Missing heritability is a common problem in psychiatry that impedes precision medicine approaches to autism and other heritable complex disorders. This proof-of-concept study uses a systematic review and meta-analysis of the association between variants of the serotonin transporter promoter (5-HTTLPR) and autism to explore the hypothesis that some missing heritability can be explained using an optimum curve. A systematic literature search was performed to identify transmission disequilibrium tests on the short/long (S/L) 5-HTTLPR polymorphism in relation to autism. We analysed five American, seven European, four Asian and two American/European samples. We found no transmission preference in the joint samples and in Europe, preferential transmission of S in America and preferential transmission of L in Asia. Heritability will be underestimated or missed in genetic association studies if two alternative genetic variants are associated with the same disorder in different subsets of a sample. An optimum curve, relating a multifactorial biological variable that incorporates genes and environment to a score for a human trait, such as social competence, can explain this. We suggest that variants of functionally related genes will sometimes appear in fixed combinations at both sides of an optimum curve and propose that future association studies should account for such combinations. In this paper, we challenge the well-established finding that there is no association between the short/long 5-HTTLPR polymorphism and autism spectrum disorder (ASD). We show that the short 5-HTTLPR variant is associated with ASD in a well-described, homogeneous subgroup of cases, while the long 5-HTTLPR variant is associated with the same disorder in an alternative homogeneous subgroup and argue that both subgroups may represent the two extreme, biologically opposite ends of an optimum curve. For clinical practice, our findings imply that serotonergic drugs may relieve symptoms of ASD in individuals whose genetic and environmental make-up is represented by one end of an optimum curve, while potentially aggravating the same disorder at the opposite end of the curve. In pharmaceutical research of these medications, beneficial effects may be masked by adverse effects in a mixed ASD population or vice versa, which may cause both under- and overmedication of individuals with ASD. Recent evidence suggests that indeed, a correlation exists between an individual’s 5-HTTLPR variants (short and/or long) and the selective serotonin reuptake inhibitor (SSRI) response in ASD . The conUnlike somatic diseases, neuropsychiatric disorders are diagnosed on the basis of symptoms alone, and as such, may have multiple aetiologies. A common example is ASD, a neurodevelopmental disorder that is defined by a combination of two core symptom domains: persistent deficits in social communication and social interaction across multiple contexts, and restricted, repetitive patterns of behaviour, interests or activities . Twin anSLC6A4 gene on chromosome 17. The promoter region of this gene, the 5-HTT gene-linked polymorphic region (5-HTTLPR), is characterized by an insertion/deletion polymorphism, resulting in the occurrence of a number of alternative allelic variants. Traditionally, two common variants are distinguished, indicated as the short (484 bp) and the long (528 bp) variant [One of the earliest and most consistent findings in biological ASD research is the occurrence of elevated levels of whole blood serotonin  in individuals with ASD and in their first-degree relatives . This is variant . Functio variant ,14. p = 0.002) but not in European and Asian samples. Homogeneity testing in their sample indicated heterogeneity within the set of joint samples, whereas the American and Asian sets were homogeneous. Recent evidence suggests that at the physiological level, ASD can be associated either with enhancement or with depletion of serotonin transporter function and extracellular serotonin availability [The authors of one meta-analysis  report olability . CombineIn recent literature, dose-response curves between biological variables and psychological traits have often been shown to adopt an inverted U-shape, where the biological ‘dose’ on the horizontal axis will be multifactorial in most cases. The inverted U-shape of these psychological dose–response curves is reminiscent of the well-known physiological optimum curves for enzyme activity as a function of acidity and may reflect a similar mechanism: too high a dose can have the same effect as a deficit. As a matter of course, optima do, in fact, apply to virtually every physiological parameter, ranging from body temperature and blood pressure to the local activities of intra- and extracellular physiological substances. If we plot a measure for general health against each one of these parameters, the resulting graphs will almost always take an inverted U shape . It is therefore not so far-fetched to presume that the genetic variants that underlie physiological parameters will also relate to optimum curves.SLC6A4 and ASD. Subsequently, we evaluated the results of this meta-analysis in the context of our hypothesis.Crucially, we here hypothesize that the mathematical function that relates an explanatory multifactorial variable  to the dependent score for social competence is an optimum curve and that ASD is expressed as an insufficient score at the two opposite ends of this curve, where specific combinations of genetic variants and environmental factors that contribute to a multifactorial variable are overrepresented . As a prOur first research question is whether both the short and the long 5-HTTLPR variant are associated with ASD in two different subgroups of the world-wide ASD population, i.e., in subgroups that differ in continental origin. Our second, more fundamental research question is whether the association between 5-HTTLPR and ASD represents an example of missing heritability that can be explained using an optimum curve. With this proof-of-concept study, we hope to offer a mechanistic approach for addressing missing heritability in ASD and, more broadly, in the pathology of complex disorders.Our literature search resulted in a set of 17 publications reporting on 18 studies that met our selection criteria ,30,31,32p-values on the null-hypothesis of odds ratio (OR) = 1.We performed a meta-analysis on the preferential transmission of the short or the long 5-HTTLPR variant from heterozygous parents to offspring with ASD for the full set of 18 TDT studies. Subsequently, we performed separate meta-analyses for three continentally differentiated subsets of studies on samples originating from, respectively, America (five studies), Europe (seven studies) and Asia (four studies). p = 0.079). The individual continental meta-analyses yielded a more detailed image: a clear and significant preference for transmission of the short variant to subjects in the American samples , no preferential transmission in the European samples , and a clear and significant preference for transmission of the long variant to subjects in the Asian samples . The odds ratios and their 95% confidence intervals, both sorted and pooled by continent, are presented in a forest plot in In accordance with the results of previous meta-analyses ,14, we fp = 0.34) (see p = 0.95).A funnel plot  suggeste.34) see . The resp = 0.053).A sensitivity analysis, based on a stepwise omission of one study at a time, showed the following: within the respective groups of European and American studies, the overall result  was not affected by leaving out any of the studies, whereas within the group of Asian studies, the exclusion of the study by Cho et al. (2007)  changed In this study, we used the concept of an optimum curve to address missing heritability. Furthermore, we used conflicting results and statistical heterogeneity as a proof of concept to reconstruct a concrete biological mechanism.Our finding that there was no preferential transmission of either the short or the long 5-HTTLPR variant from heterozygous parents to their offspring with ASD at the global scale is in accordance with the results of earlier meta-analyses. In contrast to this overall finding, we found preferential transmission of the short variant to offspring with ASD in America and preferential transmission of the long variant in Asia. These findings support our hypothesis that genetic associations may act through an optimum curve, where the impairment of a trait  may result from a multifactorial variable that is either too low or too high. If an optimum curve applies, each variant of a gene may act either as a risk factor or as a protective factor for ASD, depending on the genetic and environmental context in which it occurs. Our physiological interpretation of this phenomenon—that serotonin metabolism can be biased in two opposite ways, each of which may lead to ASD—is in accordance with recent findings .For reasons of simplification, we have restricted ASD to one of its two core symptoms, i.e., ‘deficits in social interaction’, thereby neglecting the other core symptom, i.e., ‘repetitive behaviour or restricted interests’. This begs the question if and how an optimum curve may relate a multifactorial score to a combination of symptoms, rather than to a single symptom only. The answer is that we would need two optimum curves with a common horizontal axis but with different vertical axes: one for the score for social competence, and one for the score for a second psychological trait, i.e., the healthy counterpart of repetitive behaviour or restricted interests.This study is of both clinical and conceptual relevance. The clinical relevance lies in our finding that both the short and the long 5-HTTLPR variants can be associated with autism and that the association is context-dependent. We believe that this finding may help open up the way towards precision medicine for ASD, especially with regard to serotonergic drugs, such as selective serotonin reuptake inhibitors (SSRIs). Although SSRIs are primarily indicated for treating major depression, they have also been prescribed for the treatment of ASD symptoms . SSRIs hThe conceptual relevance of our study lies in the introduction of a new approach to missing heritability, which, as we show, works for at least one case. More broadly, it illustrates the use of mechanistic thinking in addressing missing heritability and the value of unravelling mechanisms to address this problem. G and LA [The main strength of this study is its mechanistic approach. Although many authors consider population stratification to be a likely source of conflicting results in genetic association studies and a cause of statistical heterogeneity, the phenomenon has not been used to reconstruct a biological mechanism before. However, some limitations must also be acknowledged. First, continental origin is not a biological measure, and its association with a disorder can only be indirect. It may relate to genetic aspects of ethnicity, to cultural environmental aspects such as diet or lifestyle, or to a combination of genetic and environmental aspects. Second, the number of studies included in this meta-analysis is relatively small in light of the ambitious goal of our study. As our sensitivity analysis indicated, this was especially the case for the studies on samples from Asia. Further research is therefore needed to confirm or disprove the genetic associations from our analysis. Third, in the association studies analysed here, the finding that the short/long 5-HTTLPR polymorphism is triallelic rather than biallelic, with two alternative common long variants, LG and LA , was notThe results of this study underline that future genetic association studies should focus more often on combinations of genetic variants or on combinations of genetic variants and environmental factors , rather than on single variants. Groups of functionally related genes  could serve as a starting point for choosing meaningful combinations to assess for possible association with a disorder. Continental origin is not a factor that is known to be related directly to serotonin availability. The reason that we chose this factor, rather than a second serotonergic gene, was the fact that the information on it was readily available, combined with the fact that it seemed to correlate with the association between 5-HTTLPR and ASD. Virtually every publication on a genetic association study mentions the continental origin of the assessed samples. Although this information enabled us to perform our proof-of-concept study, we expect combinations of variants of different serotonergic genes to be even more convincingly related to ASD. If it is true that both extreme enhancement and depletion of serotonin availability are associated with ASD , it woulWe performed an electronic literature search of the PubMed database at the U.S. National Library of Medicine and of Elsevier’s Embase biomedical and pharmacological database, from inception up to February 2019, using the following combinations of text words as search criteria: autism AND serotonin AND transporter; autism AND SLC6A4; autism AND 5-HTTLPR; autism AND 5HTTLPR. We also manually searched the reference lists of review articles and meta-analyses.Studies were included in our selection if: 1. They were TDT studies on the genetic association between the short/long 5-HTTLPR polymorphism and ASD; 2. The reported data allowed for the calculation of the odds ratio of transmission; 3. Samples did not overlap between studies; 4. The studies were in English. From each study, the following data were extracted independently by the first and the second author: 1. Year of publication; 2. Continental origin(s) of the sample; 3. Sample characteristics; 4. Number of short and long 5-HTTLPR variants, transmitted and not transmitted, respectively, from heterozygous parents to offspring with ASD. Discrepancies were resolved by mutual consent. In cases where published data were unclear, we contacted the authors for clarification.p-value corresponding to the null hypothesis OR = 1 was determined through a χ2 test. McNemar’s test [2 and p-value calculations. For every individual study, we calculated the odds ratio. For each odds ratio, the 95% confidence interval was calculated, and the r’s test  was usedp-value were synthesized for all studies combined. We based our meta-analysis on a fixed-effect model rather than on a random-effects model, because our aim was to explicitly investigate the hypothesis of non-random across-study heterogeneity , rather than purely statistical heterogeneity [A pooled odds ratio and its 95% confidence interval and ogeneity .Q [I2 statistic [p-values for the subgroups of studies that comprised only American, European or Asian samples. To account for potential publication bias, we used Begg’s funnel plot [Heterogeneity among studies was assessed using Cochran’s Q  and the tatistic . To invenel plot , supplemnel plot . AdditioA pre-specified sensitivity analysis to evaluate which studies had substantial impact on between-study heterogeneity was performed by leaving out studies one by one, both for the overall group of studies and for each of the continental subgroups of studies separately.For the statistical analysis, we chose to design our own spreadsheet in Excel 2016 (Microsoft) rather than using an existing software package, in order to provide optimal transparency of the mathematical formulas and calculations used. The central measure of this study was the odds ratio, calculated as the odd of transmission of the short relative to that of the long 5-HTTLPR variant, transmitted from heterozygous parents to offspring with ASD. The main outcome measure was preferential transmission, or no preference, for the total set of samples and for subsets of American, European and Asian samples.In this proof-of concept study, we used a meta-analysis on 5-HTTLPR and ASD to show how demonstrable genetic associations may be underestimated or missed in conventional genetic association studies. Despite a lack of association between the 5-HTTLPR variant and ASD in a combined set of 18 TDT studies, we found the short variant to be associated with ASD in the subset of American samples and the long variant to be associated with ASD in the subset of samples from Asia. In the joint set, the variants mutually masked each other’s association with ASD. This phenomenon can be explained using an optimum curve, relating a multifactorial biological variable on the horizontal axis, defined by genes and environment, to a score for social competence on the vertical axis. The results support our hypothesis that in a mixed population, two alternative genetic variants of the same gene may both be associated with the same disorder, albeit in different genetic and environmental contexts. This concept may apply to any inverted U-shaped relationship between a multifactorial variable and a physical or psychological trait. If our proof of concept holds up, it has the potential to uncover some of the missing heritability in complex heritable disorders.


