Post-infectious bronchiolitis obliterans (PIBO), one of the major complications of respiratory tract infection, is commonly underdiagnosed. To identify the risk groups that may develop PIBO and avoid misdiagnoses, we investigated the risk factors associated with the development of PIBO. We searched PubMed, Embase, and MEDLINE databases for studies that included risk factors for the development of PIBO published from inception to 13 June 2022. We limited our search to studies that reported the estimates of odds ratio (OR), hazard ratio (HR), or relative risks for developing PIBO. A fixed-effect and a random-effect model were used. We included seven studies reporting data on the risk factors for PIBO in 344 children with PIBO and 1310 control children. Twenty-two variables, including sex, age, respiratory pathogens, symptoms, laboratory and radiologic findings, and mechanical ventilation, were mentioned in at least one study. The significant risk factors mentioned in two or more studies included elevated lactate dehydrogenase levels, pleural effusion, hypoxemia, sex, and mechanical ventilation. The significance of the duration of hospitalization and fever as risk factors for PIBO differed when the studies were classified according to the statistical method. In addition, the risk factors differed according to respiratory infection pathogens. This meta-analysis identified potential risk factors associated with the development of PIBO. The results of this study highlight the importance of avoiding misdiagnosis and help establish management strategies for patients at a high risk of developing PIBO. Mycoplasma pneumoniae (MP), can cause the development of PIBO [Post-infectious bronchiolitis obliterans (PIBO) is a chronic and irreversible obstructive airway disease that results from the insult on the small airways following a lower respiratory tract infection . The cli of PIBO .Although there is a lack of effective treatments for PIBO, a delay in the diagnosis of PIBO reduces the therapeutic effect of potential management strategies since the management strategies have limitations in reversing the progression of peribronchiolar fibrosis . TherefoThe pathophysiologies of respiratory tract infections, including adenovirus and MP, are different according to pathogens , and theThis systematic review and meta-analysis were conducted in accordance with the Preferred Reporting Items for Systematic Review and Meta-analyses (PRISMA) reporting guidelines . We searStudies satisfying all of the following criteria were included in this meta-analysis: (1) studies that included children diagnosed with PIBO according to the diagnostic criteria; (2) studies that included a control group, defined as the presence of respiratory tract infections without PIBO and patients with PIBO; (3) studies that showed complete risk estimate data and clear outcomes; (4) studies that reported estimates of odds ratio (OR), hazard ratio (HR), or relative risk (RR) with corresponding 95% confidence intervals (CIs); and (5) original articles with cross-sectional, case–control, or randomized controlled trials. Studies were excluded from the present meta-analysis if: (1) the study was a comment, case report, abstract, editorial, letter, or review; (2) there was no description of OR, HR, or RR with 95% CIs; (3) there was no accessible full text; (4) the literature was not published in English; and (5) the study had an uncertain definition for the diagnosis of PIBO.Data were collected on study author, publication year, study period, study design, study country, participants’ age, participants’ sex, diagnostic criteria for PIBO, respiratory pathogens, risk factors, and risk estimates, including RR, HR, or OR with 95% CIs. If data were missing, the corresponding authors were contacted. Two reviewers (E.L. and H.J.Y) independently screened articles for eligibility, and disagreements about whether specific articles should be included in our analyses were resolved by discussion based on a consensus.Two reviewers (E.L. and H.J.Y) independently assessed the included studies for risk of bias in a sample population, sample size, participation rate, outcome assessment, and analytical methods to control for bias using the Strengthening the Reporting of Observational Studies in Epidemiology (STROBE) reporting guidelines in five items ,7. DisagPublication bias is generally recommended when ten or more studies are included and can be evaluated from three or more studies . In the I2 statistic was used to assess heterogeneity in the results of individual studies, and an I2 > 50% was used as the threshold indicating significant heterogeneity. A p value < 0.05 was considered statistically significant. Forest plots were constructed using summary statistics for risk factors that included two or more studies. The statistical analyses were conducted using R version 3.4.1 and Rex .The estimates (OR or HR) with a 95% confidence interval (CI) in several papers were calculated for potential risk factors for the development of PIBO. We extracted the estimates and 95% CIs from the multivariate analysis. If the study provided the univariate analyses without information on the multivariate analyses, the univariate OR or HR was obtained. The extracted estimates and 95% CI were converted into beta and standard error (SE) for analysis and the meta-analysis was conducted for variables reported in at least two studies. We used a random-effect model to calculate the ORs or HRs. An Our initial literature search identified 13,358 studies . After aTwo studies used logistic proportional hazard models ,14, and All included studies were assessed for methodological quality using the Newcastle-Ottawa Scale (NOS) . The NOSThe meta-analysis was performed on three risk factors with HRs with 95% CIs A and ninThree studies indicated that males were at a higher risk of developing PIBO . One of the studies reported risk factors of PIBO developing after MP pneumonia . The remI2 = 51.9%, p = 0.124).Two studies reported the relation between LDH levels and the development of PIBO after MP infections, which showed that higher LDH levels, measured at the time of MP infection, were associated with the development of PIBO . There was no significant heterogeneity .A pleural effusion during MP infection was associated with the development of PIBO . The heterogeneity was not significant .Two studies reported the association between hypoxemia and PIBO development  ,13. One Four studies reported the association between mechanical ventilation and PIBO development ,12,14,15A meta-analysis of two of the studies on PIBO cases that developed after an adenovirus infection showed no significant association between the duration of fever and the development of PIBO, using a logistic proportional hazard model ,14. HoweFour studies reported the association between the length of hospitalization and PIBO development ,12,13,14Two studies showed the association between an adenovirus infection and PIBO development using multivariate logistic regression analysis ,15. One Three studies described the association between age (months) and the development of PIBO ,13,15. OThis systematic review and meta-analysis investigated the risk factors associated with the development of PIBO from seven studies that included HR or OR to minimize the heterogeneity arising from the diversity of the presented methods of the results in each study. Our meta-analysis showed that LDH levels, pleural effusion, hypoxemia, sex, and mechanical ventilation are risk factors for the development of PIBO among 9 variables that were mentioned in more than two studies. The significance differed for the length of hospitalization and duration of fever as risk factors for PIBO according to the statistical method used. In addition, the risk factors for developing PIBO differed according to the