim and fill analyses were thereby conducted because there were no additional studies. The pooled results obtained from the random model were the same.CEC values of CAD group were significantly lower than those of non-CAD group  Fig. . Moreove2 = 81%), and similar results were obtained after subgroup analysis by OR  and HR . Similarly, the risk of CAD decreased by 19% per 1-SD CEC increment , and similar results were observed from the subgroup analysis according to OR  and HR   or Egger’s test (p = 0.283).The risk of CAD decreased by 48% in the highest CEC group compared with the lowest CEC group , similar results were obtained after subgroup analysis by HR . However, when the study by Ritsch et al. (the incidence of outcome was 18%>10%) was removed, the pooled results showed a weak correlation  . CEC values were significantly lower in the CAD group compared to the non-CAD group. 2). The reduced CEC values were significantly associated with the risk of CAD. 3). There was no significant correlation between CEC values and the risk of cardiovascular mortality.To the best of our knowledge, four previous systemic reviews and meta-analyses have systematically investigated the relationship of HDL-CEC with cardiovascular disease (CVD) –50. Our HDL may delay the formation of atherosclerotic lesions through various mechanisms . It is wFurther, HDL-CEC can exert anti-inflammatory and anti-atherosclerotic effects by inhibiting inflammatory processes in macrophages and activation of the inflammasome . In thisAlthough CEC is a key indicator for the anti-atherosclerotic function of HDL and a strong predictor for CAD outcomes, measurement of HDL-CEC is not a part of routine lipid tests in CVD patients. This is partly explained by the lack of standardized procedures and the complexity of CEC mechanisms, because cholesterol efflux involves plenty of enzymes, like ATP-binding cassette transporter A1 (ABCA1), ATP-binding cassette transporter G1 (ABCG1), scavenger receptor class-BI (SR-BI), and aqueous diffusion . MeanwhiCompared to previous studies, the present study has the following strengths. To our knowledge, this is the first meta-analysis that systematically analyzes the association of CEC with the risks of CAD and cardiovascular mortality by dose-response analyses., where the incidence of cardiovascular mortality was exceptionally high (18%). This might be explained by the comparably long follow-up period (approximately 10 years) and the advanced age of the population. Except for the study by Ritsch et al., the other included cohort studies had a low incidence of cardiovascular outcomes (< 10%). Besides, although all the effect values of ORs/RRs included in this analysis were adjusted for covariates by the original authors . The search and screening of this paper were done by the first author twice in July 2021 and February 2022, respectively. No kappa statistics were prepared. 2). There were high heterogeneities in the pooled cohorts used to generate the results of this paper, representing a limitation of this study. Heterogeneity is a consequence of the variability in experimental procedures, methods, study quality, and the differences in the characteristics of the studied patients. To address this problem, the donor cell line, labeled cholesterol, and cholesterol acceptors were identified as the possible sources of heterogeneity through subgroup analyses. Future experiments should consider the potential impact of experimental materials on the study. 3). Due to the insufficient number of existing studies, some pooled results were not further analyzed by subgroup analyses to detect the potential sources of heterogeneity. 4). A high percentage of patients were from the study by Ritsch et al.Based on the current evidence, we suggest that a decreased CEC is strongly associated with the risk of CAD, independent of HDL-C level. However, a decreased CEC seems not to be related to cardiovascular mortality. In addition, CEC is negatively correlated with the risk of CAD in a linear manner. Nonetheless, further multi-center, multi-regional, and large sample studies are warranted in the future to complement and further validate these findings.Additional file 1: Supplementary Figure 1. The sensitivity analyses of CEC difference in coronary artery disease (CAD) and non-CAD group. CEC, cholesterol efflux capacity. The figure depicts pooled results of random-effect meta-analyses considering the remaining studies after excluding named study. Supplementary Figure 2. The funnel of CEC difference in coronary artery disease (CAD) and non-CAD group. CEC, cholesterol efflux capacity. Supplementary Figure 3. A The sensitivity analyses of CEC and the risk of coronary artery disease (CAD). CEC, cholesterol efflux capacity. The figure indicates the pooled results of the remaining studies after excluding named study (Study of Li MX includes two cohort). B. The sensitivity analyses of CEC and CAD risk by per 1-SD increasement. CEC, cholesterol efflux capacity. SD, standard deviation. Supplementary Figure 4. The funnel of CEC and CAD risk. CEC, cholesterol efflux capacity. CAD, coronary artery disease. Supplementary Figure 5. The sensitivity analyses of CEC and the risk of cardiovascular mortality. CEC, cholesterol efflux capacity. Supplementary Table 1. Subgroup Analyses. Supplementary Table 2. Quality Assessment of the 18 observational Studies. Supplementary Table 3. Characteristics of 18 Observational Studies.


HIF1A gene polymorphisms have been confirmed the association with cancer risk through the statistical meta-analysis based on single genetic association (SGA) studies. A good number SGA studies also investigated the association of HIF1A gene with several other diseases, but no researcher yet performed statistical meta-analysis to confirm this association more accurately. Therefore, in this paper, we performed a statistical meta-analysis to draw a consensus decision about the association of HIF1A gene polymorphisms with several diseases except cancers giving the weight on large sample size. This meta-analysis was performed based on 41 SGA study’s findings, where the polymorphisms rs11549465 (1772 C/T) and rs11549467 (1790 G/A) of HIF1A gene were analyzed based on 11544 and 7426 cases and 11494 and 7063 control samples, respectively. Our results showed that the 1772 C/T polymorphism is not significantly associated with overall disease risks. The 1790 G/A polymorphism was significantly associated with overall diseases under recessive model (AA vs. AG + GG), which indicates that the A allele is responsible for overall diseases though it is recessive. The subgroup analysis based on ethnicity showed the significant association of 1772 C/T polymorphism with overall disease for Caucasian population under the all genetic models, which indicates that the C allele controls overall diseases. The ethnicity subgroup showed the significant association of 1790 G/A polymorphism with overall disease for Asian population under the recessive model (AA vs. AG + GG), which indicates that the A allele is responsible for overall diseases. The subgroup analysis based on disease types showed that 1772 C/T is significantly associated with chronic obstructive pulmonary disease (COPD) under two genetic models (C vs. T and CC vs. CT + TT), skin disease under two genetic models (CC vs. TT and CC + CT vs. TT), and diabetic complications under three genetic models , where C allele is high risk factor for skin disease and diabetic complications , but low risk factor for COPD . Also the 1790 G/A variant significantly associated with the subgroup of cardiovascular disease (CVD) under homozygote model, diabetic complications under allelic and homozygote models, and other disease under four genetic models, where the A is high risk factor for diabetic complications and low risk factor for CVD. Thus, this study provided more evidence that the HIF1A gene is significantly associated with COPD, CVD, skin disease and diabetic complications. These might be the severe comorbidities and risk factors for multiple cancers due to the effect of HIF1A gene and need further investigations accumulating large number of studies. HIF1A), a transcription factor, has been a research focus to explain its role in oxygen sensing under normal and hypoxic conditions. Many aspects of Human physiology need to match oxygen supply to cellular metabolism and presumably regulate gene expression by sensing oxygen ; ; ; ; and   under two genetic models  and . However, the subgroup analyses of autoimmune diseases, inflammation, preeclampsia, CVD, T2D and other showed insignificant association with the HIF1A 1772 C/T polymorphism.The subgroup analyses results based on disease type showed