It has been reported that calcitonin receptor (CALCR) gene polymorphisms might be associated with calcium stone urolithiasis. Owing to mixed and inconclusive results, we conducted a meta-analysis to summarize and clarify this association.A systematic search of studies on the association between CALCR gene polymorphisms and calcium stone urolithiasis susceptibility was conducted in databases.Odds ratios and 95% confidence intervals were used to pool the effect size. Five articles were included in our meta-analysis.CALCR rs1801197 might be associated with increased risk of calcium stone urolithiasis. There is insufficient data to fully confirm the association between CALCR rs1042138 and calcium stone urolithiasis susceptibility. Well-designed studies with larger sample size and more subgroups are required to validate the risk identified in the current meta-analysis. Urolithiasis is a relatively common health problem which is likely associated with the effects of multiple genes in combination with lifestyles and environmental factors . Majority of urolithiasis is calcium stone. The calcitonin receptor (CALCR) is a 7-pass transmembrane G-protein-coupled receptor which reacts in response to the calcium metabolism-related hormone calcitonin (3). By binding calcitonin receptor on the osteoclasts in the bone and the renal tubular cells, calcitonin causes inhibition of bone resorption and lowers serum calcium concentration (4). Therefore, calcitonin receptor gene polymorphisms might cause calcium metabolic disorders. Some calcitonin receptor gene polymorphisms, like SNP rs1801197 (1377C>T) and rs1042138 (3’UTR+18C>T), have shown association with bone mineral density . The SNP rs1801197 alters the encoded amino acid from proline to leucine (7). Researchers have also investigated the association of those SNPs with urolithiasis.Association between calcitonin receptor gene polymorphisms and calcium stone urolithiasis susceptibility has been studied in several populations. Sample sizes in these studies are relatively small. Therefore, we decided to perform a meta-analysis to estimate it.A systematic search in Pubmed by Medline, Embase, Cochrane Library, clinicaltrials.gov, CNKI  databases were carried out by two independent investigators. The following terms were used: “calcitonin Receptor OR CTR OR CALCR” AND “stone OR calculus OR calculi OR lithiasis OR Nephrolithiasis OR urolithiasis” AND “polymorphisms OR polymorphism”, without any limitation applied. The last search update was performed on August 3, 2017. References of related studies and reviews were also manually searched for additional studies.Studies selected in this meta-analysis should have met the following inclusion criteria: (1) evaluation of the association between calcitonin receptor gene polymorphisms and calcium stone urolithiasis susceptibility; (2) case-control study; (3) studies focusing on tissues of human beings; (4) detailed genotype data could be acquired to calculate the odds ratios (ORs) and 95% confidence intervals (95% CIs). Exclusion criteria: (1) duplication of previous publications ; (2) comment, review and editorial; (3) study without detailed genotype data; (4) GWAS; (5) studies focusing on cell lines. Dissertation thesis were included in the analysis.Study selection was achieved by two investigators independently, according to the inclusion and exclusion criteria by screening the title, abstract and full-text. Any dispute was solved by discussion.Two investigators extracted data of the eligible studies independently. In the case of a conflict, an agreement was reached by discussion. If the dissent still existed, the third investigator would be involved to adjudicate the disagreements. Try to contact the author by email for detailed genotype data.The following contents were collected: first author’s surname, year of publication, chemical composition of urinary calculi, the characteristics of cases and controls, source of control groups, country of origin, the detective sample, ethnicity, genotyping method, Hardy-Weinberg equilibrium, number of cases and controls for each genotype.The qualities of included studies were evaluated independently by two investigators according to Newcastle-Ottawa Scale (NOS) (8) and the most important factor was ”age, gender and country”. Quality scores range from 0 to 9, and higher scores meant better quality of the study. Disagreement was resolved through discussion.Our meta-analysis was conducted according to the PRISMA checklists (9). Hardy-Weinberg equilibrium (HWE) was evaluated for each study by Chi-square test in control groups, and P <0.05 was considered as a significant departure from HWE. OR and 95% CIs were calculated to evaluate the strength of the association between calcitonin receptor gene polymorphisms and calcium stone urolithiasis susceptibility. Pooled ORs were obtained from combination of single studies by allelic comparison (T vs. C), dominant model (CT+TT vs. CC), recessive model (TT vs. CC+CT), homozygote comparison (TT vs. CC) and heterozygote comparison (CT vs. CC), respectively. The statistical significant level was determined by Z-test with P value less than 0.05.2 index (10). When Q-test’s P-value was less than 0.10 and/or I 2 index was more than 50%, the random-effects model (DerSimonian and Laird method) was used; otherwise, the fixed-effects model (Mantel and Haenszel method) was conducted (11).Heterogeneity was evaluated by Q-test and I B ) less than 0.05, and the P value of Egger’s test (P E ) less than 0.05 was considered a significant publication bias. All statistical analyses were performed with Stata 12.0 software . A two-tailed P <0.05 was considered significant except for specified conditions, where a certain P value was declared.Sensitivity analyses were performed towards each genetic model to evaluate effect of each study on combined ORs by sequentially excluding each study in total and in any subgroup including more than two studies. Potential publication bias was checked by Begg’s funnel (12) plots and Egger’s test (13). An asymmetric plot, the P value of Begg’s test  =0). The selection process is shown in Summary results of each genetic model are listed in Sensitivity analyses were performed in any comparison and any subgroup including more than two studies. In adult urolithiasis and its male subgroup, when study NO 1.4 or 1.5 was excluded, statistically different results were obtained in all genetic models of CALCR rs1801197. Overall, when study NO 1.1 or 1.5 was excluded, statistically different results were obtained in recessive model (TT vs. CC+CT) of CALCR rs1801197 .Less than three studies were included in PU, Female of AU, ARU, Male of ARU subgroup of rs1801197, and AU, Male of AU subgroup of rs1042138, so that sensitivity analyses could not be performed.Other results showed stability in sensitivity analyses .B ) and P value of Egger’s test (P E ) were evaluated overall . No significant publication bias was found in Egger’s test in all genetic models of CALCR rs1801197. However, in allelic comparison (T vs. C), heterozygote comparison (CT vs. CC) and dominant model (CT+TT vs. CC) of CALCR rs1801197, study NO 1.3 extended beyond the diagonal line which represents pseudo-95% CI limits about the effect estimate in funnel plot, meanwhile, the u value=1.96 (u=z in Begg’s test) in those three genetic models. In Begg’s test, 1.96 is a critical value.Begg’s funnel plot and Egger’s test were used to assess the publication bias. Symmetry of funnel plot, P value of Begg’s test , and the results showed stability in sensitivity analyses and no publication bias . SignifiIn AU and its male subgroup of rs1801197, significantly increased risk was found in heterozygote comparison (CT vs. CC) and dominant model (CT+TT vs. CC). In AU, significantly increased risk was also found in allelic comparison (T vs. C) of rs1801197. However, those results lacked stability and publication bias analyses could not be performed.In PU, Female of AU, ARU, Male of ARU subgroup of rs1801197, and AU, Male of AU subgroup of rs1042138, sensitivity analyses and publication bias analyses could not be performed.Meanwhile, the limitations of this meta-analysis need to be addressed. To date, the number of available studies which could be included in this meta-analysis were small. Data for subgroup analyses were scanty. Sensitivity analyses and publication bias analyses could not be performed in some groups or subgroups. Studies NO 1.4, 1.5 and 1.5.1 had shown significant departure from HWE. Related studies published in other languages or unpublished were possibly missed. With those limitations, the study provided some insights on the potential association between CALCR gene polymorphims and calcium stone urolithiasis.In conclusion, our results suggested that: CALCR rs1801197 might be associated with increased risk of calcium stone urolithiasis. There is insufficient data to fully confirm the association between CALCR rs1801197 and calcium stone urolithiasis susceptibility in pediatric urolithiasis, adult urolithiasis, adult recurrent urolithiasis subgroup and gender subgroup, and the results should be interpreted with caution. There is insufficient data to fully confirm the association between CALCR rs1042138 and calcium stone urolithiasis susceptibility, and the results should be interpreted with caution. Well-designed studies with larger sample size and more subgroups are required to validate the risk identified in the current meta-analysis.