respiratory pathogen. The results of this study are helpful in the recognition of high-risk individuals that require follow-up to detect the development of PIBO with consideration of the respiratory pathogens and thereby improving the clinical outcomes of PIBO.The pathogenesis of respiratory epithelium insults with related immune responses in response to respiratory infections differs according to the respiratory pathogens , which eIn association with the causative respiratory pathogens of the development of PIBO, adenovirus infections  and adenIn addition, host immunity and immunopathology against respiratory pathogens might affect the development of PIBO . Among tRegardless of respiratory pathogens as potential risk factors for PIBO, hypoxemia, mechanical ventilation, sex, and longer duration of fever and hospitalization were associated with increased risks for PIBO, when analyzed using logistic regression analysis. These findings suggest that severe and increased disease burden is related to the development of PIBO. Therefore, it is necessary to follow up with concerns on whether PIBO occurs after severe respiratory infections with increased disease burden resulting in respiratory tract infections.This study has several limitations. First, the number of studies included in the meta-analysis was small. As clinical manifestations of PIBO are diverse, the period between onset and identification of PIBO by physicians varies from patient to patient, and the diagnosis of PIBO is often missed. The missed diagnoses lead to PIBO being reported as a rare disease , althougIn conclusion, we identified potential risk factors for the development of PIBO in children. Children with potential risk factors during respiratory tract infections are required follow-ups for the development of PIBO. These results can be useful in not missing a diagnosis of PIBO in children and therefore would help improve the clinical outcomes in children with PIBO.


Schizophrenia has been robustly associated with multiple genetic and environmental risk factors. Childhood adversity is one of the most widely replicated environmental risk factors for schizophrenia, but it is unclear if schizophrenia genetic risk alleles contribute to this association.CRD42020182812). Following PRISMA guidelines, a search for relevant literature was conducted using Cochrane, MEDLINE, PsycINFO, Web of Science, and Scopus databases until February 2022. All studies that examined the association between schizophrenia PRS and childhood adversity were included.In this systematic review and meta-analysis, we assessed the evidence for gene-environment correlation  between schizophrenia polygenic risk score (PRS) and reported childhood adversity. We also assessed the evidence for a gene-environment interaction  in relation to the outcome of schizophrenia and/or psychosis. This study was registered on PROSPERO , but the effect was small and therefore likely to explain only a small proportion of the association between childhood adversity and psychosis. The 4 studies that investigated a gene-environment interaction between schizophrenia PRS and childhood adversity in increasing risk of psychosis reported inconsistent results.Seventeen of 650 identified studies met the inclusion criteria and were assessed against the Newcastle-Ottawa Scale for quality. The meta-analysis found evidence for gene-environment correlation between schizophrenia PRS and childhood adversity (These findings suggest that a gene-environment correlation could explain a small proportion of the relationship between reported childhood adversity and psychosis. A large meta-analysis across prospective cohorts, case-control, and cross-sectional design studies found that patients with psychosis were 2.78  times more likely to report being exposed to childhood adversity or trauma than controls.22 Furthermore, this association has demonstrated a “dose-effect” whereby as the severity of the childhood trauma increased, so did the likelihood of developing psychosis.21Environmental risk factors have also been shown to contribute to the likelihood of developing schizophrenia; evidence exists for illicit drug use (in particular cannabis),correlation, and/or via gene-environment interaction. 23 An evocative gene-environment correlation describes the association between a child’s genetically influenced behavior and the reaction from others in their environment to that behavior.24 Lastly, an active gene-environment correlation indicates an association between an individual’s genetically influenced traits and the selection of specific environments (such as a shy child seeking a different environment to an outgoing child). Twin and adoption studies have highlighted the importance of gene-environment correlations and interactions in human genetic research.25 The presence of a gene-environment correlation suggests that genetics may be a confounder that explains, at least in part, why an environmental risk factor is associated with a disorder or outcome. A gene-environment interaction alternatively suggests that an individual’s genetics can control (moderate) how sensitive they are to environmental exposures and whether those exposures will increase the risk of an outcome.27Although evidence indicates that schizophrenia arises from both genetic liability and environmental exposures, how these risk factors combine to ultimately lead to disorder remains unclear. There is ongoing debate about whether genetic and environmental effects act independently, are associated via gene-environment 28–30 A recent qualitative review also found that childhood adversity was associated with psychosis largely independent of genetic liability.31 However, this review only included studies with individuals experiencing psychosis and where the genetic factor was analyzed as a mediator, thus limiting the studies that were included.The first studies investigating the relationship between genetic risk and childhood adversities used twin and family designs and found significant within-pair differences, indicating that at least part of the association between childhood trauma and psychosis is likely to be causal and not driven by gene-environment correlation.The aim of the current study was to conduct a systematic review and meta-analysis of the existing literature from both population and clinical samples investigating the gene-environment correlation between schizophrenia polygenic risk and reported childhood adversity. To our knowledge, this is the first quantitative review of this evidence. Secondly, we aimed to summarize the evidence regarding gene-environment interaction between schizophrenia polygenic risk and childhood adversity for the outcome of psychosis or schizophrenia case/control status. Better understanding the relationship between schizophrenia risk alleles and childhood adversity may enhance our knowledge of the mechanisms underpinning the development of psychosis and schizophrenia.32 and include maltreatment, domestic violence, assault, physical, sexual, emotional, or psychological abuse, neglect, bullying, discrimination, violence, victimization, parental loss, and bereavement. Broad definitions were used to try and capture as many studies as possible.We define childhood adversities as events that present a serious threat to a child’s physical or psychological well-being,https://www.crd.york.ac.uk/prospero/display_record.php?ID=CRD42020182812) and the PRISMA guidelines for reporting systematic reviews were followed33 AND OR (bullied OR bullying) OR victim* OR victimization OR parental loss OR bereave OR parental death* OR adopt* OR in care)) AND ((schiz* OR psychosis) AND (polygenic risk score OR PRS OR polygenic risk OR polyrisk score OR genome wide association stud* OR GWAS OR genetic score OR risk profile score OR genetic risk score OR genomic risk score OR