that the HIF1A 1772 C/T polymorphism exhibited that this polymorphism was strongly associated with overall disease risk in Caucasian populations under all genetic models ; ; ; ; and . This polymorphism showed a low significant association with overall disease risk in mixed population under dominant model  and insignificant association for Asian patients.The subgroup analyses by ethnicity for the HIF1A 1772 C/T polymorphism with overall disease risk under the four genetic models: ; ; ; and . Also in subgroup analysis, some genetic model showed the significant heterogeneity in cases of autoimmune disease, inflammatory disease, CVD, skin disease, T2D disease group and Asian, Caucasian and mixed ethnic populations  to assess whether associations reported previously were false positives. We preset FPRP at 0.2 as the threshold for biological importance and a prior probability ‘π’ at 0.01 to detect the significant OR . We compHIF1A gene polymorphisms with multiple diseases risks more accurately compare to SGA studies. This analysis was performed based on 41 SGA study’s findings, where the polymorphisms rs11549465 (1772 C/T) and rs11549467 (1790 G/A) of HIF1A gene were analyzed based on 11544 and 7426 cases and 11494 and 7063 control samples, respectively. This study included different types of diseases  and ethnic groups  were considered in this meta-analysis. The allelic alterations in different ethnic population and their association with diseases were carefully evaluated using five different genetic models (i) dominant models: CC + CT vs. TT or AA + AG vs. GG, (ii) homozygote models: CC vs. TT or AA vs. GG, (iii) heterozygote models: CT vs. TT or AG vs. GG, (iv) recessive models: CC vs. CT + TT or AA vs. AG + GG, and (v) allelic contrast models: C vs. T or A vs. G, for each of 1772 C/T and 1790 G/A polymorphisms. The results of this study suggested that the HIF1A 1772 C/T polymorphism is insignificantly associated with overall disease risks under all the genetic models, which indicates that the C allele is not associated with overall diseases. The HIF1A 1790 G/A polymorphism showed a significant association with overall disease under the recessive model (AA vs. AG + GG), which indicates that the A allele is associated with overall diseases though A was recessive. The subgroup analysis based on ethnicity showed significant association between the HIF1A 1772 C/T polymorphism and overall disease for the Caucasian population under the all genetic models, which indicates that the C allele is associated with overall diseases. Again, the ethnicity subgroup showed a significant association between HIF1A 1790 G/A polymorphism and overall disease for the Asian population under recessive model only (AA vs. AG + GG), which indicates that the A allele is associated with overall diseases. The subgroup analysis based on disease type showed that HIF1A 1772 C/T is significantly associated with COPD, skin and diabetic complications diseases, where C is high risk factor for skin and diabetic complications , but low risk factor for COPD . This subgroup analysis results goes in favor of Ekberg et al. [HIF1A 1772 C/T polymorphism showed insignificant association with autoimmune diseases, inflammatory diseases, and preeclampsia under all five genetic models which goes in favor of Wipff et al. [HIF1A 1790 G/A polymorphism showed significant association with CVD under homozygote model (AA vs. GG) and diabetic complications under allelic (A vs. G) and homozygote (AA vs. GG) models. Also, the HIF1A 1790 G/A polymorphism showed significantly decreasing the risk of other  disease group under four genetic models  and insignificant association with inflammatory disease, COPD, autoimmune disease and preeclampsia under all genetic models. The association of diabetic complications contradicted the reports by Ren et al. [HIF1A 1790 G/A were supported by Bahadori et al. [We performed a statistical meta-analysis to investigate the association of g et al.  for diab11549465 72 C/T ang et al.  for COPDg et al. . Also thf et al.  and Fengf et al.  for autof et al. , Chachamf et al.  and Senhf et al.  for preen et al. . The insi et al. , Chachami et al. , Senhajii et al.  for infli et al.  for lungi et al.  for preeHIF1A gene is a risk factor for the development of COPD, CVD, skin disease and diabetic complications. Now it is required to explore the causality of HIF1A gene SNPs (1772 C/T and 1790 G/A) in the development of those disease by their expression analysis. Recently, some researchers studied single or multiple disease causing genes or SNPs by using network analysis or Mendelian randomization [cis-acting factors, and they may play a more direct role in disease development by affecting the gene’s function. When SNPs occur far away from the disease causing genes, they are known as trans-acting factors. The cis- and trans-acting factors are usually considered as the causal and non-causal risk factors of disease development, respectively. SNPs can be silent due to its occurrence within the noncoding regions or may change the encoded amino acids due to its occurrence within the coding region. They may influence promoter or enhancer activities, messenger RNA (mRNA) stability, and subcellular localization of mRNAs and/or proteins and hence may develop disease. A post-transcriptional modification (PTM) in mRNA, known as N4-acetylcytidine (ac4C) that occurs on cytidine, plays a vital role in the stability and regulation of mRNA translation. There are at least 15 nucleotide modifications found in mRNA of which m6A and N1-methyladenosine (m1A) are similar in function to ac4C. They play a significant role in the translation process of mRNA and its stability that leads to the progression of several human diseases [Thus the above discussion provided the significant evidence that the mization –82. Thesmization . When SNdiseases –87.HIF1Agene data are available for COPD, CVD, skin disease and diabetic complications, and control samples, an effective disease prediction model may be developed by using a suitable machine learning technique including logistic classifier. For example, some recent studies developed SNPs based diseases prediction model [If SNPs (1772 C/T and 1790 G/A) of on model , 89.However, there were some limitations in this study, such as (i) the heterogeneity factors such as gender, age, smoking, drinking, blood pressure, family history, etc was not considered to estimate the combined effect for overall or subgroup analysis like as –60. BecaHIF1A gene polymorphisms with multiple diseases risks excluding cancers. The meta-analysis results showed that the HIF1A 1772 C/T polymorphism is not significantly associated with overall disease risks The HIF1A 1790 G/A polymorphism was associated with overall diseases under recessive model, where the allele A controls the diseases though it is recessive. The ethnicity subgroup analysis showed the significant association of HIF1A 1772 C/T polymorphism with overall disease for Caucasian population under all genetic models, where C allele controls the diseases, while HIF1A 1790 G/A polymorphism was significantly associated with overall disease for Asian population under a genetic model due to the influence of A allele. The subgroup analysis based on disease types showed that HIF1A 1772 C/T is significantly associated with chronic obstructive pulmonary disease (COPD), skin and diabetic complications diseases, where C allele is the high risk factor for skin and diabetic complications diseases, and low risk factor for COPD. The HIF1A 1790 G/A polymorphism showed significant association with CVD under homozygote model and diabetic complications under allelic and homozygote models. The rest of diseases showed insignificant association with HIF1A gene under all of five genetic models by the subgroup analysis. Taken together, the results of this study suggest that HIF1A could be a useful prognostic biomarker for COPD, CVD, skin disease and diabetic complication diseases. In future, availability of more SGA studies on the different ethnic populations might shed more lights to unveil and confirm the association of the HIF1A gene polymorphisms with different diseases.In conclusion, this study made a consensus decision about the association of S1 Checklist(DOCX)Click here for additional data file.S2 Checklist(DOCX)Click here for additional data file.S1 Data(XLSX)Click here for additional data file.S2 Data(XLSX)Click here for additional data file.S1 Table(DOCX)Click here for additional data file.S2 Table(DOCX)Click here for additional data file.S3 Table(DOCX)Click here for additional data file.S4 Table(DOCX)Click here for additional data file.S1 File(DOCX)Click here for additional data file.