BackgroundPost-traumatic stress disorder (PTSD) is prevalent in children, adolescents and adults. It can occur alone or in comorbidity with other disorders. A broad range of psychotherapies such as cognitive behavioral therapy (CBT) and eye movement desensitization and reprocessing (EMDR) have been developed for the treatment of PTSD.AimThrough quantitative meta-analysis, we aimed to compare the efficacy of CBT and EMDR: (i) relieving the post-traumatic symptoms, and (ii) alleviating anxiety and depression, in patients with PTSD.MethodsWe systematically searched EMBASE, Medline and Cochrane central register of controlled trials (CENTRAL) for articles published between 1999 and December 2017. Randomized clinical trials (RCTs) that compare CBT and EMDR in PTSD patients were included for quantitative meta-analysis using RevMan Version 5.ResultsFourteen studies out of 714 were finally eligible. Meta-analysis of 11 studies (n = 547) showed that EMDR is better than CBT in reducing post-traumatic symptoms . However, meta-analysis of four studies (n = 186) at three-month follow-up revealed no statistically significant difference . The EMDR was also better than CBT in reducing anxiety . Unfortunately, there was no difference between CBT and EMDR in reducing depression .ConclusionThe results of this meta-analysis suggested that EMDR is better than CBT in reducing post-traumatic symptoms and anxiety. However, there was no difference reported in reducing depression. Large population randomized trials with longer follow-up are recommended to build conclusive evidence. The definition of post-traumatic stress disorder (PTSD) has evolved over time and available criteria differ in many ways. According to the diagnostic and statistical manual of mental disorders (DSM-V), a traumatic event is defined as the exposure to actual or threatened death, serious injury or sexual violation and leading to re-experiencing, avoidance, negative cognitions and mood, and arousal . But theFew studies have reported a comparison of occurrence of traumatic events among different countries. A comparison of 16 countries found Netherlands, Colombia and the USA had the highest rates of trauma exposure while the lowest rates of exposure were found in Italy, Romania and Spain . HoweverIn the United States, the prevalence of PTSD has been estimated to be 8.3% . DiffereThe effectiveness of CBT in treating PTSD has been documented in many studies , 10. In Several recent meta-analyses have compared the efficacy of CBT and EMDR among children, adolescents and adults. A meta-analysis of 11 trials found that EMDR was slightly better than CBT in decreasing post-traumatic symptoms . While aMethodsThis systematic review and meta-analysis is carried out in accordance with guidelines issued by Preferred Reporting for Systematic Reviews and Meta-analyses (PRISMA).Literature searchOur systematic searching was limited to articles published between 1999 and December 2017. The process of identifying relevant articles began by searching for EMBASE, Medline and Cochrane Central Register of Controlled Trials. A manual search of the references list of included articles was conducted to identify any articles not retrieved by the database searches.Inclusion and exclusion criteriaOnly studies that met the following criteria were included in this meta-analysis: (1) study participants were children, adolescents or adults; (2) studies published in the English language; (3) studies that reported comparative results from randomized controlled trials of CBT and EMDR groups; (4) studies that reported a diagnosis of PTSD in accordance to DSM-V or DSM-IV or DSM-III; (4) studies that reported adequate data for calculation of design effect. The exclusion criteria were: (1) studies reporting treatment methodologies focused on conditions other than PTSD, such as depression, bipolar disorder, behavioral problems, substance abuse, psychosis, suicidal ideation, and substance dependence; (2) studies reporting other types of psychotherapies such as psychodynamic therapy, hypnotherapy, self-help, and biofeedback.SearchThe key terms used in the searching process met the guidelines of Medical Subject Heading Terms. The key words were: post-traumatic stress disorder, “PTSD”, eye movement desensitization and reprocessing, “EMDR”, Cognitive Behavioral Therapy, “CBT”. The Boolean connector AND was used to form different combinations of the keyword, see Table Study selectionAll articles identified from all the databases were imported into one Endnote library where all duplicates were removed. The unique study titles and abstracts were screened through two independent reviewers, to check if they met inclusion criteria. Studies that met the inclusion criteria were fully reviewed by a third contributor “Ramya Bachu”, to check if they reported the required data. Studies that did not report the required data were excluded.Data extractionData extraction was carried out by two reviewers “Ali Khan” and “Padma Kotapati”. A third author “Ramya Bachu” compared the data to identify any inconsistencies. Any discrepancies were resolved through consultation among all authors, which ensured accurate data extraction process. For each included article, the means, standard deviations and p values of pre-treatment, post-treatment and follow-up were extracted. Post-traumatic symptoms were measured using the PTSD reaction index (PTSD-RI), children’s response to trauma index (CRTI), child report of post-traumatic symptoms (CROPS), clinician-administered PTSD scale child/adolescent version (CAPS-CA), clinician-administered PTSD scale (CAPS), and structured interview for PTSD (SI-PTSD). Anxiety was measured using hospital anxiety and depression scale (HADS), multidimensional anxiety scale for children (MASC), state-trait anxiety inventory (STAI), and revised children’s anxiety and depression scale (RCADS-C). Depression was measured using the Beck depression index (BDI). Other extracted variables were: age, gender, CBT variants, treatment fidelity, comorbidity, co-interventions, study duration, year of publication, and methodological characteristics useful in assessing study bias.Literature searchThe number of articles found in each database through using of various key terms is shown in Table Baseline charactersThe characteristics of included studies are shown in Table Quality assessmentAll studies were assessed for risk of bias through the Cochrane tool. The risk of bias was defined as low, medium, high, and unclear. All studies reported random sequence allocation. There was a high risk of bias in four studies regarding blinding of the outcome. Only four studies reported allocation concealment. Detailed risk of bias assessment is shown in Table Meta-analysis of post-traumatic symptoms post-treatmentPooling 11 studies in a meta-analysis, the EMDR was better than CBT in reducing post-traumatic symptoms [SDM (95% CI) = -0.43 (-0.73 – -0.12)]. The results were statistically significant (p = 0.006); however, the studies included in this quantitative meta-analysis had a high level of heterogeneity (I2 = 62%) mentioned in Figure Meta-analysis of PTSD symptoms at three months follow-upAt three months follow-up, the meta-analysis of four studies showed that EMDR was not better than CBT in reducing post-traumatic symptoms  mentioned in Figure % CI = -0Meta-analysis of anxiety post-treatmentThe meta-analysis of five studies including 239 patients revealed that EMDR is better than CBT in reducing anxiety symptoms [SDM (95% CI) = -0.71 (-1.21 – -0.21)]. The result was statistically significant (p = 0.005) but there was marked heterogeneity between included studies (I2 = 70%) in Figure Meta-analysis of depression post-treatmentThe meta-analysis of depression symptoms was based on eight studies. The meta-analysis showed that EMDR was not better than CBT in reducing depression . Also, the included studies had a high incidence of heterogeneity (I2 = 70%). These results are shown in Figure 5% CI = -Meta-analysis of depression at three months follow-upMeta-analysis of three studies at three months follow-up showed that EMDR was not superior to CBT in reducing depression symptoms . Also, the included studies had a high incidence of heterogeneity (I2 = 58%) in Figure The objectives of this meta-analysis were to compare the efficacy of EMDR and CBT in alleviating post-traumatic symptoms, anxiety and depression. The key result of this meta-analysis is, participants treated with EMDR had better alleviation of post-traumatic symptoms as compared to participants treated with CBT (p = 0.006). However, the superiority of EMDR at three months follow-up was not evident. The EMDR also had a statistically significant superiority over CBT (p = 0.005) in alleviating anxiety. Although EMDR was observed to be better than CBT in reducing depression, this difference was not statistically significant.These findings have similarities and differences with the findings of other meta-analyses comparing EMDR and CBT. A meta-analysis by Moreno-Alcazar et al. found that EMDR was better than CBT in reducing post-traumatic symptoms among children and adolescents (p = 0.013) . HoweverThe results of the meta-analysis by Lee and Ho (2012) and Davidson and Parker (2001) found inconsistent results with the current meta-analysis on the efficacy of EMDR and CBT , 30. TheOur meta-analysis declared no difference between CBT and EMDR post-treatment in alleviating depression, which is incompatible with the findings of Seidler and Wagner (2001) who found that EMDR was better than CBT in reducing depression symptoms. Of note, the meta-analysis by Seidler and Wagner included seven studies while the current analysis meta-analyzed eight studies. Additionally, in agreement with the findings of Seidler and Wagner (2001), the meta-analysis by Ho and Lee (2012) found that the EMDR was better than TF-CBT in alleviating depression. In contrast, the concept that no difference between EMDR and CBT in alleviating depression was consistent with the findings of Moreno-Alcazar et al. (2012) who did not find a statistically significant difference.Regarding reducing anxiety, the current meta-analysis reported that EMDR was better than CBT in alleviating anxiety, which is consistent with the findings of Moreno-Alcazar et al. (2017) who also found a statistically significant difference.When translating the findings of this meta-analysis into clinical practice, there are several limitations that need to be considered. For instance, there are few numbers of included participants in the analyzed randomized trials. We also searched only three major databases; however, we considered the manual searching to cover more articles. The subgroup meta-analysis of post-traumatic symptoms and depression at three months follow-up, comprised a few number of analyzed studies. Our inferences must be interpreted cautiously due to the presence of bias in more than one domain of included trials. We also did not conduct meta-regression of various variables such as age and sex due to a small number of included studies. Future large-scale randomized trials are warranted with longer follow-up periods and adherence to well-designed protocols.The results of this meta-analysis suggested that EMDR is better than CBT in reducing post-traumatic symptoms and anxiety. However, there was no difference reported in reducing depression. Large population randomized trials with longer follow-up are recommended to build conclusive evidence.