GRS OR polygenic hazard score)).We searched Cochrane, MEDLINE, PsycINFO, Web of Science, and Scopus databases from January 2007, when the first psychiatric GWAS was conducted,All studies that measured an association between schizophrenia PRS and childhood adversity were included see . InteracP-value thresholds. Individual studies were assessed for quality using the Newcastle-Ottawa Scale for Quality of Observational Studies.36Initially, relevant titles and abstracts were identified independently by 2 researchers (G.E.W. and S.E.S.). Where the title and abstract were insufficient to determine eligibility, the full articles were obtained. The following data were extracted: author, publication type, study characteristics, number of participants, participant characteristics, method of recruitment, measurement of childhood adversity, effect size and standard error, power, and PRS We split the included studies into 2 groups based on the sample in which the research was conducted: (1) population studies and (2) clinical studies. We defined clinical studies as those that recruited patients with a diagnosis of schizophrenia or a related psychotic disorder  and population studies at those that have recruited participants from the general population.metafor37 package in R. It was not possible to conduct a meta-analysis for gene-environment interaction due to the limited number of studies and different statistical models used. A 3-level meta-analysis was used to account for the nested structure in the data, whereby several childhood adversity outcomes were reported in the same study samples. Sample (as opposed to study) was used to define one level due to several studies being conducted in the same sample, for example, the Avon Longitudinal Study of Parents and Children (ALSPAC). Odds ratios and beta were first converted to standardized mean differences (Cohen’s d), and then to Pearson’s correlation coefficients using the effectsize38 R package to allow dichotomous and continuous data to be combined.40 If childhood adversity was analyzed as both a continuous and a binary variable, we selected the results from the continuous analysis to include the greatest amount of data.38 If studies reported multiple levels of adjustment, we extracted the most adjusted effect size (excluding other PRS scores).Where multiple PRS P-value thresholds were reported, we selected P <.05, given this threshold explains the most variance in schizophrenia case-control status.3 If this threshold was not available, or another PRS method was used, we selected the PRS that explained the most variance in childhood adversity. We excluded results from analyses involving PRS from multiple disorders or traits. Heterogeneity was assessed per level of the meta-analysis and meta-regression was used to explore possible causes of heterogeneity. Sensitivity analyses were also conducted to assess the effect of adding moderators into the analysis. Publication bias was assessed using funnel plots. Meta-analysis results are presented in a forest plot by population in which the effect size was reported.A multilevel meta-analysis of peer-reviewed studies investigating a gene-environment correlation was conducted using the 36 , but effect sizes found were small. Studies in clinical samples reported inconsistent findings and were hampered by small sample size.There was variability in the way childhood abuse was defined in the included studies. Childhood adversity was considered as a broad definition  either in binary form or on a continuous scale, or as more specific forms such as bullying or abuse . First, P = 8.4E-6) and in the Norwegian Mother, Father and Child Cohort Study .42 A study in a sample of 3963 unrelated twins (Twins Early Development Study) found retrospectively self-reported childhood trauma to be associated with higher schizophrenia PRS .43 Furthermore, a prospective birth cohort (Generation R) of 1901 participants found schizophrenia PRS to be associated with maternal reports of childhood adversity  which the authors replicated in the ALSPAC cohort .44 Further analyses demonstrated that this association was driven by childhood adversities occurring before the age of 5 years . A study of 5947 participants from a university student population (age 18–22) found that schizophrenia PRS predicted a report of previous trauma, although the study is limited by its retrospective nature and the lack of information on the timing of the trauma.45In one of the largest studies conducted, Sallis et al assessed any adversity across childhood and adolescence and found an association with schizophrenia PRS in both the Avon Longitudinal Study of Parents and Children longitudinal cohort .46 Finally, 2 clinical studies48 assessed the relationship between global childhood adversity and schizophrenia PRS in their control samples and both found positive associations, although only one was statistically significant.44 These studies are discussed further in the “Clinical Studies” section.No association was found in 593 twins, where schizophrenia PRS and childhood adversity were investigated to understand the influence on momentary mental state domains .49 A subsequent follow-up study in this sample including data from age 13, however, reported a positive association with schizophrenia PRS .50 A further study in ALSPAC, using a range of questionnaire responses collected throughout childhood and adolescence, reported no association between bullying and schizophrenia PRS; however, evidence was found for an association in MoBa  which assessed sibling violence (occurring in the home environment),42 suggesting there could be qualitative differences between sibling and peer bullying. The final study investigating bullying victimization24 in 650 participants through peer nomination scores reported a significant association with schizophrenia PRS at 14 years of age.24 In addition, the researchers found bullying victimization mediated the relationship between schizophrenia PRS and later psychotic experiences.24 The variability in definitions of adverse peer experiences across these studies is also likely to have contributed to the inconsistent findings reported. Bullying and peer victimization have been shown to be qualitatively different experiences, with bullying being more severe.51Bullying and peer victimization are the most researched specific forms of childhood adversity in population-based research studies. A large study in 8365 participants from ALSPAC found that schizophrenia PRS was not associated with exposure to child victimization , feeling hated by a family member as a child , and were less likely to report feeling loved as a child  or that they had someone to take them to the doctors as a child .52 The second study used a twin cohort of 6710 participants to explore parental smacking during childhood and found no evidence of an association between schizophrenia PRS and parent smacks or slaps as a child .53 Thirdly, a recent study of a cohort of 13 313 female nurses found schizophrenia PRS was associated with a higher risk of experiencing physical or emotional abuse  and physical assault  but not sexual abuse .54There are 3 studies that have explored other specific childhood adversities. Trauma questionnaire responses were examined in 334 976 participants in the UK Biobank cohort.All of the studies discussed so far in the review have assessed the gene-environment correlation between schizophrenia PRS of the child and childhood adversity, but their experimental designs did not permit further dissection into the specific types of gene-environment correlation 42 and fathers showed a similar trend (OR = 1.04). It is argued by the authors that these findings provide evidence for a passive gene-environment correlation as the schizophrenia PRS in the mother was associated with her child’s adversity and