The treatment of atrial fibrillation (AF) has made significant progress, but the prevention of AF has not received the attention it deserves. A few recent large-sized studies have conducted dose response analysis and reported different conclusions from previous studies on alcohol consumption and AF risk.The aim of this study is to examine the potential non-linear association between alcohol consumption and risk of AF and explore the potential differences of gender.In this updated dose-response meta-analysis, PubMed, Embase and Cochrane databases were searched until June 2022. Risk estimates were reported as relative risk (RR) with 95% confidence intervals (CIs). The random-effects restricted cubic spline models are used to evaluate the potential non-linear association between alcohol consumption and AF risk.p = 0.87) while a J-shaped curve was observed in women (p = 0.00). Regional subgroup analysis yielded broadly comparable results in Americas , Europe  and Asia .A total of 10,151,366 participants with 214,365 cases of AF enrolled in 13 prospective studies. The overall meta-analysis showed that a 1 drink/day increase in alcohol consumption increased the risk of AF by 6% . In gender subgroup analysis, pooled results were different between men  and women . A linear relationship between alcohol consumption and risk of AF was found in men (The relationship between AF risk and alcohol consumption is linear in men, while a potential non-linear J-shaped relationship is shown in women.We conducted a dose-response meta-analysis on the relationship between alcohol consumption and risk of atrial fibrillation. We merged the data of over 10 million participants and found gender differences in the pattern of association with AF and alcohol consumption. The relationship between AF risk and alcohol consumption is linear in men, while a potential non-linear J-shaped relationship is shown in women. In summary, this research is vital in furthering our understanding of the role of alcohol consumption in new-onset AF, especially among different genders. As the most common clinical arrhythmia, Atrial fibrillation (AF) is influencing over 34 million people worldwide with the increase of risk of stroke, heart failure (HF) and dementia , 2, resuThere have been several publications –8 by farThis paper performed an updated dose-response meta-analysis of prospective studies to examine the potential non-linear association of alcohol consumption with the risk of AF and explore the potential gender differences.This meta-analysis was conducted based on the guidelines for the Meta-Analysis Of Observational Studies in Epidemiology (MOOSE) .The literature of electronic databases  was methodically and comprehensively searched for eligible studies up to June 2022. The following search strategies were used to retrieve articles in English: ‘atrial fibrillation’ and ‘alcohol’. Further manual collection of references attached to retrieved articles was performed to identify other pertinent studies.The selection was based on the following inclusion criteria: (1) prospective design; (2) at least three types of alcohol consumption were reported; (3) numbers of participants and cases in each type of alcohol consumption were reported; (4) the adjusted relative risk (RR) and the corresponding 95% confidence interval (CI) of incident AF in each type of alcohol consumption were reported.After an electronic search of studies, the retrieved articles were selected with analysis of the title, abstract and full texts progressively according to inclusion criteria. The characteristics and data collected from eligible studies included: author, country, year, sex, age, number of cases and participants, follow-up duration, and types of alcohol consumption.Quality assessment criteria were used to evaluate the quality of eligible studies based on the Newcastle-Ottawa scale (NOS) . The sca2 statistic was adopted to evaluate the heterogeneity among eligible studies with 25, 50, and 75% representing low, moderate, and high heterogeneity, respectively . Sensitivity analysis (p = 0.07) suggested no evidence of publication bias. In subgroup analysis (p = 0.7) (p = 0.87) (p = 0.00) with a higher risk of AF at alcohol consumption more than 1.4 drinks/day  . There wanalysis  indicateanalysis  and Eggeanalysis , pooled p = 0.7) . A simil = 0.87) . Howeverinks/day . Regionainks/day .This study is an updated dose-response meta-analysis for evaluating the association between AF risk and alcohol consumption. Considering the shortcomings of previous meta-analyses –11, 14, In total, our results showed a 6% increase in AF risk for per drink one day, which is inconsistent with three previous meta-analyses –11, but Alcohol may contribute as a trigger of AF and long-term regular consumption promotes progressive atrial remodeling . Acute aThe protective effect of drinking (less than 1.4 drinks/day) in women needs further validation. There may be a variety of reasons for the observed gender difference in this study. Firstly, different dose-response associations may be related to different types of alcoholic beverage consumption. Ethanol and polyphenols in wine may be synergistic, thereby reducing the risk of chronic cardiovascular disease (CVD) . It was As for the regional subgroup, there was not enough data for a dose-response analysis. Some researches , 39, 40 The sample size of more than 10 million is the advantage of meta-analysis in this study, providing high statistical capacity to detect the relationship between AF risk and alcohol consumption. Moreover, all eligible studies are designed prospectively to minimize the likelihood of selection bias and recall bias. Nevertheless, there are also some limitations in this meta-analysis that may affect conclusions. First, although no statistical evidence of publication bias was detected, the likelihood of publication bias cannot be excluded due to the small number of studies. Second, there was moderate heterogeneity in preliminary meta-analysis, which needs to be considered when interpreting the results. The lack of corresponding exposure data prevented us from addressing the moderate heterogeneity. Third, due to the complex mechanism of AF, it is difficult to guarantee that our results are not affected by other confounding factors.In summary, this study provides further information about the role of alcohol consumption in new-onset AF, particularly between different genders. Regrettably, it is difficult to give a recommended amount of alcohol intake to prevent AF based on the current data.The relationship between AF risk and alcohol consumption is linear in men, while a potential non-linear J-shaped relationship is shown in women. An individual participant data meta-analysis of harmonized data across individual studies could help address some of the uncertainties in the shape of the relationship between different types of alcohol consumption and AF risk.The original contributions presented in this study are included in the article/supplementary material, further inquiries can be directed to the corresponding authors.HJ, XM, and YJ contributed equally to the study. XM conceived of the presented idea. HJ interpreted the data being published and made figures. HJ and YJ wrote the manuscript with support from XM, JY, and JS. TC and YZ revised the manuscript. All authors contributed to the article and approved the submitted version.