Neuregulin 4 (Nrg4) was proven as a brown fat-enriched secreted factor that can regulate glucose and lipid metabolism. However, the association between circulating Nrg4 levels and diabetes mellitus (DM) in human remains unclear. We conducted a meta-analysis to investigate association of circulating Nrg4 with DM.Observational studies comparing circulating Nrg4 levels in diabetes patients and health controls were included. Circulating Nrg4, correlation coefficients of clinical indices and circulating Nrg4 were pooled by meta-analysis.P = 0.143). However, diabetes patients had higher circulating Nrg4 than their controls in cross-sectional studies . None of the renal function and metabolic syndrome markers were correlated with circulating Nrg4, whereas the HbA1c and BMI were positively correlated .Seven studies were included. The pooled results indicated there were no significant difference in the circulating Nrg4 between diabetes patients and controls (SMD = 0.18, 95%CI = -0.06 to 0.42, Our findings suggested circulating Nrg4 may play a role in in the development of DM in cross-sectional studies and circulating Nrg4 might be associated with imbalance in glucose metabolism and obesity. It is well known that adipose tissue contributes to systemic energy balance and metabolic homeostasis. White adipose tissue (WAT) stores fat and interacts with the central nervous system and other peripheral tissues, brown adipose tissue (BAT) serves a role on defense against cold and energy excess –3. Recenhttp://www.opengrey.eu/ and http://www.ntis.gov/.We searched the PubMed, Embase, Web of Science databases from establishment to July 2, 2019 using the terms ‘‘diabetes” or ‘‘diabetes mellitus” or ‘‘DM” and ‘‘neuregulin 4” or ‘‘Nrg4” or ‘‘adipokine”. We selected only English-language, and the reference lists of identified publications were hand-examined, and the grey literature or ongoing relevant studies were searched on Cross-sectional studies and case control studies comparing circulating Nrg4 levels in diabetes patients and health controls were included. The primary outcome was the association between circulating Nrg4 levels and DM. The second outcome was correlation coefficients between circulating Nrg4 levels and the measured clinical indices in subjects with DM. The clinical indices include DM markers (fasting plasma glucose (FPG); HOMA-IR, hemoglobin A1c (HbA1c)), renal function markers (estimated glomerular filtration rate (eGFR), creatinine), metabolic syndrome markers (systolic blood pressure (SBP), diastolic blood pressure (DBP), low-density lipoprotein (LDL-C), high-density lipoprotein (HDL-C), triglyceride (TG), total cholesterol (TC)), obesity markers (body mass index (BMI), waist circumference (WC)). Studies were excluded for the following reasons: publication of abstracts, duplicate data, overlapping population, unavailable data, literature reviews, animal experiment, and case report.The information extracted from each original study by two investigators (Y.W. and S.H.), the name of first author, publication year, country, the number of subjects, mean age, circulating Nrg4 levels and correlation coefficients between Nrg4 and the measured clinical indices dealt by spreadsheets of Microsoft Excel. If there were opposite views between the two investigators, the discrepancy would be resolved through discussion. Moreover, one of the investigators would email the authors of the enrolled articles to get more information if data were absent.I2 test was used to examine heterogeneity among the studies, I2 values of 25–50%, 50–75% and 75% are considered indicative of low, moderate and high heterogeneity, respectively  was performed to transform correlation coefficient to an almost normally-distributed variable fisher’s z with SE (SE = 1/√(n-3)), where n is the sample size of diabetes patients. After these conversion, forest plots could be established to show the summary fisher’s z (Zs) and its 95% confidence intervals (CIs) [s was converted to the summary correlation coefficient (rs) by the transformation shown in equation: rs = e2Zs-1/e2Zs+1.Besides, as for the association between circulating Nrg4 levels and clinical indices in diabetes patients, Spearman correlation coefficients were selected for present meta-analysis, because they are unaffected by monotonic transformations. Pearson correlation coefficients could transform into Spearman correlation coefficients by equation: rfficient . Aiming ls (CIs) . SubsequNewcastle-Ottawa Quality Assessment Scale (NOS) was used to assess the quality of case-control studies , while, Overall, 165 studies were identified in our initial search, of which 12 underwent full-text review . FinallyP value of heterogeneity between these studies was significant, so we used the random-effect model indicating that there was no significant statistical difference between diabetes patients and their normal controls  (P<0.001). Moreover, subgroup analysis according to region and age demonstrated that no significant difference of circulating Nrg4 levels between two groups was recorded. The sensitivity analysis presented a robust result that was not influenced by individual studies. Neither the Begg’s (P = 0.548) test nor the Egger’s (P = 0.316) test showed publication bias.There were seven studies –26 regar= 0.143) . The ress = 0.12, 95% CI = -0.12 to 0.36, P = 0.330 and rs = 0.02, 95% CI = -0.15 to 0.19, P = 0.806, respectively) . Subgroup analysis had not found the sources of the significant heterogeneity. Based on sensitivity analysis, the most influential study by Kurek Eken M [P = 0.005) (P = 1.000) test nor the Egger’s (P = 0.708) test showed publication bias.Six studies –21,23–26ctively) . No publk Eken M  was excl= 0.005) , neithers = -0.14, 95% CI = -0.30 to 0.03, P = 0.099 and rs = -0.04, 95% CI = -0.21 to 0.13, P = 0.624; respectively)  and creatinine were each discussed in two of the included studies. It was found that eGFR and creatinine were no significantly correlated with circulating Nrg4 (rctively) . No publs = -0.01, 95% CI = -0.07 to 0.05, P = 0.735 and rs = 0.05, 95% CI = -0.07 to 0.05, P = 0.740, respectively)      . Also, t= 0.463) , high-de= 0.882) , triglyc= 0.238)  and tota= 0.900)  were nots = 0.11, 95% CI = -0.10 to 0.33, P = 0.301). Subgroup analysis did not find the sources of the significant heterogeneity. Based on sensitivity analysis, the most influential study by Cai C [P = 0.003) (P = 1.000) and Egger’s (P = 0.830) tests. Waist circumference (WC) was measured in two studies [s = 0.02, 95% CI = -0.26 to 0.30, P = 0.883) (P = 1.000) test.There were four included studies , 23–24 dby Cai C  was omit= 0.003) . There w studies –21, and = 0.883) . There wIt is well known that BAT could enhance energy expenditure through adjusting whole-body energy balance . MeanwhiOur study is the first meta-analysis to investigate the association of Nrg4 with DM and clinical indices, indicating that circulating Nrg4 levels were not significantly associated with DM, but subgroup analysis according to study type demonstrated that circulating Nrg4 levels were higher in diabetes patients than their normal controls in the cross-sectional study group. Furthermore, neither renal nor metabolic syndrome markers was related to Nrg4, and HbA1c and BMI were positively associated with circulating Nrg4.In our meta-analysis, circulating Nrg4 levels are not associated with the risk of DM. Contrastingly, Chen  demonstrThe indices of the renal function and metabolic syndrome were not correlated with circulating Nrg4 levels in diabetes patients. Whereas the meta-analysis suggested that circulating Nrg4 levels were positively correlated with one of the glucose parameters (HbA1c), this finding was similar to some researchers , 23. TheAdditionally, a positive correlation between adiposity proxies and circulating Nrg4 levels was confirmed in the meta-analysis. Intriguingly, Wang’s study encapsulated a negative correlation between obesity and adipose Nrg4 mRNA , and CaiIn our meta-analysis, although we observed higher levels of circulating Nrg4 in diabetes patients in the cross-sectional studies, only one case-control study investigated this correlation , which sOur meta-analysis had some strengths. First of all, we evaluated the association of circulating Nrg4 levels with the risk of DM and glucose-related/non-glucose-related parameters in diabetes patients in the round, which added to the evidences on the role of circulating Nrg4 in human metabolism. Second, our meta-analysis could avoid some potential bias, because that results of stratification according to age and region still demonstrated no significant association between circulating Nrg4 levels and DM. Several limitations cannot be avoided in our meta-analysis. Firstly, the limited studies on this correlation could influence the strength of our meta-analysis conclusions. Secondly, the most of studies were based on cross-sectional data with a limited sample size, and given its cross-sectional design, it could not confirm the causal association between circulating Nrg4 levels and DM. Thirdly, the enrolled articles were all observational studies. The possibilities of selection and confounding bias could not be avoided. Indeed, diabetes patients could differ from their health controls in terms of economic power, access to healthcare services, attention to their own health and quality of our life. Finally, the included studies were lack of more useful markers of the metabolic syndrome, such as Visceral Adiposity Index (VAI) and Lipid Accumulation Product Index (LAP), which are more realistic than HOMA, BMI or WC. Therefore, more powerful original research with new and realistic markers of metabolic syndrome are warranted to elucidate the exact role of circulating Nrg4 in the development of DM in larger samples and in other ethnic groups.In summary, although our meta-analysis suggested circulating Nrg4 levels didn’t play a role in the process of DM, subgroup of the cross-sectional study revealed that circulating Nrg4 is higher in diabetes patients. As for clinical indices in diabetes patients, the glucose and adiposity parameters were positively associated with circulating Nrg4. The exact role of the circulating Nrg4 levels in the development of DM still needs to be further identified.S1 Checklist(DOC)Click here for additional data file.S1 Table(DOC)Click here for additional data file.S2 Table(DOCX)Click here for additional data file.