thus the effects are unlikely to be driven solely by genetic effects from the child. Hypothetically, if an evocative or active gene-environment correlation was observed , a stronger effect of the child’s PRS would have been found.42 A study in 3151 adopted individuals from the UK Biobank explored the association of schizophrenia PRS with childhood adoption.55 Childhood adoption is an indicator of early-life adversity and is associated with increased rates of mental health problems (including nonaffective psychoses such as schizophrenia) in later life.56 The researchers found that for each SD increase in schizophrenia PRS, the odds of being adopted increased by 5%. The authors argue these findings indicate support for a passive gene-environment correlation, whereby the child’s genetic predisposition is associated with the child’s environment, in this case, being adopted.Sallis et al (described above) also assessed the association of childhood trauma with the schizophrenia PRS in the child’s parents in the ALSPAC and MoBa samples24 However, this mechanism has not been empirically demonstrated to date and distinguishing between different theoretical mechanisms of gene-environment correlations is challenging and requires PRS for the parents.An evocative gene-environment correlation has been frequently used as a potential explanation for how bullying could theoretically mediate the genetic risk of later psychotic symptoms, by which a child with a high schizophrenia PRS may be more likely to evoke certain behaviors such as bullying from others.Two studies investigated this question in clinical cohorts consisting of patients with a diagnosis on the schizophrenia spectrum or first-episode psychosis. A further study investigated children of parents with a schizophrenia spectrum, bipolar or major depressive disorder diagnosis.P = .02) but not in cases  when considering childhood adversity as a continuous variable.47 A further study of 80 first-episode psychosis patients and 110 controls found that while participants experiencing psychosis reported significantly more childhood adversity than controls, and patients had a higher schizophrenia PRS, the schizophrenia PRS was not significantly associated with childhood adversity in either patients  or unaffected controls .48 Lastly, a cohort of 297 children at clinical high risk due to having a parent with a diagnosis of major depressive disorder, bipolar disorder, or a schizophrenia spectrum disorder found no evidence of a significant relationship between schizophrenia PRS and peer victimization , overall adversity , or social-economic adversity .57In 384 individuals with first-episode psychosis, a recent study found an association between schizophrenia PRS and childhood adversity in 690 unaffected controls  . The observed effect was statistically significant in population-based studies   but not clinical studies  . In a multilevel meta-analysis, heterogeneity is reported per level; I2level 3 = 17.89% of the total variation was attributed to the between-cohort level, and I2level 2 = 69.73% was attributed to within-cohort heterogeneity. However, leave-one-out analyses demonstrated that one study57 was very influential and when removed from the analysis, the heterogeneity statistics demonstrated instead that just over 20% of the variance can be explained by between-cohort heterogeneity   .57 Removing these 2 studies from the meta-analysis reduced the correlation slightly but it remained significant . Moderators of population versus clinical study  and effect size reported in original study (β/OR)  were not significant when included in the meta-analysis. Prediction intervals for the overall model ranged from r = −.0213 to .0595 , and ranged from r = −.0237 to .0631  for population studies, and r = −.0415 to .0656  for clinical studies.The funnel plot indicated that the meta-analysis was unlikely to be affected by significant publication bias  but it hr = .024; 95% CI = 0.01, 0.04; P < .0001) but not for physical abuse , sexual abuse , and peer victimization  when considered separately.We conducted subanalyses of specific childhood adversities, which showed a significant association in studies reporting an overall adversity score  , emotional abuse , emotional neglect , and sexual abuse . No additive interactive effect was evident between schizophrenia PRS and physical abuse or physical neglect. The authors argued that both emotional and sexual abuse showed a “mechanistic interaction,” meaning that some individuals would only develop schizophrenia if both genetic risk for schizophrenia and emotional or sexual abuse was present, but not one alone.In 1699 schizophrenia spectrum cases and 1542 controls, Guloksuz et al47 used another method, the interaction contrast ratio (ICR) [ORexposure and PRS − ORexposure – OR PRS + 1], to assess an additive interaction. They reported evidence of a nonsignificant positive interaction between schizophrenia PRS and childhood adversity . When analyzing the interaction by subtype, the strongest interactions found were physical abuse  and physical neglect . However, all the CIs were large and included zero.Aas et alb = −0.20; SE = 0.41; P = .632).48 Lastly, a Danish twin study in 56 schizophrenia spectrum proband pairs, 49 healthy control pairs, and 6 individual probands found no evidence of an interaction between schizophrenia PRS and childhood adversity .59In 80 first-episode psychosis cases and 110 unaffected controls, Trotta et al found no evidence of an additive interaction between schizophrenia PRS and childhood adversity . Only 4 studies investigated a gene-environment interaction between schizophrenia PRS and self-reported childhood adversity on psychosis risk and reported inconsistent findings.In this systematic review and meta-analysis, we investigated the evidence for a gene-environment correlation or interaction between schizophrenia PRS and reported childhood adversity to increase vulnerability to psychosis. A total of 26 gene-environment associations were reported from 15 population-based studies. Of these, 18 showed evidence for an association at 55 The effect sizes relating to schizophrenia PRS detected in these samples were small, and the overall correlation detected in our meta-analysis was r = .02 . The small amount of variance explained demonstrates that schizophrenia PRS is making a limited contribution to the occurrence of childhood adversity. This study indicates that a gene-environment correlation is unlikely to fully explain the relationship between childhood adversity and increased risk of experiencing psychosis, although we have only assessed the contribution of common genetic risk captured by PRS and have been unable to statistically quantify the exact amount of this association that is explained by schizophrenia PRS. To definitively quantify this gene-environment correlation, consistent definitions of schizophrenia and psychosis need to be used, and the contribution of rare variation also needs to be quantified. Moreover, PRS from currently powered GWAS only capture a small proportion (around 8%) of the variance in liability for schizophrenia6; hence, any PRS estimate would provide a lower bound estimate, and more accurate estimates may be found using twin and family studies. Nevertheless, our findings are supported by earlier twin and family studies that reported significant within-pair differences,28–30 and thus suggested that at least part of the association between childhood trauma and psychosis is likely to be causal, or at least not driven by gene-environment correlation. Schizophrenia PRS has been associated with other mental health problems in adolescence aside from psychosis such as anxiety,60 indicating that the gene-environment correlation found in this study may have implications beyond the pathway to psychosis.Based on the