Variability of HbA1c has been related to the incidence micro and macrovascular complications in patients with diabetes. However, the association between of visit-to-visit variability of HbA1c and risk of dementia has not been fully determined. A meta-analysis was performed to comprehensively evaluate the above association.  Medline, Embase, and Web of Science databases were searched for longitudinal follow-up studies comparing the incidence of dementia in diabetic patients with higher or lower variability of HbA1c. A random-effect model incorporating the potential heterogeneity among the included studies were used to pool the results. p=0.04; I2 = 47%) and standard deviation  of HbA1c in continuous variables, and CV of HbA1c  in categorized variables.  Five retrospective studies with 577592 diabetic patients were included, and 99% of them were with type 2 diabetes mellitus (T2DM). With a mean follow-up duration of 6.3 years, 31963 patients had newly diagnosed dementia. Pooled results showed that diabetic patients with higher HbA1c variability was associated with higher risk of dementia, as evidenced by studies with coefficient of variation (CV: hazard ratio (HR): 1.06; 95% confidence interval (CI): 1.003–1.120;  Higher variability of HbA1c is associated with a higher incidence of dementia in patients with diabetes. Accumulating evidence suggests that diabetes may be a risk factor for cognitive impairment, and diabetes has been associated with higher risk of dementia –3. ConveThe meta-analysis was performed in accordance with the MOOSE   and CochStudies were identified via systematic search of electronic databases of PubMed, Embase, and Web of Science via the following terms: (1) “glycemic” OR “glyceamic” OR “glucose” OR “hemoglobin A1c” OR “A1C” OR “HbA1c”; (2) “variability” OR “variation” OR “fluctuation”; and (3) “dementia” OR “cognitive decline” OR “cognitive impairment” OR “cognitive dysfunction” OR “cognition” OR “Alzheimer” OR “Alzheimer's.” The search was limited to human studies published in English. The reference lists of related original and review articles were also analyzed using a manual approach. The final literature search was performed on August 21, 2021.The inclusion criteria for the studies were as follows: (1) designed in longitudinal follow-up studies, including cohort studies, post hoc analysis of clinical studies, and nested case-control studies; (2) included patients with confirmed diagnosis of diabetes, including type 1 and type 2 diabetes mellitus (T1DM and T2DM); (3) visit-to-visit HbA1c variability was evaluated at baseline and quantified via the CV or SD of HbA1c; (4) evaluated the association between glycemic variability and incidence of dementia during follow-up; and (5) reported the hazard ratio (HR) for the above association with CV or SD of HbA1c analyzed as continuous variables (per 1-SD increment) or categorized variables (highest versus lowest category). Reviews, editorials, cross-sectional studies, studies with nondiabetic patients, studies evaluating acute glycemic variability, or studies irrelevant to the aim of current meta-analysis were excluded.Literature search, data extraction, and quality assessment of the included studies were independently performed by two authors according to the predefined criteria. Discrepancies were resolved by consensus or discussion with the corresponding author. The extracted data included the name of first author, publication year, and country where the study was performed; study design characteristics; patient characteristics, including diagnosis of the patients, sample size, mean age, and sex; exposure characteristics, including parameters used for measuring of HbA1c variability at baseline (HbA1c-CV and/or HbA1c-SD), period for HbA1c variability calculation, and methods for HbA1c variability analysis; follow-up durations and outcomes reported; and confounding factors that were adjusted. The quality of each study was evaluated using the Newcastle-Ottawa Scale  which rap values and were logarithmically transformed to stabilize variance and normalized the distribution [Q test and estimation of I [I [p value < 0.05 indicates a statistical significance. We used the RevMan  and Stata software for the meta-analysis and statistics.We used HRs and their corresponding 95% confidence intervals (CIs) as the general measure for association between HbA1c variability at baseline and incidence of dementia during follow-up. Data of HRs and their corresponding stand errors (SEs) were calculated from 95% CI or ribution , 23. Cocion of I . A signi of I [I . Sensiti of I [I . A p valThe process of database search is shown in The characteristics of the included studies are given in p=0.04; p for Cochrane's Q test = 0.13, I2 = 47%). Sensitivity by excluding the study reporting AD-related dementia [p=0.04; I2 = 61%). Pooled results of two studies [p=0.002; p for Cochrane's Q test = 0.76, I2 = 0%). Moreover, pooled results of three studies [p < 0.001; p for Cochrane's Q test = 0.23, I2 = 31%). Sensitivity by excluding the study reporting AD-related dementia [p < 0.001; I2 = 0%).Pooled results of four studies , 17–19 sdementia  showed c studies  showed t studies , 16, 19 dementia  also shoThe funnel plots for the meta-analysis of the association between HbA1c variability and dementia risk as evaluated by HbA1c-CV and HbA1c-SD as continuous variable and HbA1c-CV as categorized variable are shown in Figures In this meta-analysis, we pooled the results of five retrospective follow-up studies, and the results showed that higher visit-to-visit variability of HbA1c may be independently associated with higher risk of dementia in patients with diabetes. The robustness of the finding was validated by consistent results of meta-analyses with the variability of HbA1c analyzed as HbA1c-CV and HbA1c-SD as continuous variables and HbA1c-CV as categorized variables. These results suggested that besides persistent hyperglycemia and hypoglycemia episodes, increased long-term glycemic fluctuation may also be an independent risk factor for dementia in patients with diabetes.As far as we know, this study is the first meta-analysis which summarized current understanding regarding the association between HbA1c variability and incidence of dementia in patients with diabetes. Before the interpretation of the results, some strengths of the meta-analysis should be highlighted. First, all of the included studies were longitudinal follow-up studies, which could therefore provide a temporal relationship between higher visit-to-visit variability of HbA1c and increased risk of dementia in patients with diabetes. Moreover, meta-analyses for the above association were separately performed according to the different parameters for HbA1c variability (HbA1c-CV and HbA1c-SD) and different analytic methods (continuous and categorized variables). Finally, for all of the included studies, the association between HbA1c variability and incidence of dementia was obtained in multivariate analyses after adjustment of possible confounding factors. Accordingly, a potential independent relationship between increased HbA1c variability and higher incidence of dementia in patients with diabetes could be retrieved. Taken together, these findings suggested that increased long-term glycemic fluctuation as evidenced by increased visit-to-visit variability of HbA1c may be an independent risk factor dementia in patients with diabetes. The results of the meta-analysis are consistent with findings of some previous studies which evaluated the association between glycemic variability and changes in cognitive function. An early study showed that higher acute glycemic peak indicated by the decreased level of 1,5-anhydroglucitol  was independently associated with cognitive decline and dementia in community-based population of the Atherosclerosis Risk in Communities study . In addiOur study has limitations. First, studies available for the meta-analysis were retrospective, which may be confounded by the recall or selection biases. Therefore, prospective cohort studies are needed for validation. Second, limited datasets were available for each metrics of HbA1c variability, and we were unable to evaluate the influences of study patient or study characteristics on the association, such as the age, sex, comorbidities, and follow-up durations. Large-scale prospective studies are also warranted for further investigation. Besides, we did not search for grey literatures or make contact with the related researchers for possibly unpublished data, which may also lead to additional bias of the systematic review. In addition, almost all studies included T2DM patients. Accordingly, the possible association between HbA1c variability and risk of dementia in T1DM patients should be evaluated in future studies. Moreover, although studies with multivariate analysis were included, we could not exclude the existence of residual factors that may affect the association, such as the concurrent use of antidiabetic medications that may reduce glycemic fluctuation. Furthermore, we could not determine the possible influence of publication bias on the results since only five studies were included because tests for funnel plot asymmetry and Egger's regression analysis could not be performed. Finally, a causative relationship between HbA1c variability and dementia could not be derived based on our study because it is a meta-analysis of observational studies. Clinical trials may be considered to evaluate whether reduction of glycemic fluctuation could reduce the incidence of dementia in diabetic patients.In conclusion, results of the meta-analysis showed that increased HbA1c variability in patients with diabetes was significantly associated with higher risk of dementia. Glycemic fluctuation should be considered as a risk factor for dementia in diabetic patients, which should be considered in the determination of optimal hypoglycemic regimens in these patients.