Data on survival and prognosis factors in incident cohorts are scarce in systemic sclerosis (SStc). To describe survival, standardized mortality ratio (SMR), and prognosis factors in systemic sclerosis (SSc), we analyzed a multicenter French cohort of incident patients and performed a systematic review of the literature and meta-analysis.A multicenter, French cohort study was conducted between January 1, 2000, and December 31, 2013. Patients were followed-up until July 1, 2016.A systematic review of the literature was carried out in MEDLINE and EMBASE up to July 2017. Meta-analysis was performed using all available data on SMR and hazard ratios of prognosis factors.A total of 625 patients  were included. During the study period, 104 deaths (16.6%) were recorded and 133 patients were lost to follow-up. Overall survival rates at 1, 3, 5, and 10 years from diagnosis were 98.0%, 92.5%, 85.9%, and 71.7% respectively in the French cohort. Overall SMR was 5.73 (95% CI 4.68–6.94). Age at diagnosis > 60 years, diffuse cutaneous SSc, scleroderma renal crisis, dyspnea, 6-min walking distance (6MWD), forced vital capacity < 70%, diffusing capacity of the lungs for carbon monoxide < 70%, pulmonary hypertension (PH), telangiectasia, valvular disease, malignancy, anemia, and CRP > 8 mg/l were associated with a poorer survival after adjustment.Eighteen studies  were included in the SMR meta-analysis and 36 studies  in the prognosis factor analysis. Pooled SMR was 3.45 (95%CI 3.03–3.94). Age at disease onset, male sex, African origin, diffuse cutaneous SSc, anti-Scl70 antibodies, cardiac and renal involvement, interstitial lung disease, PH, and malignancy were significantly associated with a worse prognosis. Anti-centromere antibodies were associated with a better survival.Overall, our study highlights a high mortality rate in SSc patients and confirms previously described prognosis factors related to skin extension and organ involvement while identifying additional prognosis factors such as autoantibody status, telangiectasia, 6MWD, and valvular disease.The online version of this article (10.1186/s13075-019-1867-1) contains supplementary material, which is available to authorized users. Systemic sclerosis (SSc) is an autoimmune disease, characterized by microvascular damage, dysregulation of both innate and adaptative immunity, and fibrosis of multiple organs. The causes of SSc-related deaths evolved over the last decades, with cardiac and respiratory complications currently being the leading causes of death , 2.Prior cohort studies comparing contemporary and historical cohort have suggested an improvement of survival rates over time , 3, 4. YPrevious studies , 13–26 rThe aim of the present study was to fill these gaps by assessing survival and prognosis factors in a multicenter French cohort of incident SSc patients and by performing a systematic review of the literature and meta-analysis including all available prognosis factors and SMR.The French National Scleroderma Cohort includes 42 centers. The present analysis was restricted to five university hospitals, Lille, Paris (two centers), Nantes, and Lyon to ensure better quality of data, especially on survival data. These five centers participated in recruiting about two thirds of the National Cohort. Data were retrospectively collected before 2010 and then prospectively collected.Patients were included between January 1, 2000, and December 31, 2013, if they met the following inclusion criteria: (i) be aged over 18, (ii) fulfill the ACR 1980 preliminary classification criteria  or ACR/EData collected at the inclusion visit were patient demographics, history of Raynaud phenomenon (RP) and first non-RP symptom, SSc subtype and modified Rodnan skin score (mRSS), auto-antibody profile, and organ involvement.Disease onset was defined as the time of onset of first non-RP symptom. Interstitial lung disease was diagnosed on HRCT or chest x-ray. Pulmonary function tests including forced vital capacity (FVC) and diffusing capacity of the lungs for carbon monoxide (DLCO) were collected. Six-minute walking distance (6MWD) was collected. Pulmonary hypertension (PH) was suspected on a Doppler echocardiogram when systolic pulmonary arterial pressure (PAP) was estimated to be > 35 mmHg or maximum tricuspid regurgitant jet velocity > 2.8 m/s. Pulmonary arterial hypertension (PAH) was confirmed by right heart catheterization (RHC) when mean PAP was found to be ≥ 25 mmHg at rest, with mean pulmonary arterial wedge pressure ≤ 15 mmHg. EKG alterations, left ventricular ejection fraction (LVEF), diastolic dysfunction , valvulaThe meta-analysis was conducted according to MOOSE guidelines . MEDLINETwo of the authors (MRP and DL) independently screened the titles and abstracts of the retrieved records to identify eligible articles. The full text of eligible articles was read for inclusion in the meta-analysis. Selected articles were compared, and in case of disagreement, decisions were made by consensus.Cohort studies of unselected adult SSc patients assessing routine clinical and laboratory prognosis factors and SMR were included. Studies which included patients diagnosed with SSc overlap with other connective tissue diseases were excluded.Studies from the same centers were included if their respective study periods were different. If, for the same center, two studies covered an overlapping study period, data from the largest cohort were kept in the analysis. A study was recorded as an incident according to the authors’ definition.Quality of the studies was assessed using the Newcastle-Ottawa scale .Data were extracted and entered into a predefined spreadsheet table which included the following items: study design, length of follow-up, definition of disease onset, disease duration, SMR, and adjusted or, if unavailable, unadjusted hazard ratios (HR) for each studied prognosis factor.t test or Wilcoxon test in case of non-normality for quantitative variables and Fisher’s exact test for qualitative variables.Characteristics of the population were described using mean ± standard deviation or median (interquartile range (IQR)) in case of non-normality, for quantitative variables, and number (percentage) for qualitative variables. Comparisons between limited cutaneous SSc (lcSSc) and diffuse cutaneous SSc (dcSSc) patients were conducted using the Student Survival was estimated from diagnosis using the Kaplan-Meier method. Prognosis factors were assessed by Cox regression analysis in the non-adjusted analysis and subsequently adjusted for age, sex, and SSc subtype. The assumption that hazard ratios were constant over time was verified. SMR was calculated as the ratio of observed death in the cohort to the number of death of the French age/sex-matched population in 2014.I2 statistic and a chi-square heterogeneity statistic. A random-effects model was used to combine data. The overall effect was estimated using a weighted average of individual effects, with weights inversely proportional to variance in observed effects. Publication bias was evaluated with a funnel plot and Egger’s test. The pooled SMR and HR were estimated with 95% confidence interval (CI). Meta-regression was used to assess the impact of mid-cohort year, the proportion of males, the proportion of diffuse cutaneous forms, and the prevalence of anti-Scl70 antibodies on SMR. The impact of diagnosis of PH by RHC on the association of PH with mortality was evaluated. Separate analyses were performed for (i) SMR according to whether a given study included incident cases only and (ii) HR of PH diagnosed by either echocardiography and/or RHC and PH diagnosed by RHC.We calculated weighted pooled summary estimates of SMR and HR of prognosis factors. For each meta-analysis, we used the DerSimonian and Laird method. Accordingly, studies were considered to be a random sample from a population of studies. Heterogeneity was assessed using an p values less than 0.05 were considered significant.All analyses were performed using R software with the survival and metafor packages. A total of 625 patients  were included. Mean age at disease onset was 52.7 ± 14.9 years. The median disease duration from disease onset was 0.8 (IQR 2.2) years. Median follow-up time was 4.4 (IQR 5.3) years. The baseline characteristics are shown in Table During the study period, 104 deaths (16.6%) were recorded and 133 patients were lost to follow-up. Overall survival rates at 1, 3, 5, 10, and 15 years from diagnosis were 98.0% (95% CI 96.9–99.1%), 92.5% (90.4–94.7%), 85.9% (82.8–89.1%), 71.7% (66.3–77.5%), and 53% (33.8–83.4%) respectively. Survival rates for the diffuse and limited cutaneous subtypes are shown in Fig. Age of diagnosis > 60 years, dcSSc subtype, telangiectasia, scleroderma renal crisis, severe dyspnea NYHA functional classes III and IV, a shorter distance at the 6MWD, FVC < 70%, DLCO < 70%, PH, valvular disease, anemia, CRP > 8 mg/l, and cancer were associated with a worse prognosis Table .Table 2PNo association was found for digital ulcers, gastrointestinal, articular, muscular involvement, and specific auto-antibodies after adjustment.p = 0.06).Male sex showed a trend towards worse outcome, but without reaching statistical significance  < 0.001). The pooled SMR for studies including only incident patients was 3.64  < 0.001), and the pooled SMR for studies including prevalent patients was 3.28  < 0.001). There was no funnel plot asymmetry, and Egger’s test failed to provide any evidence for small study effect, making publication bias unlikely. Meta-regression stratified by study type  did not show any association with SMR (p = 0.461), meaning no statistical difference between pooled SMR of incident and prevalent studies. Subsequent analyses were therefore conducted on all studies. Meta-regression analysis revealed a significant increase of SMR with proportion of dcSSc (p < 0.001) and prevalence of anti-Scl70 antibodies (p = 0.021). There was no association with male sex (p = 0.130). There was no significant association between SMR and mid-cohort year (p = 0.656)  = 0.002). Meta-analysis of the five studies with PH defined by RHC revealed a pooled HR of 5.27  = 0.027) for mortality. Heterogeneity could not be fully explained by the use of either echocardiography or RHC alone in defining PH as revealed by meta-regression stratified by the PH diagnosis method . The presence of ACA was associated with a better survival, while the presence of joint involvement was not associated with prognosis  a high risk of mortality in our cohort of incident patients, as shown by a high SMR of 5.73; (ii) the identification of age > 60 years, dcSSc, dyspnea, PH, low FVC, low DLCO, kidney involvement, valvular disease, cancer, telangiectasia, shorter 6MWD, anemia, and inflammation as prognosis factors in our cohort; (iii) a high pooled SMR of 3.45 in the meta-analysis of the literature, including our new cohort; and (iv) the additional identification of male sex, African origin, ILD, cardiac involvement, and anti-Scl-70 antibodies as associated with worse prognosis in our meta-analysis, while ACA were associated with better prognosis.p < 0.001) and prevalence of anti-Scl70 antibodies (p = 0.021). Our high SMR of 5.73 could therefore be partly explained by the high proportion of anti-Scl70 antibodies (35%) in our population. Interestingly, there has been a debate whether or not the survival could have improved over time in SSc. Our study did not show any improvement of SMR over time, which is in line with the study of Elhai et al. [With a mid-cohort year of 2008, our study population is the largest multicenter incident and well-phenotyped cohort study of SSc patients in France and is among the most recent published to date in the literature. The overall survival rates at 5 and 10 years from diagnosis were 85.9% and 71.7%, respectively, and are lower than those reported in other recent cohorts , 44, 54.i et al. . Howeveri et al. , and SMRPrognosis factors have been assessed in many observational