current literature and results from this meta-analysis, there is evidence to support a gene-environment correlation between schizophrenia PRS and childhood adversity in the general population. The population-based studies providing support for a gene-environment correlation included evidence from high-quality, prospective, and large cohort studies including UK Biobank, ALSPAC, MoBa, Generation R, Nurses’ Health Study 2 (NHS2), and Twins Early Development Study (TEDS).There were only a few studies, with limited sample sizes, investigating evidence of a gene-environment correlation in individuals with schizophrenia, related psychotic disorders, or psychotic symptoms. Although the findings were not statistically significant, clinical studies seemed to follow a similar pattern of effect to the population-based studies, which was mirrored in the meta-analysis findings. Studies investigating this relationship in clinical studies could be at risk of collider bias as schizophrenia PRS and childhood adversity are both associated with psychosis. However, as the meta-analysis demonstrates the correlation in population studies, it seems unlikely to be impacting the results. The lack of evidence for a gene-environment correlation in the clinical samples is likely due to insufficient power to detect an effect but it is possible the association in clinical and population samples are not consistent.58 These findings are further supported by previous studies in twin, adoption, and family studies in schizophrenia.26 No statistically significant evidence was found in a subpopulation of first-episode psychosis cases in the same sample47 as all the CIs included zero. The 2 other studies59 did not find evidence of an additive interaction but it is likely the studies were underpowered. It is possible that other studies ran interaction analyses but did not report negative results, resulting in publication bias. However, different interaction models were used across these studies which has been demonstrated to impact consistency of findings.61 Additive and multiplicative models of interactions have different null hypotheses and interactions can be identified using one method and not using the other in certain circumstances.62 The variance in our findings are by no means unique, gene-environment interactions of complex diseases are challenging to research and difficulties are seen across the field.63 Furthermore, even when significant interactions have been observed, it has been argued that their contribution to advancing knowledge of disease is minimal.61We found inconsistent findings in the few studies that investigated gene-environment interaction between schizophrenia PRS and childhood adversity. The largest clinical sample showed an additive interaction effect between schizophrenia PRS and childhood adversity in relation to psychosis risk.36 primarily due to the use of retrospective self-reports. Given the sensitivity of childhood adversity, alternative solutions to a self-report method of data collection are at risk of other biases and so addressing this risk of bias is not simple. Retrospective reports could lead to error as people misremember over time (misclassification bias). This could be nondifferential misclassification, which could affect people equally in relation to their PRS status and almost always leads to an underestimation of an association, or differential misclassification which could affect people differently depending on their PRS. For example, those with high PRS are more likely to get schizophrenia and to develop cognitive deficits that could affect their memory,64 which could lead to either an under or overestimate of the association. Moreover, individuals who have a psychiatric diagnosis may be more likely to report childhood adversity by means of an explanation as to why they became unwell, resulting in confirmation bias. Conversely, high-quality longitudinal studies such as ALSPAC may have other forms of bias as a result of participant attrition, of relevance to this study is the association with schizophrenia PRS, that could have influenced results.65 Lastly, most of the studies included in our review measured the quantity of childhood trauma, rather than disentangling the other complexities that are involved within genetic-environment interactions such as timing, duration, severity, and extent of repeated exposures.67We found considerable inconsistencies across the literature and one of the main differences was the diverse range of childhood adversity measures used and the way in which they were scored. This may be particularly important as we found heterogeneous strengths of association based on adversity type in our meta-analysis. Even within specific adversities differences prevailed, for example, for peer victimization and bullying, a combination of peer nomination scores, teacher reports, parent responses, and child’s reports were obtained, making differences hard to interpret. We found that the measure of childhood adversity was at most risk of bias when scoring the Newcastle-Ottawa Quality Assessment Scale,6 Therefore, it is unknown whether these findings are generalizable to individuals from different populations. This is especially important given the increased risk of schizophrenia in ethnic minority populations.68 In addition, PRS were also derived differently across the studies. There were differences among the schizophrenia GWAS summary statistics (PGC2/PGC2 + CLOZUK4), genotyping arrays, standardization reference group, and method. Furthermore, it is likely that many of these studies did not have adequate power to detect what is likely to be a small effect.A considerable limitation of the literature is that all studies have been conducted in individuals of European ancestries. Currently, schizophrenia PRS is not as predictive of schizophrenia case-control status in non-European ancestries as the majority of the genetic studies are in individuals of European ancestries.69 and more contemporary PRS methods such as PRS-CS70 should be considered.Future research should include those from non-European ancestries, be conducted in larger clinical samples, incorporate rare genetic variation, and could consider including measures of childhood adversity from anonymized online data or using data linkage databanks. Researchers should also include measures of age, duration, type of adversity, and severity when investigating childhood adversity to explore other dimensions of the relationship between schizophrenia PRS and childhood adversity. Studies should also consider the inclusion of parental PRS to enable researchers to disentangle the nature of gene-environment correlation. Multiple PRS thresholds and power analyses should be used in future studies to demonstrate robust methodologiesWe have reviewed all studies investigating a gene-environment correlation and gene-environment interaction between schizophrenia PRS and reported childhood adversity. A multilevel meta-analysis demonstrates a small, yet significant gene-environment correlation between schizophrenia PRS and childhood adversity, indicating that a gene-environment correlation is likely to explain a minimal part of the association between childhood trauma and psychosis. The small effect size estimate is, however, dependant on the power of currently available PRS and more variance may be explained using other study designs and as GWAS become more powered. Due to the limited number of studies investigating gene-environment interaction, we were unable to conclude whether childhood adversity interacts with genetic predisposition to schizophrenia to increase the risk of psychosis. The methodological differences and limitations emphasize the need for further research, especially in clinical cohorts.sbac049_suppl_Supplementary_MaterialClick here for additional data file.