Recurrent pregnancy loss (RPL) is a complex disorder affecting thousands of women around the world. The etiopathogenesis of RPL is not yet fully known and is considered to be multifactorial. Among the various causes, scientific research has identified the key role of thrombophilia. In this scenario, the H1299R variant in FV also seems to be involved; however, the relative data is often discordant. This study provides empirical evidence disproving the correlation between the FV H1299R variant and RPL, thus constituting a valid support for medical care during pregnancy and genetic counseling, in particular for gynecologists, obstetricians, and genetic counselors.p = 0.44). Subgroup analyses considering H1299R in heterozygosity  and in homozygosity  revealed a similar trend. Lastly, we evaluated the association between H1299R and RPL based on the number of previous miscarriages (≥2 or ≥3). This comprehensive systematic review and meta-analysis sheds light on the specific influence of the H1299R variant in the F5 gene on RPL, constituting valid support for medical care during pregnancy and genetic counseling.This study evaluated the association between the H1299R factor V (FV) variant (rs1800595) and recurrent pregnancy loss (RPL). Pubmed (MEDLINE) and Embase (OVID) bibliographic databases were searched from the inception to 31 May 2022 to identify suitable articles according to PRISMA and MOOSE guidelines. We included observational studies, case-control studies, cross-sectional studies, and cohort studies reporting a numerical and well-distinguished Het or Hom status of the H1299R variant obtained through PCR or other biochemical techniques and comparing RPL patients with a healthy control group. The review protocol was registered at PROSPERO (CRD42022330077). Two authors independently screened studies, extracted data, and carried out the risk of bias assessment using the Newcastle Ottawa scale (NOS). A meta-analysis was performed with RevMan software Version 5.4 using an odds ratio (OR) with an M-H, random effect, and 95% CI. We included 13 clinical studies for a total of 1669 RPL patients and 1466 healthy women as a control group. H1299R variant was slightly associated with RPL albeit without significance (OR 1.18, 95% CI: 0.78–1.80,  Recurrent pregnancy loss (RPL) constitutes about 1% of all cases of pregnancy loss (PL) [Considering the emotional impact of this experience, both men and women affected by RPL show high risks of developing depression and anxiety, and they very often need psychological support to overcome the traumatic event .Moreover, women with a history of PL showed an increased risk for subsequent loss .There are different classifications of RPL; in fact, according to the European Society of Human Reproduction and Embryology (ESHRE) and the American Society for Reproductive Medicine (ASRM) guidelines, it is defined as the loss of 2 or more pregnancies before 24 weeks of pregnancy . ConversAlthough multiple risk factors for RPL have been identified, the pathogenesis of RPL remains undetermined in more than 50% of cases [It is important to pay attention to medical conditions present in the family or recurring in the reproductive history of the couples, recommending, in particular, to base the prognosis on the number of previous abortions and the female age . As a muThrombophilia is a blood coagulation condition predisposing a hypercoagulability status. Thrombophilia can be inherited or acquired, and it is commonly associated with an increased risk of venous thromboembolism (VTE) . HereditIn a small group of patients, antithrombotic prophylaxis during pregnancy could reduce complications and increase the live birth rate ,8.F5 gene (Coagulation Factor V) are among the most common causes of inherited thrombophilia.Mutations in the In particular, the well-known Leiden mutation G1691A  causes APC resistance which is associated with an increased risk of VTE and pregnancy complications, such as RPL ,9.F5 gene A4070G, p.(His1299Arg), known as R2 or H1299R (rs1800595), was identified and linked to hereditary thrombophilia. Previous studies have shown that His1299Arg change will increase the VTE risk 2–3 fold [In 1996, another missense variant in exon 13 of the FV H1299R is associated with mild APC resistance and with a relative excess of the more thrombogenic isoform FV in plasma . Recent findings indicate the H1299R variant in Factor V (FV) as an important influencing factor in the risk of fetal loss, intrauterine growth restriction (IUGR) and stillbirth, early miscarriage, and pre-eclampsia ,11. Nevertheless, conflicting data seems to disprove these assumptions, excluding the key role of H1299R in the etiopathogenesis of RPL [Therefore, based on this unresolved question, this study aimed to perform an exhaustive meta-analysis in order to better understand the association between the FV variant H1299R and the risk of RPL.The protocol of this study has been recorded in the PROSPERO register (CRD42022330077) and has already been published . SystemaAPC and AA performed a bibliographic search using MEDLINE (PubMed) and EMBASE (Ovid) databases according to the eligibility criteria summarized in Two content experts (SB and EE) designed a search strategy and supervised the study.After removing duplicates from the two different databases, two review authors (APC and AA) individually screened the titles and abstracts of all records identified to remove articles that were not relevant. Next, we examined the full-text articles to select the records that corresponded most closely to the eligibility criteria; conflicting opinions were resolved through the mediation of a third review author (SB).The individual extraction of the data from the included articles was executed by two authors (APC and AA). We collected the following data: author(s), year of publication, study catchment area , study population , study period, study design, the H1299R variant, and Het or Hom genotype as well as the number of previous miscarriages and mean age of women. Events or non-events were expressed as the number of patients with the H1299R variant (Het and/or Hom) in RPL or healthy females, respectively.The quality of the included studies reported in this meta-analysis was independently assessed by two reviewers  using the Newcastle Ottawa scale NOS; see .Then, the study’s quality was classified as low, medium, or high on the basis of the NOS score. Disagreements in score assignments were resolved through discussion or the intervention of a third review author (SB).For statistical analysis, we used an odds ratio (OR) measure and the random-effects model with the Mantel-Haenszel method. At the end, we obtained pooled estimates of the variant effect (OR) with the associated 95% confidence interval (CI).2 statistic as previously described [The heterogeneity was originally evaluated through a graphical examination of the forest plots and then assessed using the Iescribed . SubgrouReview Manager  was used to perform the meta-analysis of the obtained data.In the first step, we identified 7391 records using the two databases PubMed (MEDLINE) and Embase (OVID). For this purpose, Medical Subject Headings (MeSH) referring to the thrombophilic variant H1299R and RPL were used as previously illustrated in the study protocol [After removing duplicates, we retrieved 3382 records to be screened for inclusion. We excluded 3347 articles after reading the title and abstract