studies , 13–26 aBesides these well-known prognosis factors, our cohort study identifies new ones: telangiectasia, 6MWD, valvular disease, cancer, and autoantibody status.Telangiectasia was slightly associated with a higher mortality in our study population. In contrast, Poormoghim et al.  reportedThe 6MWD is a simple tool used to assess submaximal functional capacity. It is influenced by various disease parameters during SSc and lacks organ specificity . While tWhile cardiac involvement in SSc patients is robustly associated with a poor prognosis, conferring a nearly fivefold increased risk of mortality in our meta-analysis, no study had yet focused on the valvular manifestations of SSc. A recent article comparing echocardiography in SSc patients and a matched control population showed a greater frequency of valvular regurgitation and valvular replacement due to regurgitation . MoreoveAn increased incidence of malignancy has been reported during SSc, especially lung and hematological cancer . Cancer In our cohort, we did not observe any association between anti-Scl70 antibodies or ACA and survival. Interestingly, the absence of association of anti-Scl70 antibodies with survival has been suggested by numerous studies , 23, 25 The major strength of our study is the availability of detailed clinical and laboratory characteristics in a multicenter cohort of incident patients. The major strengths of our meta-analysis include (i) the first analysis of pooled HR of anti-Scl70/ACA antibodies, (ii) the separate analysis of pooled SMR in incident cohorts of SSc, and (iii) the separate analysis of pooled HR of PH diagnosed by RHC only.The main limitation is a proportion of loss to follow-up of around 20% in our cohort, despite our attempts to collect information on participants who dropped out. These patients lost to follow-up had a higher prevalence of ILD and lower prevalence of ACA at baseline, leading to potential underestimation of mortality. A second limitation is the variable definition of incident patients among studies. Although we defined incident patients as newly diagnosed ones, these patients had relatively short disease duration from first non-RP symptom diagnosis, thus minimizing survivor bias. Because of missing values, the effect of specific treatments and other data such as type and stage of cancer could not be studied, and no multivariate analysis could be performed. In addition, multiple univariate tests are responsible for an inflation of the alpha risk. However, multiple test adjustments in such exploratory study, in addition for a rare disease, are not strictly required . FinallyOur results show that mortality is still high in SSc. Strong prognosis factors identified at baseline are age at diagnosis > 60 years, dcSSc subtype, scleroderma renal crisis, severe dyspnea, FVC and DLCO < 70%, PH, anemia, and CRP > 8 mg/l. Our study also suggests the prognosis value of telangiectasia, 6MWD, valvular disease, cancer, and autoantibody status.Additional file 1: Table S1. Survival rates and survival curve for lcSSc and dcSSc. Table S2. Main characteristics of studies in the SMR meta-analysis. Table S3. Main characteristics of studies in the prognosis factors meta-analysis. (DOCX 51 kb)Additional file 2: Figure S1. Funnel plots, forest plots, and meta-regression for the meta-analysis of SMR. Figure S2. Funnel plots and forest plots of the risk factors related with mortality. (PDF 948 kb)


ALDH2 rs671 and CYP2E1 rs2031920 polymorphisms with hepatocellular carcinoma (HCC) susceptibility in East Asians.Aldehyde dehydrogenase 2 (ALDH2) and cytochrome p450 2E1 (CYP2E1) are important alcohol-metabolizing enzymes. The aim of this meta-analysis was to evaluate the association of A systematic search strategy was implemented in MEDLINE, PubMed, Scopus, Embase, and China Academic Journals databases. Nineteen case-control studies were selected for inclusion. Pooled odds ratios (ORs) and 95% confidence intervals (CIs) were calculated through random-effects or fixed-effects models. Subgroup analysis, meta-regression, sensitivity analysis, cumulative meta-analysis, and evaluation of publication bias were performed.ALDH2 rs671 and CYP2E1 rs2031920 genotypes with HCC susceptibility in East Asians. In addition, stratified analysis by country, Hardy-Weinberg equilibrium status, and source of controls also did not identify any association.The overall meta-analysis did not find a significant association of ALDH2 rs671 and CYP2E1 rs2031920 polymorphisms are not associated with HCC susceptibility in East Asians.The  Hepatocellular carcinoma (HCC) is the most common primary liver cancer and is the third most common cause of cancer-related death. In sub-Saharan Africa and some parts of Asia, it is the leading cause of cancer death. HCC most commonly develops in chronic liver disease patients, the etiology of which includes hepatitis B virus (HBV) and hepatitis C virus (HCV) infection, alcohol, aflatoxin exposure, hemachromatosis, and α1-antitrypsin deficiency [ALDH2 gene, there is a G-to-A point mutation at exon 12, resulting in a glutamic acid-to-lysine substitution at residue 487  of the ALDH2 protein (designated ALDH2*2) [ALDH2 rs671 and HCC risk in East Asians. The study by Takeshita et al. was the first study to evaluate the association of ALDH2 rs671 with HCC susceptibility, finding no association of the ALDH2 genotypes with HCC development [ALDH2 rs671 might modify the risk for developing HCC [Aldehyde dehydrogenase 2 (ALDH2) is a mitochondrial enzyme, which is known for its role in alcohol detoxification. It has the highest affinity for acetaldehyde (ACE) and mediates the rate-limiting step of metabolizing ACE to acetic acid. In addition, ALDH2 metabolizes other aldehydes generated during oxidative stress such as 4-hydroxy-2-nonenal (4-HNE), protecting against oxidative stress [ALDH2*2) . The rs6ALDH2*2) . There aCYP2E1 is located on chromosome 10q26.3 and consists of nine exons and eight introns. It is shown that a restriction fragment length polymorphism  in the 5′-transcriptional region may modify the CYP2E1 enzyme function or mRNA expression levels [Cytochrome p450 2E1 (CYP2E1) is also one of the important alcohol-metabolizing enzymes. It is strongly expressed in the liver but can also be found in extrahepatic organs such as the brain and kidneys . Hepaticn levels . AlthougALDH2 rs671 and CYP2E1 rs2031920 with HCC susceptibility in East Asian populations.In this study, we aim to perform a meta-analysis to assess the relationship of Searches were performed in MEDLINE, PubMed, Scopus, Embase, and China Academic Journals databases from inception to July 8, 2019, by two independent authors  sufficient data for pooling the odds ratio (OR) and 95% confidence interval (CI). Exclusion criteria were studies in languages other than English and Chinese, review articles, meeting abstracts, editorials, and animal studies.After the removal of duplicates from different databases, the titles and abstracts of the citations were carefully screened. Irrelevant papers were excluded, leaving potential studies for further full-text evaluation. The inclusion and exclusion criteria for the studies were as follows: (1) case-control studies of unrelated individuals using a population or hospital-based design, (2) evaluation of the relation of ALDH2 rs671 and CYP2E1 rs2031920). The quality of the included studies was evaluated according to the Newcastle Ottawa Scale (NOS) .Two authors extracted data from the eligible studies using a standardized template. Data were collected on first author, country of study, year, number of HCC patients and controls, demographics of HCC patients, source of controls, matching criteria, genotyping methods, and counts of genotypes and alleles , AA genotype vs. GA + GG genotype , AA genotype vs. GG genotype , and GA genotype vs. GG genotype . The meta-regression results for rs2031920 were similar. Next, we conducted the Galbraith plot and accordingly singled out the studies of Tomoda et al. [Phet = 0.247, I2 = 22.9%), without significantly influencing the pooled ORs. For rs2031920, removing the studies by Meng et al. [Phet = 0.096, I2 = 39.4%) but did not alter the corresponding pooled ORs.Significant heterogeneity was found among the studies evaluating rs671 and rs2031920 Tables . We perfg et al.  significALDH2 rs671 and HCC susceptibility . To evaluate the publication bias, a funnel plot of the logarithm of effect size (logOR) against the precision for each study was generated , Hardy-Weinberg equilibrium status, and source of controls. Moreover, we conducted a cumulative meta-analysis to see how the evidence had shifted over time. These efforts did not identify any association of ALDH2 rs671 and CYP2E1 rs2031920 with HCC susceptibility. Our findings were supported by most of the included studies. Among the 11 studies evaluating ALDH2 rs671, 8 reported no association with HCC, including the study by Liu et al. which had the largest sample size (600 cases and 3221 controls) [CYP2E1 rs2031920, 9 studies did not observe any association. Yu et al. evaluated the association between CYP2E1 rs2031920 and HCC susceptibility in a Chinese population for the first time; they found no association for the CYP2E1 polymorphism [CYP2E1 rs2031920 and HCC susceptibility was also reported in several Japanese and Korean studies [ALDH2 rs671 and CYP2E1 rs2031920 were unlikely to be major contributors to HCC susceptibility in East Asian populations.This is the largest and most comprehensive meta-analysis on the relationship of  studies . The finALDH2 rs671. When these studies were omitted from the overall meta-analysis, the heterogeneity dropped down to 22.9% (Phet = 0.247), without significantly affecting the pooled ORs. Concerning CYP2E1 rs2031920, Galbraith’s test showed that the studies of Meng et al. [There was significant heterogeneity between the included studies. For exploring the potential modifiers contributing to heterogeneity, we conducted a meta-regression analysis. We showed that year of publication, country, source of controls, and sample size were not the main contributors to heterogeneity. We did not take into account other factors such as sex ratio, HBV/HCV status, and drinking habits, because not all studies reported the information. It was suggested that meta-regression was not always effective in explaining between-study heterogeneity . In addiPhet = 0.7, withoug et al.  were theALDH2 rs671 and the risk of HCC in East Asians with a total of 1231 cases and 1849 controls [CYP2E1 rs2031920, our results contrasted with those of the meta-analysis by Tian et al. which reported an association between rs2031920 and HCC susceptibility in East Asians [A previous meta-analysis by Zhou et al. reported no association between controls . Using acontrols . For CYPt Asians , 33.ALDH2 rs671 and HCC susceptibility, but we could not exclude the possibility that an interaction between ALDH2 rs671 and alcohol drinking may have a role in the development of HCC. Abe et al. found that the profile of alcohol consumption and ALDH2 rs671 had a close relation, and ALDH2 rs671 and the consumptive period affected HCC development in patients with alcoholic liver cirrhosis [ALDH2 rs671 and HCC might be significantly mediated by habitual alcohol consumption [ALDH2 rs671 and alcohol drinking contribute to HCC susceptibility.Our meta-analysis suggested a lack of association between irrhosis . In addiSome limitations of our meta-analysis should be considered. First, the eligible studies in our meta-analysis were mainly from Chinese and Japanese. There was only one study from Koreans . ChronicALDH2 rs671 and CYP2E1 rs2031920 are not associated with susceptibility to HCC in East Asians. Further, well-designed and population-based studies are needed to evaluate the potential interaction between these polymorphisms and alcohol drinking in HCC susceptibility.In conclusion, the results of our meta-analysis suggest that Additional file 1:Table S1. Database search strategy.