Cholelithiasis represents a known risk factor for digestive system neoplasm. Few studies reported the association between cholelithiasis and the risk of prostate cancer (PCa), and the results were controversial.We reviewed the medical records of the Second Affiliated Hospital of Chongqing Medical University Hospital to perform a retrospective matched case–control study, which included newly diagnosed 221 PCa patients and 219 matched controls. Logistic regression was applied to compare cholelithiasis exposure and adjusted for confounding factors. Additionally, we conducted a meta-analysis pooling this and published studies further to evaluate the association between cholelithiasis and PCa risk. Related ratio (RR) and 95% confidence interval (95%CI) were used to assess the strength of associations.Our case–control study showed that cholelithiasis was associated with a higher incidence of PCa  after multivariable adjustment for covariates. The incidence of PCa was increased in patients with gallstones but not cholecystectomy. 7 studies involving 80,403 individuals were included in the meta-analysis. Similarly, the results demonstrated that cholelithiasis was associated with an increased risk of PCa  with moderate-quality evidence. Cholelithiasis patients with low BMI increased the PCa incidence. Moreover, Subgroup analysis based on region showed that cholelithiasis was associated with PCa in Europe  and Asia .The results suggested an association between cholelithiasis and the risk of PCa. There was no significant relationship between cholecystectomy therapy and PCa risk. Further cohort studies should be conducted to demonstrate the results better. Worldwide more than 1,275,000 men are diagnosed annually with PCa. PCa is the second most common malignancy and the leading cause of cancer-associated mortality in men . EstabliWith the prevalence of about 5–15% of the western population, cholelithiasis was an important public health problem in Europe and America . CholeliThe relationship between the two diseases is still controversial. Given the potential risk factor of cholelithiasis in PCa, we assessed the relationship between PCa and cholelithiasis and conducted a hospital-based case–control study in the Second Affiliated Hospital of Chongqing Medical University Hospital, China. Furthermore, we performed a systematic meta-analysis of published studies and our case–control study to evaluate the association between cholelithiasis and the risk of PCa.This retrospective case–control was performed in the second affiliated hospital of Chongqing medical university study to investigate the association between cholelithiasis and PCa risk. Based on the confirmed pathological diagnosis record after performing a diagnostic biopsy or operation, 221 patients with newly diagnosed PCa were included in this study between 2018 and 2020. The patients with a history of malignancies or a family history of cancer were excluded. The 219 matched controls were randomly included from the patients admitted to the same hospitals. These controls were non-malignant neoplastic conditions unrelated to known risk factors for PCa. All the subjects were Chinese.According to subjects’ electronic medical records, we collected relative information, including a history of cholelithiasis, lifestyle habits , and comorbidity. The patients with a history of cholelithiasis were proven to provide the following information through subjects’ electronic medical records: abdominal ultrasound/ computed tomography, the presence of a relevant scar or having a clear medical record. If subjects with cholelithiasis were diagnosed more than 12 months before PCa diagnosis for cases or controls, we would consider them to have pre-existing cholelithiasis. Naturally, they would be excluded if they provided a date of the previous cholelithiasis no more than 12 months or lacked medical records. The ethics committee approved this study of the Second Affiliated Hospital of Chongqing Medical University following the ethical standards of the institutional and/or national research committee and with the 1964 Helsinki declaration. We did not require informed consent from the patients because we collected data by reviewing medical records.Following the PRISMA guidelines, the literature search of Medline, EMBASE, and Web of Science was conducted up to 1 November 2021. The following keywords or Medical Subject Heading (MeSH) terms related to PCa and cholelithiasis were used, including “Prostate Neoplasms, Prostate Neoplasm, Prostatic Neoplasm, Prostate cancer, Prostatic Cancer” and Risk factors and “Cholelithiasis, Gallstones or cholecystectomy.” There were no limitations on the language of studies to be included. The reference lists of the retrieved studies were manually searched for additional studies. Studies would be included if they met the following inclusion criteria: (a) these studies should be the associations of cholelithiasis with PCa risk; (b) these studies must be observational; (c) these studies provide risk estimates with 95% corresponding confidence intervals (CIs) were available. Reviews, case reports, and studies with overlapping or unavailable data were all excluded. All disagreements were resolved by discussion.Two authors (YDL and ZJR) independently extracted the following data from the included studies: author, publication date, country or region, study design, follow-up time, sample size, the number of PCa cases, risk estimates with corresponding 95% Cis, and adjusted factors. These data were extracted using a predefined data extraction sheet.Two independent authors used the Newcastle–Ottawa scale (NOS) to perform quality assessment of included studies. Each study had