because they were not relevant to our review question.Then, we examined the full-text of 35 articles for eligibility, excluding 22 records as they did not match the established inclusion and exclusion criteria.Finally, we included 13 studies in our systematic review and meta-analysis, as shown by the PRISMA Flowchart reported in We included 13 clinical studies for a total of 3135 women, of which 1669 RPL and 1466 healthy subjects. The main characteristics of the included studies are summarized in After analysis of the data extracted from every single study, we carried out preliminary evaluations. Relatedly, of the 13 records included, 8 investigated the influence of H1299R in the Asian population 61.54%, A for a tThe NOS scores are shown in After the authors’ evaluations, only three articles were considered to be at moderate risk of bias as they lacked specific data on the mean ± SD age of the individuals. For this reason, to further assess the validity of our study, we performed a sensitivity analysis excluding the studies with a low NOS score. Therefore, we excluded the studies of Arabkhazaeli et al., Dilley et al., and Torabi et al. in order to ensure they did not compromise the results of the entire survey and lead to misleading conclusions in our meta-analysis.All the other articles were considered low risk, scoring well on the NOS scale.First, we evaluated the correlation between the H1299R variant and RPL not considering the heterozygous or homozygous status .2 = 62%), the total OR was 1.18 .The 13 articles included showed an ORs range between 0.33–3.91. Despite the considerable degree of heterogeneity between studies .In the analysis referring to the H1299R variant in heterozygosity, the 13 eligible revealed a range of ORs between 0.37–3.31 . In thisp = 0.56).Thus, the statistical analysis of the H1299R variant in heterozygosity revealed an increase of 13% in RPL compared to the healthy female group. However, despite the fact that the trend was also comparable to the precedent in this case, the result was not significant . Indeed, with an OR of 2.11, the presence of GG status for the A4070G variant increased in RPL individuals by 111% compared to the successful pregnancy group. The degree of statistical heterogeneity was I2 = 0%.The ORs of the estimated studies ranged from 0.20 to 5.13. The analysis of pooled data from the 13 studies indicated a noticeable association between the H1299R variant in homozygosity and RPL , albeit not significantly . These outcomes are comparable to those shown in the plot of p = 0.44), in which all eligible studies were included. This proved that the inclusion of the three high-risk bias studies  did not compromise the results of our meta-analysis.Moreover, as shown in At present, RPL is a heterogeneous condition caused by environmental and genetic factors. The etiology of RPL cases remains undefined, and a limit to estimating the risk of recurrence persists in clinical practice .Hormonal and physical changes in pregnancy increase the possible formation of clots in the placental blood vessels, thus leading to RPL ,26. To avoid clinical complications, drug treatment may be prescribed according to the individual clinical history; usually, this is based on the administration of acetylsalicylic acid as an antiaggregant and/or heparin as an anticoagulant . In factIn the last few decades, the attention of researchers has been directed to Factor V, a blood-clotting protein, also known as proaccelerin or labile factor . Unlike In addition to the FV Leiden mutation, another variant, commonly referred to as H1299R, affects the plasma concentration of FV and causes a mild resistance to activated protein C .F5 gene, results in the change of codon 1299 Histidine into a different amino acid Arginine and has also been described as polymorphism R2 [This missense variant, the substitution of a nucleotide residue A 4070 in G in the phism R2 . The H12phism R2 . The prephism R2 ; on the p = 0.44).Our meta-analysis included 13 studies with a total of 3135 subjects: 1466 healthy women as a control group and 1669 RPL patients. Compared to the reference group, our evidence suggested that the H1299R variant was not significantly associated with RPL, although the trend showed a slight increase in the RPL-related incidence of the H1299R. More precisely, in our first assessment without distinction between Het or Hom status, pooled data indicated an increase of 18% in the H1299R variant for the RPL subjects . Likewise, the H1299R variant in homozygosity was related to the RPL group to a greater extent than the healthy group by 111%, although not in a significant way . This pooled data is influenced by the studies by Dissanayake et al., Izuhara et al., and Sotiriadis et al., in which the presence of GG subjects was equal in both groups or superior in the control group. Moreover, the lower frequency of homozygous variants compared to heterozygotes should be considered, which results in limited evidence for RPL H1299R homozygous women with no clear outcome.Since the rarity of homozygotes and the more frequent heterozygous condition have a greater public health impact , we estip = 0.67) or RCOG . Alternatively, when a subgroup analysis was carried out considering the different criteria for defining RPL in current guidelines, a comparable trend emerges for both the ESHRE and ASRM definition .The relation between the H1299R variant and RPL, as reported, was also negligible in the sensitivity analysis  and the high degree of heterogeneity between the studies, the result should be interpreted with caution. The statistics of genotypes and allelic frequencies, excluding the weight of the individual studies as well as the degree of heterogeneity, indicate a similar trend but with a considerable significance see . Other limitations of this meta-analysis must be addressed. Some important factors could play a role, such as age, co-morbidities status, smoking habit, previous at-term pregnancy, body mass index (BMI), or other genetic variants involved. In addition, we cannot exclude a lower prevalence of chromosomal abnormalities, autoimmune and thyroid disorders, or other conditions not diagnosed or not reported in the study groups but are associated with an increased risk of RPL.Unfortunately, karyotype analysis was not present in all the selected articles, and this is well-known contributing information to the individual risk assessment of RPL women. However, what remains crucial is that genetic counseling and information on care and treatment options should be offered to RPL couples .No systematic reviews and meta-analyses have specifically addressed the role of H1299R in the context of recurrent miscarriage. The most recent scientific evidence, given by Liu et al. , reportsThis meta-analysis demonstrated that there is no clear association between the FV H1299R variant and RPL. The present study lays a basis for future research in the H1299R variant and RPL, constituting valid support for medical care during pregnancy and genetic counseling.However, the limitations of this meta-analysis must be addressed. First, the sample size was relatively small and might not have provided sufficient power to estimate the associations. Hence, large studies on RPL couples would provide significant new insights into the clinical relevance of genetic tests and other specific marker evaluations and should also consider the male contribution more deeply.