VDR/VEGF/IL-18/MBL and HCC by combing the results of all relevant studies.Associations between polymorphisms in vitamin D receptor (VDR)/vascular endothelial growth factor (VEGF)/interleukin-18 (IL-18)/mannose-binding lectin (MBL) and susceptibility to hepatocellular carcinoma (HCC) were already explored by many studies, yet the results of these studies were inconsistent. The aim of this meta-analysis was to better clarify associations between polymorphisms in Eligible publications were searched from PubMed, Embase, WOS, and CNKI. We used Review Manager to combine the results of individual studies.VDR rs7975232, VDR rs2228570, VEGF rs699947, VEGF rs3025039, IL-18 rs1946518, and MBL rs7096206 polymorphisms were all significantly associated with HCC in the overall pooled population. We also obtained similar significant associations for VDR rs7975232, VDR rs2228570, IL-18 rs1946518, and MBL rs7096206 polymorphisms in Asians.Thirty studies were included in this study. Combined results revealed that VDR rs7975232, VDR rs2228570, VEGF rs699947, VEGF rs3025039, IL-18 rs1946518, and MBL rs7096206 polymorphisms may confer susceptibility to HCC in certain populations.Collectively, this meta-analysis proved that  Hepatocellular carcinoma (HCC) is one of the leading causes of death all over the world , 2. AlthVDR/VEGF/IL-18/MBL or the protein structure of VDR/VEGF/IL-18/MBL, there is a possibility that this polymorphism may lead to the development of chronic inflammatory cellular injuries and also confer susceptibility to many types of malignancy including HCC.Mannose-binding lectin (MBL) and interleukin-18 (IL-18) are crucial modulators of immunological reactions, whereas vitamin D receptor (VDR) and vascular endothelial growth factor (VEGF) are vital for both immune-regulation and angiogenesis –10. So, VDR/VEGF/IL-18/MBL and HCC, yet the conclusions of these studies were somehow inconsistent [VDR/VEGF/IL-18/MBL and HCC, we designed this study to get a more credible conclusion by combing the results of all relevant studies.In the past 20 years, many studies explored associations between polymorphisms in nsistent –40. To bWe wrote this meta-analysis in accordance with the requirements of the PRISMA guideline .To retrieve eligible articles, we searched PubMed, WOS, Embase, and CNKI with keywords listed below:  and  and (“hepatocellular carcinoma” or “HCC”). The references of retrieved articles were also screened by us to identify other potentially relevant articles.VDR/VEGF/IL-18/MBL and HCC in humans; (II) Offer genotypic distribution of VDR/VEGF/IL-18/MBL polymorphisms in patients with HCC and controls; (III) full manuscript in English or Chinese is retrievable. Publications were deemed to be ineligible for inclusion if (I) not about polymorphisms in VDR/VEGF/IL-18/MBL and HCC; (II) narrative reviews, systematic reviews, or comments; (III) studies only involved HCC patients. We only included the most up to date study for analyses if duplicate publications were found during the literature search.To be included in this meta-analysis, some criteria must be met: (I) about associations between polymorphisms in VDR/VEGF/IL-18/MBL among patients with HCC and controls. P values of Hardy-Weinberg equilibrium (HWE) were also calculated.Two authors extracted the following essential information from eligible studies: (I) name of the leading author; (II) published year; (III) country of the leading author; (IV) ethnicity of involved participants; (V) number of patients with HCC and controls in each study; (VI) genotype distributions of polymorphisms in The authors used the Newcastle-Ottawa scale (NOS) to assess the quality of eligible publications . The scoTwo authors extracted data and assessed the quality of eligible studies. The authors wrote to the leadings authors for additional information if essential information was found to be incomplete.Z test was employed to assess associations between polymorphisms in VDR/VEGF/IL-18/MBL and susceptibility to HCC. The statistical significance threshold of P value was set at 0.05. We used I2 statistics to assess between-study heterogeneities. We used Random-effect models (DerSimonian-Laird method) to combine the results if I2 is larger than 50%. Otherwise, fixed-effect models (Mantel-Haenszel method) were used to combine the results [We used Review Manager to combine the results of individual studies.  results , 44. We We found 168 articles during literature searching. Forty-five articles were assessed for eligibility after excluding unrelated or duplicate articles. We further excluded eight reviews and six case series, and another one publication was excluded because of missing crucial data. Totally, 30 articles were ultimately found to be eligible for inclusion  and rs2228570  polymorphisms were found to be significantly associated with HCC in overall combined analyses. Subgroup analyses showed similar positive findings for rs7975232 (dominant comparison) and rs2228570  polymorphisms in East Asians  and rs3025039  polymorphisms were found to be significantly associated with HCC in overall combined analyses. Nevertheless, we did not observe any positive associations in subgroup analyses  polymorphism was found to be significantly associated with HCC in overall combined analyses. Subgroup analyses showed similar positive findings for rs1946518 polymorphism in East Asians , South Asians , and those with hepatitis B virus (HBV) infection   polymorphism was found to be significantly associated with HCC in overall combined analyses. Subgroup analyses showed similar positive findings for rs7096206 polymorphism in East Asians  (see Table Five studies were eligible for the estimation of associations between polymorphisms in We examined the stability of combined results by deleting one study each time and combining the results of the remaining studies. The trends of associations remained consistent in sensitivity analyses, which indicated that the combined results were statistically stable.Funnels plots were employed to estimate whether our combined results may be influenced by publication biases. Funnel plots of every comparison were symmetrical, which indicated that the combined results were unlikely to be seriously impacted by overt publication biases.VDR rs7975232, VDR rs2228570, VEGF rs699947, VEGF rs3025039, IL-18 rs1946518, and MBL rs7096206 polymorphisms were significantly associated with susceptibility to HCC in certain populations. The trends of associations remained consistent in sensitivity analyses, which indicated that the combined results were statistically stable.The combined results of this meta-analysis revealed that VDR/VEGF/IL-18/MBL, result in immune dysfunction, cause chronic inflammatory hepatocellular injury, and ultimately confer susceptibility to HCC. Thus, our meta-analysis may be statistically insufficient to observe the real underlying associations between polymorphisms in VDR/VEGF/IL-18/MBL and HCC in certain subgroups. Therefore, future studies still need to confirm our findings. Second, we noticed that most eligible studies were from Asian countries, whereas studies in other countries were highly scarce, so scholars from European and African countries should also try to examine associations between polymorphisms in VDR/VEGF/IL-18/MBL and HCC. Besides, considering the functional importance of VDR/VEGF/IL-18/MBL in regulating inflammatory reactions and angiogenesis, future studies also need to test the relationship between polymorphisms in VDR/VEGF/IL-18/MBL and other types of malignancies. Third, the etiology of HCC is very complicated, so we highly recommend further genetic association studies to explore the effects of haplotypes and gene-gene interactions on disease susceptibility [VDR/VEGF/IL-18/MBL and HCC in the very beginning. However, we did not find any study on other VDR/VEGF/IL-18/MBL polymorphisms, so we only focused on 12 polymorphisms in this meta-analysis. Fifth, it is worth noting that Zhu et al. [IL-18 polymorphisms and HCC in 2016. Based on combined analyses of eight eligible studies with 3572 subjects, they did not find any positive results regarding IL-18 polymorphisms and HCC in general or subgroup analyses. Since our pooled analyses about IL-18 polymorphisms were based on more eligible studies and larger sample sizes, our results should be more statistically robust. Nevertheless, studies with larger sample sizes are still warranted to test the genetic associations between IL-18 polymorphisms and HCC in the future.To better understand the combined results of this meta-analysis, some points should be considered. First, past basic studies revealed that all investigated polymorphisms were either correlated with altered transcription activity or protein structure –48. So, tibility . Fourth,u et al.  also perVDR/VEGF/IL-18/MBL and HCC were based on combining unadjusted findings of eligible studies due to the lack of raw data [VDR/VEGF/IL-18/MBL and HCC may also be affected by environmental factors. Unfortunately, the majority of eligible studies only focused on associations between polymorphisms in VDR/VEGF/IL-18/MBL and HCC, so we could not explore genetic-environmental interactions in this meta-analysis [Some limitations of this meta-analysis should also be mentioned. Firstly, the results regarding associations between polymorphisms in raw data . Secondlanalysis . Thirdlyanalysis .VDR rs7975232, VDR rs2228570, VEGF rs699947, VEGF rs3025039, IL-18 rs1946518, and MBL rs7096206 polymorphisms may confer susceptibility to HCC in certain populations. These results also indicated that VDR, VEGF, IL-18, and MBL may involve in the development of HCC. However, the combined results of this meta-analysis should still be verified by studies with larger sample sizes.In summary, this meta-analysis proved that Additional file 1: Figure S1. Forest plots of investigated polymorphisms.