three aspects: selection of participants, study comparability, and outcome evaluation . The NOShttps://gradepro.org/), which assessed the aspects of risk of bias, inconsistency, indirectness, imprecision of the results, and publication bias. The evidence levels included very low, low, moderate, or high.The levels of evidence for outcomes were performed based on the GRADEpro approach  and its corresponding 95% confidence interval (CI) by performing unconditional logistic regression models with or without adjusting for age and lifestyle habits, and comorbidity. We further explored the association between cholecystectomy or gallstones and PCa risk. All data were analyzed using SPSS 17.0, and the P < 0.05 and I2 > 50% were regarded to be statistically significant for the between-study heterogeneity. Based on the between-study heterogeneity, we use a fixed or random effect model. Publication bias was evaluated by using funnel plots and Begg’s and Egger’s tests. All statistical analyses were performed using Stata statistical software . P value < 0.05 was considered to indicate statistical significance.For the meta-analysis, the association of cholelithiasis with PCa risk was measured by pooling the risk estimate. According to the study design, region, cholecystectomy, or gallstones, subgroup analyses of the primary outcomes were performed. The summary of effects for the outcomes was calculated as risk ratio (RR) and 95% confidence intervals (CI) using a random effect model. Both χ2-based Q test and I2 test were performed to estimate the between-study heterogeneity. P < 0.05).221 cases were newly diagnosed PCa, and 219 controls were recruited. Table Table The detailed process of the literature search was showed in Fig. 2 = 32.4%, P = 0.181) using a random effects model for assessment.A total of 7 studies, including our studies and 6 published studies, were eligible in this meta-analysis. As shown in Fig. To better evaluate the association between cholelithiasis and PCa risk. We conducted a subgroup analysis based on the study regions, BMI level, gallstones and cholecystectomy. The results of the subgroup analysis were shown in Table P = 0.545) and Egger’s test (P = 0.368) for PCa risk.We performed a sensitivity analysis to evaluate the risk of cholelithiasis on the overall estimate by removing individual studies, and we observed the stability of the results of this meta-analysis Fig. . Visual This study aimed to evaluate the impact of cholelithiasis on the subsequent PCa risk. In our case–control study, our findings from 221 cases and 219 controls provided evidence that men with pre-existing cholelithiasis had an increased risk of PCa, whereas we did not observe a significant association between cholecystectomy and PCa risk. Combined with the results of our meta-analysis, the history of cholelithiasis was significantly associated with PCa risk. However, as for cholecystectomy or gallstones, no significant risk difference was observed.Some previous studies have reported an association between a history of cholelithiasis and cardiovascular, cholangiocarcinoma and pancreatic cancer risk , 26, 27.A total of 7 studies were included in this meta-analysis. And we found that men with a history of cholelithiasis were associated with PCa risk. The increased PCa risk was also seen for both European and Asian population, as suggested by subgroup analysis according to a different region. In addition, the increased risk of PCa was observed for cholelithiasis patients with high and low BMI, as suggested by subgroup analysis according to different BMI. In the analysis of the different study designs, cholelithiasis was associated with the risk of PCa in case–control studies but not in cohort studies. The possible reasons for these disparities may be the limited number of included studies. In the future, we need better-designed studies to confirm this association.Cholecystectomy is mainly indicated for individuals with biliary tract infection and pancreatitis, and decreases the incidence of the biliary tract and pancreatic malignancy , 27. HowThe underlying mechanism of cholelithiasis might lead to malignancy development still deserves to be explored. The potential mechanisms for the association of cholelithiasis with PCa may be the following. Firstly, prostate cancer may be mediated by the cholesterol metabolism associated with cholelithiasis. Cholesterol was critical for the proliferation of cells, and its synthesis was tightly synchronized to cell cycle progression. Cholesterol-lowering may induce apoptosis in PCa cells progressing through the cell cycle , 29–32. There are some following strengths: to our knowledge, we firstly comprehensively estimated the association between cholelithiasis and PCa. We rigorously used the GRADE approach to assess the quality of evidence for the main findings. However, there are also several following limitations: firstly, with regard to meta-analysis, we include studies that adjusted or controlled for various risk factors, but some unknown or unmeasured residual confounders cannot be excluded. Secondly, in subgroup analysis, there are only two studies about cholecystectomy. We should be cautious about the results of.cholecystectomy. Last, the association between cholelithiasis and differ-grade PCa may be due to the limited current studies and well-designed studies are required to explore.In conclusion, our study supported the associations of cholelithiasis with the increased risk of PCa in European and Asian populations. There was no significant relationship between cholecystectomy therapy and PCa risk. Further cohort studies should be conducted to better identify more mechanisms in the pathogenesis of PCa.