Risk of ovarian cancer in women with frequent perineal talcum powder product is not well understood. Prior systematic reviews focused on ever use. The purpose of this study is to estimate the association between frequent (at least 2 times per week) perineal talcum powder use and ovarian cancer.I2 statistic. Funnel plot and Eger’s test were performed to assess publication bias. Subgroup and sensitivity analyses were performed for testing the robustness of the overall findings.A systematic review and meta-analysis was conducted according to meta-analysis of observational studies in epidemiology guidelines. Study protocol was prospectively registered at PROSPERO (registration number CRD42020172720). Searches were performed in PubMed, Embase, Web of Science, and Cochrane Central Register of Controlled Trials databases from their inception to August 2, 2021. Case-control and cohort studies were included if they reported frequent perineal talcum powder use and an adjusted odds ratio or hazard ratio for ovarian cancer. Review for inclusion, data extraction, and quality assessment  were performed independently by two reviewers. Pooled adjusted odds ratios with 95% confidence intervals were generated from the random effects model. Heterogeneity was quantified with κ = 0.88). Publication quality was high . Frequent talcum powder use was associated with an elevated risk of ovarian cancer . There was no evidence of bias and low heterogeneity . There was no meaningful difference limiting analysis to publications with a NOS quality score of 8 or 9 or limiting studies based on study design.Initial database searches returned 761 unique citations and after review, eleven studies describing 66,876 patients, and 6542 cancers were included (Cohen’s This review suggests an increased risk of ovarian cancer associated with frequent perineal powder exposure of 31–65%.The online version contains supplementary material available at 10.1007/s11606-022-07414-7. All studies including retrospective case-control studies have found a positive association.7 The most recent review by O’Brien1 limited analysis to the four prospective cohort studies and in its main conclusion stated there was no statistically significant association between genital talc use and ovarian cancer.Talc, the primary ingredient in baby powder, is a naturally occurring mineral known for its softness and absorbency and has been added to a broad range of personal care products since the early part of the twentieth century. To date, there have been seven systematic reviews and pooled data studiesThe differences in conclusions between the metanalyses are at least partially due to the inconsistent talcum-based powder exposure questions regarding the frequency and type of exposure. To harmonize the exposure measurements across the greatest number of studies, prior meta-analyses primarily focused on quantifying the association between ever versus never use of talcum powder products and ovarian cancer. However, ever use is a non-specific exposure that could dilute or obscure a meaningful association as ever use would combine women with low and high exposures to talcum powder.Knowledge of ovarian cancer risks are important for women’s health and important to guide regulatory oversight. The purpose of this analysis is to estimate the risk of ovarian cancer associated with the frequent use of talcum powder products. We hypothesize that assessment of ovarian cancer risk among frequent users of talcum powder products would provide a more meaningful assessment of its carcinogenicity.We conducted a systematic review of the literature and meta-analysis to assess the association between the frequent perineal exposure to talc and ovarian cancer following the Meta-analyses of Observational studies (MOOSE) reporting guidelines. A study protocol was developed in advance and registered with the International Prospective Register of Systematic Reviews (PROSPERO) on April 28, 2020 (registration number: CRD42020172720).Comprehensive searches were performed by an expert health science informationist from inception of the relevant databases to August 2, 2021. Searches were completed in the following: PubMed, Embase, Web of Science, and Cochrane Central Register of Controlled Trials. Each search consisted of talcum powder and ovarian cancer concept blocks, which can be viewed in the supplemental material. No date, language, or other restrictions were incorporated into the searches. Duplicate citations were removed in Endnote X9.3.1 . The references of all publications were searched to identify additional publications.Selection of studies included observational cohort and case-control study designs. Studies were included if they reported primary data on frequent, defined as multiple (2 or more) times per week perineal exposure to talc, and reported an adjusted odds ratio or hazard ratio and 95% confidence interval (CI) for ovarian malignancy. Other uses of talcum powder, including applications to the body, were excluded to isolate exposure mechanism to perineal application. Conference abstracts, retracted manuscripts, narrative reviews, editorials, case reports, and manuscripts not reporting the location or frequency of talcum powder application were excluded.n>10 cancers), and defined research methods to allow assessment of inclusion and exclusion criteria  were independently reviewed by two authors (SW and RSB). Agreement for inclusion was calculated using the Cohen k with the following scale: 0.01 to 0.20 indicates slight; 0.21 to 0.40, fair; 0.41 to 0.60, moderate; 0.61 to 0.8, substantial; and 0.81 to 0.99, almost perfect. Disagreements were resolved by discussions.Studies were screened for inclusion using prespecified selection criteria by a single author (SW). Selection criteria included publication of primary data, reporting on multiple times per week (≥ 2 times per week) perineal exposure to talcum powder including direct application of talcum powder to the perineum and rectum, application to underwear or sanitary napkins, or on birth control devices like diaphragms and risk for ovarian malignancy. Studies were also selected for baseline quality requiring a multivariable risk adjustment, study size n>0 cancers1 did not meet the pre-specified definition for frequent exposure. However, the questionnaires for two of the included cohorts had asked women about more frequent talcum powder use. As is standard in systematic reviews to include relevant but unpublished results, we contacted O’Brien and requested primary data from the Nurses’ Health Study 1 (NHS1) and the Sisters Study (SIS) for the highest frequency talc exposure group. The data from NHS 1 were provided and described in the Supplemental Table n=2 women).The four prospective cohort studies as reported in O’BrienData extraction was performed by two authors (SW and RSB). Extracted information included age range, enrollment period, definition of frequency of talc use, size of control group or cohort size, number of ovarian cancers, and adjusted hazard ratio and odds ratio with 95% CI. Data were included from the highest reported talc use category to obtain as close to daily use as possible and the referent group were women who reported no talc exposure. When duplicate reports of the same subjects were published, the publication reporting the highest talc use was selected. The senior author was contacted to obtain data for studies that reported frequent perineal talcum powder exposure but did not publish the results on this exposure. Disagreements in data extraction were resolved by consensus.Eleven articles met selection criteria. The articles were independently reviewed by two authors (SW and RSB) for quality using the Newcastle Ottawa Scale (NOS) where a score of 0–3 reflects a very high risk of bias, 4–6 reflects a high risk of bias, and 7–9 reflects a high-quality study with low risk of bias. The scale assesses the criteria used to select study groups, the comparability of study groups, and ascertainment exposure or outcome of interest. Results of the validity assessment were discussed until