Epidemiological studies have provided ambiguous evidence on the association between vitamin E and esophageal cancer risk. To resolve this controversy, we performed this meta-analysis. The literature was searched by using Excerpta Medica Database (EMBASE), PubMed, the Web of Science, and the Cochrane Library from the inception to April 2018. A random effect model was utilized to calculate the odds ratio (OR) with the 95% confidence interval (95% CI). Twelve articles reporting 14 studies involving 3013 cases and 11,384 non-cases were included. By comparing the highest category with the lowest category of dietary vitamin E intake, we found that dietary vitamin E intake was inversely related to esophageal cancer risk . Subgroup analysis revealed that dietary vitamin E intake had a significantly negative association with both the esophageal squamous cell carcinoma risk  and the esophageal adenocarcinoma risk . No study significantly affected the findings in the sensitivity analysis. Publication bias was discovered, however, the OR (95% CI) remained unchanged after the trim-and-fill analysis. This meta-analysis showed that the higher dietary vitamin E intake is associated with a lower esophageal cancer risk. However, the association still needs to be upheld by more large-scaled randomized controlled trials and prospective studies. Helicobacter pylori (H. pylori) infection [Esophageal cancer is the eighth most common type of cancer worldwide. With an estimated 455,784 new cases and approximately 400, 169 deaths in 2012, esophageal cancer is the sixth most common cause of death from cancer. The highest mortality rates of esophageal cancer are in Eastern Asia  and Southern Africa  in men and in Eastern Asia  and Southern Africa  in women [Vitamin E is a fat-soluble vitamin including eight homologues: four tocopherols (α-tocopherol (T), β-T, γ-T, δ-T) and four tocotrienols (α-tocotrienol (TT), β-TT, γ-TT, δ-TT). A-tocopherol, the major active form of vitamin E with strong antioxidant properties, can eliminate reactive oxygen species, inhibit carcinogenesis and tumor growth, and stimulate cancer cell apoptosis ,6,7,8. ATwo investigators independently searched the electronic databases of Excerpta Medica Database (EMBASE), PubMed, the Web of Science, and the Cochrane Library up to April 2018. The following terms were used for the search: “(Vitamin E or tocopherol or tocopherols or α-Tocopherol or γ-Tocopherol or β-Tocopherol or δ-Tocopherol) and  and (neoplasm or neoplasms or cancer or cancers or carcinoma or tumor or tumors or tumour or tumours)”. In addition, the lists of references and reviews were also searched as potential supplements. The irrelevant articles were excluded by viewing the title, abstract, and full text. If one full-text could not be viewed or downloaded from the aforementioned electronic databases, we attempted to get the full-text by searching the online academic search and full-text delivery system or by contacting the corresponding author.The inclusion criteria were the following terms: (1) cohort or randomized controlled trial (RCT) or case–control studies; (2) cases were diagnosed with esophageal cancer; (3) the dietary vitamin E intake was assessed by food frequency questionnaire and the vitamin E food composition database; (4) odds ratio (OR), hazard ratio (HR), or relative risk (RR) with their corresponding 95% confidence interval (CI) were reported or calculated; (5) detailed sample sizes were available; (6) articles were published in English; (7) as to dose–response analysis, the OR/HR/RR with 95% CI for esophageal cancer and person-years or the number of cases for each quantitative category of dietary vitamin E intake were available.The following exclusion criteria were also considered: (1) nonhuman studies, review articles, letters to editor, or case reports; (2) cross-sectional studies; (3) studies where only vitamin E supplement use or serum vitamin E level were reported instead of dietary vitamin E intake; (4) studies where OR/RR/HR with 95% CI were not reported or calculated; (5) studies where detailed sample sizes were not reported.All data were extracted independently by two researchers and the ambiguities were resolved by a third investigator. The following information was extracted: (1) the last name of the first author; (2) publication year; (3) gender and age of participants; (4) the study period; (5) country; (6) source of control; (7) study design; (8) method of identifying cases; (9) the number of cases and non-cases; (10) assessment method of dietary vitamin E intake; (11) RR, OR, or HR (95% CI) for the maximizing adjusted model for the highest versus the lowest dietary vitamin E intake; (12) the adjusted covariance for multivariate analysis.We assessed the methodological quality of included articles according to the instruction of Newcastle–Ottawa Scale (NOS) , includiI2 statistics. Generally, the 25%, 50%, and 75% of I2 values refer to low, moderate and high levels of heterogeneity, respectively [I2 > 50% and p < 0.05, a random-effect model was applied to pool OR (95% CI), if not, a fixed-effect model was used for pooling OR (95% CI) [OR, HR, and RR were used for analyzing dichotomous data in one meta-analysis. OR was a fair approximation of RR when the incidence of an event was rare. Since esophageal cancer incidence is small, OR and HR are theoretically similar to RR . Therefoectively . If I2 >(95% CI) .p-value by testing that the two regression coefficients were simultaneously equal to zero. We also calculated p-values for non-linearity by testing that the coefficient of the second spline was equivalent to zero. The details of this method have been cited previously [We performed meta-regression and subgroup analysis to explore the potential source of heterogeneity based on pathological type , geographical distribution , study type , source of control , sample size (≥500 or <500), the method for identifying esophageal cancer cases , dietary vitamin E assessment method  or unvalidated FFQ), quality score (>5 or ≤5), OR/HR/RR adjusted for age (yes or no), gender (yes or no), smoking (yes or no), drinking (yes or no), and BMI (yes or no), respectively. In addition, sensitivity analyses were also performed to explore the potential study, which greatly affected the robustness of the result. Due to different definitions of exposure categories in separate studies, a fixed-effect dose–response analysis was performed to quantitatively estimate the potential association between the increment per day for dietary vitamin E intake and the esophageal cancer risk. We recalculated the pooled OR of esophageal cancer for every 3 mg/day increment of dietary vitamin E intake through previously described methods ,20. Furteviously ,24. The eviously ,26.p values for Egger’s test and Begg’s test were less than 0.05 (p < 0.05), it indicated the publication bias existed [p value < 0.05 was considered statistically significant.Finally, Egger’s and Begg’s test were performed to assess the potential publication bias. If both of  existed . If the  existed ,29, and A total of 599 articles, 256 articles, 123 articles, and 29 articles were obtained from EMBASE, PubMed, the Web of Science, and the Cochrane Library, respectively. After removing 278 duplicate studies, 729 articles remained for viewing the titles and abstracts, and then 42 articles remained for review of the full text for eligibility. Among them, three articles reported vitamin E supplementation but did not report dietary vitamin E intake in relation to esophageal cancer, one article reported vitamin E intake from diet plus supplements, two articles reported the correlation between dietary α-tocopherol intake and esophageal cancer, one article reported serum vitamin E level in relation to esophageal cancer, three articles reported combination nutrients in relation to esophageal cancer, two articles reported vitamin E intake and upper digestive tract cancer, one article was an animal study, one article was published in German, six articles did not report OR/HR/RR or 95% CI, 11 studies were reviews, and one article was a cross-sectional study. Besides, two additional articles were obtained by screening the lists of references . FinallyAmong these articles, one article was a cohort study  and 11 aI2 = 67.5%; p < 0.001)  with significant heterogeneity (< 0.001) , Table 2p = 0.044), gender (p = 0.017), smoking (p = 0.044), and BMI (p = 0.017) was the possible source of the heterogeneity. The following covariance such as geographical distribution (p = 0.475), study type (p = 0.403), source of control (p = 0.433), sample size (p = 0.821), pathological type (p = 0.072), the method of identifying esophageal cancer cases (p = 0.463), dietary vitamin E assessment method (p = 0.394), quality score (p = 0.355), and adjustment for drinking (p = 0.261) did not explain the between-study heterogeneity.Since significant heterogeneity was found in this meta-analysis; meta-regression and subgroup analysis were performed to explore the source of the between-study heterogeneity. Meta-regression analysis found adjustment for variables like age , gender , smoking , and BMI . When controlled by pathological type, heterogeneity decreased in the EAC cases , ESCC cases , and mixed subtype cases . In general, in the cases with the highest vs. the lowest category of the dietary vitamin E intake, dietary vitamin E has a rather inverse association with both the risk of EAC  and the risk of ESCC . The detailed results on subgroup analysis are shown in In the subgroup analysis, when stratified by adjustment for variables like age, gender, smoking, and BMI, no statistical heterogeneity was found in the studies without adjustment for variables like age (p = 0.987), no significant non-linear dose–response relationship was found (pnon-linearity = 0.864), but a marginally linear dose–response relationship was found for 3 mg/day increment of dietary vitamin E intake and the risk of esophageal cancer  . Then, trim and fill analysis was performed for the adjustment of funnel plot asymmetry; no missing studies were added and the adjusted OR was 0.47 (95% CI: 0.36–0.60), which showed the pooled OR (95% CI) remained unchanged. The funnel plot of trim and fill analysis was shown in A total of four articles reporting five studies involving 970 cases and 2225 non-cases ,14,33 we= 0.114) A. For th= 0.114) . Both EgUp to now, epidemiology studies have provided ambiguous evidences for the relationship between dietary vitamin E intake and the esophageal cancer risk. To solve the divergence, we performed a meta-analysis on the association between dietary vitamin E intake and esophageal cancer risk (including EAC and ESCC). We found that the higher dietary vitamin E intake was related to a lower esophageal cancer risk, especially for ESCC. The aforementioned findings were in line with many other studies of dietary vitamin E intake and various cancer risks. One published dose–response meta-analysis has suggested that bladder cancer risk decreased by 17% for every 10 mg/day increase of dietary vitamin E intake  . AnotherIn 2007, Kubo’s meta-analysis explored the association between antioxidant intake (including vitamin E) and the risk of esophageal and gastric cardia adenocarcinoma, and showed a marginally inverse association between vitamin E intake and EAC risk , but did not report the relationship between vitamin E intake and ESCC risk . In KuboThe present meta-analysis showed that higher vitamin E intake is negatively associated with the risk of esophageal cancer. This may be explained by the strong oxidative properties of vitamin E ,44. One 2 for BMI, the esophageal cancer risk was enhanced by approximately 10%  [Based on the results of meta-regression and subgroup analysis, we found that the possible sources of between-study heterogeneity for this meta-analysis were adjustment for variables like age, gender, smoking, and BMI. As we know, the incidence of esophageal cancer increases with age, and the incidence of esophageal cancer worldwide in males is more than double that in females (2.4:1). Furthermore, one meta-analysis of 12 studies showed that about 68% esophageal cancer cases were attributed to smoking  . As for 09–1.14) ,50. The To our knowledge, the present meta-analysis had several advantages Firstly, the study was a quantitative and comprehensive dose–response analysis to evaluate the association between dietary vitamin E intake and the risk of esophageal cancer. Secondly, meta-regression and subgroup analysis were simultaneously performed to explore the potential sources of heterogeneity. Thirdly, sensitive analysis found no one specific study significantly affected the pooled OR (95% CI). Fourthly, trim and fill analysis did not find potentially missing articles, and the pooled OR (95% CI) was maintained after the adjustment of the asymmetry of the funnel plot, which revealed that our findings might be robust and sound.However, several limitations should also be taken into consideration. Firstly, most of the eligible studies were case–control studies, which were prone to cause recall bias and selection bias. Secondly, dietary vitamin E intakes were assessed by validated FFQs ,13,14,30In summary, our study suggests that dietary vitamin E intake is inversely associated with the esophageal cancer risk. Considering the limitations of the included studies, more large-scale prospective studies and randomized controlled trials are still needed to confirm our results, though our findings could provide certain evidence for esophageal cancer prevention.