agreement was reached Table .Table 18 and displayed with forest plots. Adjusted odds ratios and the adjusted hazard ratio were combined given the infrequency of ovarian cancer.9 As a sensitivity analysis, we removed the one cohort study from the analysis and a study that combined non-perineal talcum powder users with perineal talcum powder users.Individual study results were combined using summary estimates generated from the random effects modelI2 values. Publication bias was evaluated by visual inspection of the funnel plot and statistically with Egger’s test. The NOS score was calculated for each study and median, maximum, and minimum scores were calculated across all included studies. As sensitivity analyses, we repeated the meta-analysis first excluding the study with the NOS score of 4, and then repeated the analysis limited to studies with an NOS score of 8 or 9. SAS v. 9.4 was used, and two-sidedP-values less than 0.05 were considered statistically significant.Heterogeneity was evaluated by inspecting funnel plots, and by calculating the 19 The interrater agreement in determining the final study cohort from the 52 full-text reviews was excellent (Cohen’s k=0.88). The included studies include 10 retrospective case-control studies and a single cohort study. The median NOS of included case-control studies was 8 (range: 4 to 8). The NOS of the included cohort study was 9.Initial database searches returned 761 unique citations Fig. .1,10–19 P=0.22) of the variation across studies were due to heterogeneity. The summary pooled odds ratio assessing the association between frequent use of perineal talcum powder products and ovarian cancer was 1.47     without publication bias   reported daily exposure. The studies were homogeneous, and 24.4% (10). There was no meaningful change after excluding Booth, summary pooled odds ratio 1.48   without publication bias  , Cook et al.12 (NOS=7), and Whittemore et al.18 (NOS=7), also without a statistically significant change in the summary pooled odds ratio of 1.48   and did not have publication bias  . The 11 contributing studies included in the review, including the longest published follow-up available from the Nurses’ Health Study cohort, were homogenous, and the summary estimate was robust in the sensitivity analysis. This meta-analysis makes a significant contribution to the available evidence as it is the first study that summarizes the published cohort and case-control literature that focuses on frequent (multiple times per week) rather than ever use of talc.21 Talc fibers are found within normal ovaries and within ovarian cancer with “cosmetic” talc use23 supporting this theory. A case series by Steffen et al. reported 10 cases of patients with “cosmetic” talc exposure and serous ovarian cancer evaluated the surgical specimens as well as cosmetic talcum powder manufactured in the 1950s. The transmission electron microscope tissue analysis and phase contrast microscopy found talc in every serous ovarian cancer and anthophyllite asbestos in 80% (8/10) of the serous ovarian cancers, which matched the talcum-based powder from the 1950s. Asbestiform talc is considered, along with asbestos, as a class 1 carcinogen for ovarian cancer, by the International Agency for Research on Cancer.24 Thus, the strongest and most widely believed theory is that asbestiform talc fibers and asbestos fibers are the etiological agents leading to the elevated cancer risk associated with their use.The precise mechanism whereby talcum powder causes ovarian cancer is not fully understood. It is widely speculated that trans-genital migration of talc powder through the fallopian tubes to the ovaries and peritoneum results in inflammation and a cascade of changes that result in carcinogenesis.7 O’Brien et al.1 concluded that perineal talcum powder exposure in cohort studies was not significantly associated with ovarian cancer. However, when O’Brien limited to women with patent fallopian tubes the hazard was 1.13 (95% CI: 1.01 to 1.26) for ever versus never use and there was a dose response with increasing risk with increasing frequency of talcum powder use with a hazard ratio of 1.40 (95% CI: 1.17 to 1.68) for daily users. The magnitude of the higher association in our study compared to prior case-control and cohort meta-analyses was likely due to our focus on frequent rather than any talcum powder users, inclusion of quality studies, and consistent definition of the exposure.The pooled odds ratio of 1.47 is higher than that of six additional systematic reviews which included case-control studies, all of which also report a statistically significant association between talc and ovarian cancer (range of adjusted odds ratios: 1.24–1.35).27 Although it is well known that case-control study design is susceptible to recall bias and misclassification, the bias was likely limited to participant recollection of their exposure rather than influenced by the media, given there was no publicity on the topic at the time of most publications: the first legal case was reported in the press in 2014 long after most studies completed recruitment. The one study where patient recruitment occurred after 2014 patients was Schildkraut et al.,17 where recruitment occurred between 2010 and 1015, and they adjusted for the additional bias.Our meta-analysis included both case-control and cohort observational studies allowing use to include more cancer cases than cohort alone. Although there is the general belief that cohort studies are better than case-control studies, both can provide accurate and meaningful information about statistical associations. Since most publications on talc used a case-control design with detailed quantification of the type and frequency of talc exposure missing from most of the cohort studies, it is important to include the data from the case-control studies in any summary estimate of the association with ovarian cancer. While cohort studies can provide a superior design for some research questions, the method provides less useful results when quantification of the exposure is too crude to provide a meaningful estimation of exposure. Cohort studies for talcum powder did not define the type of powder exposure, consistently define frequency and duration, capture changes in exposure over time, and relied on recall by participants for exposure which may involve misclassification as would be expected in case control studies.13 and this is the first systematic review to focus on multiple times per week users. The results were highly consistent and homogenous, and the included studies were of high quality. The work has limitations as well. We constructed our selection criteria prospectively to include studies with multiple times per week and as close to daily talcum powder exposure as possible. However, this meant that cohort and case-control studies that might have frequent-use patients were excluded if the questionnaire did not explicitly capture this information. The definition of talcum powder use varied by frequency and duration between the case-control and cohort studies. Additionally, studies by Cook et al.12, Mills et al.15, Rosenblatt et al.16, and Schildkraut et al.17 were unable to differentiate between use of perineal powders and the small subset using cornstarch (estimated at 1.5%). However, the differences in definition and small inclusion of cornstarch likely did not affect the results as there was no evidence for statistical heterogeneity in our study. The included studies were adjusted for multiple covariates. The possibility of additional confounders to the studies likely exists.The primary strength of our study is our focus on frequent users of perineal talcum powder. Among women who report talcum powder use, the most common frequency is daily use,In this analysis of pooled data from 10 case-control studies and a single cohort study, the frequent use of perineal talcum powder use is associated with increased risk of ovarian cancer. These results support women avoiding the frequent use of talcum powder in the perineal area.ESM 1(DOCX 13883 kb)