Post-stroke depression (PSD) is a common neuropsychological complication after a stroke with a range of poor outcomes. Evidence of gut microbiota disorder for PSD has recently accumulated. This study aimed to systematically evaluate the association between PSD and gut microbiota.We searched PubMed, Web of Science, Embase, and VIP, CNKI, Wangfang without language restrictions for eligible studies and performed a meta-analysis and systematic review to assess the pooled differences in gut microbiota compositions between PSD and healthy individuals.Proteobacteria , Bacteroidetes , and Fusobacteria  in patients with PSD significantly was increased as compared to controls, while the pooled relative abundance of Firmicutes  was significantly decreased in PSD as compared to healthy controls. Moreover, significant differences in intestinal microbiota were observed between PSD patients and healthy controls at the family and genus levels.We included nine eligible studies reporting the differences in the intestinal microbiome between PSD and healthy control. The pooled results demonstrated that the sequencing depth index (Good's coverage), richness indexes (Chao1 and ACE), evenness, and alpha diversity (Shannon and Simpson) were not significantly changed in PSD patients as compared to healthy controls. The observed species  in PSD was significantly higher than that in healthy individuals . Furthermore, we observed significant differences between PSD and healthy individuals at the phylum level. The pooled estimation of relative abundance of This meta-analysis indicates a significant alteration of observed species and microbiota composition at the phylum, family and genus levels in PSD as compared to healthy individuals. Post-stroke depression; Gut microbiota; Meta-analysis; Alpha diversity; Phylum. Post-stroke depression (PSD) is a frequent and burdensome neuropsychological complication after a stroke, which often presents with poor outcomes and high mortality rates . The preThe intestinal microbiome is the major microbial community that settles in the human body and substantial evidence suggested the crucial role of the intestinal microbiome in stroke onset. Trimethylamine N-oxide (TMAO) is a waste product of gut microbes and was associated with the development of stroke . A recenIn this study, we conducted a meta-analysis of all available studies comparing the gut microbiota in PSD and healthy control. The eligible studies were enrolled from six public databases without language restriction, and relevant data were extracted directly or indirectly from the articles. Finally, we evaluated the pooled differences in intestinal microbiome compositions between PSD patients and controls.22.1For eligible studies collection, we systematically and comprehensively searched in PubMed, Web of Science, Embase, Cochrane databases, Wangfang, VIP, and CNKI up to July 2022 using the following search keywords: “stroke” and “depression” and  and (“microbiota” or “microbiome” or “microorganisms”) without language restriction. This meta-analysis was conducted on the basis of the Preferred Reporting Items for Systematic Reviews and Meta-analyses (PRISMA) criteria.2.2Eligible studies were identified according to the following criteria: 1) comparing the gut microbiota in PSD and healthy controls; 2) providing sufficient data for pooled differences analysis; 3) providing available full text. The exclusion criteria were as follows: review, animal studies, and conference abstract.2.3The following information for each eligible study includes the first authors’ name, date of publication, country, sample size, detection method, richness and diversity indexes of 16S rRNA-sequencing data, and relative abundance of gut microbiota. Two researchers independently extracted and assessed the data, and any disagreements were resolved by consensus between the reviewers. The methodological quality of included articles was assessed by the selection, comparability, and outcome information of each study according to the Cochrane Non-Randomized Studies Methods Group recommendations .2.4I2 statistic, and a fixed-effect model was used when I2 > 50%, otherwise, the random-effect model was applied.All statistical analysis was performed using the STATA SE 15 software. The average and 95%CI of the sequencing depth index (Good's coverage), richness indexes , and the relative abundance of gut microbiota were extracted and calculated. We evaluate the differences in gut microbiota compositions using the standardized mean differences (SMD) between the PSD and healthy controls, while a positive SMD indicates a higher level in PSD patients than in healthy controls. Conversely, a negative SMD indicates a lower level in PSD patients. The heterogeneity among included research was examined using the 33.1The flow chart of the literature search and selection progress was shown in 3.2To evaluate the pooled differences in general characteristics of high throughout-sequencing between PSD and healthy individuals, we first performed a meta-analysis on multiple relevant indexes, including the sequencing depth (Good's coverage), richness , evenness, and alpha diversity (Shannon and Simpson). Seven studies provided available data on general characteristics and were included in the quantitative analysis. The detail information on the meta-analysis were shown in I2 = 89%). The observed species/OTU were reported 3 articles (164 PSD vs 158 controls), and the pooled analysis revealed a significantly higher observed species/OTU in PSD vs controls  and a high heterogeneity (I2 = 52.5%) among studies. Five studies provided data on Chao1 in PSD (n = 209) and controls (n = 180). The pooled estimate demonstrated an insignificant difference between PSD and controls . Meanwhile, six studies with 235 PSD and 210 healthy controls reported ACE data, and the results found no significant difference between PSD and healthy individuals . Regarding diversity, six studies provided the Shannon index in 264 PSD patients and 233 controls. Owing to the high heterogeneity (I2 = 97.5), the pooled effects were evaluated using a random-effect model and showed an insignificant difference between PSD and controls . Similarly, the pooled effects of the Simpson index from six studies were also assessed using a random-effects model, with no significant difference observed . Finally, three studies with 164 PSD and 158 controls provided sufficient data for the pooled estimate of evenness, which also revealed an insignificant SMD in evenness between groups (p = 0.434). Stratification analysis was performed according to limited data of region, male/female ratio (MFR), and average value of age. It was found that age had a significant impact on ACE and Chao I.Four studies reported the Good's coverage index of 16S rRNA-sequencing results in PSD (n = 190) and healthy persons (n = 188). The results revealed an insignificant pooled estimation of Good's coverage index between patients and controls  under the random-effect model due to high heterogeneity  as compared to controls  and Fusobacteria    . Meanwhi3.4Bacteroidaceae, Lachnospiraceae, Erysipelotrichaceae, Prevotellaceae, and Ruminococcaceae. Meanwhile, the intestinal contents of the other 4 families  in PSD patients were significantly elevated as compared to the healthy controls. At the genus level, the meta-analysis showed that two genera including Prevotella and Ruminococcus presented with a lower intestinal content in the intestine of PSD patients. Meanwhile, PSD patients had a significantly higher content of four genera, including Faecalibacterium, Escherichia-Shigella, Megamonas, and Bacillus, as compared to the healthy controls. Insignificant differences in the intestinal content of Roseburia and Blautia were not observed between the PSD patients and healthy controls.In order to more comprehensively and clearly describe the characteristics of the intestinal flora of PSD patients, we further conducted a meta-analysis at the family and generic levels. 4Post-stroke depression is a common complication after a stroke. In addition to limb dysfunction, the clinical manifestations of patients are also accompanied by mental and emotional abnormalities, such as low mood, decreased interest in external things, and delayed thinking functions. These symptoms seriously reduce the compliance with medical activities of stroke survivors, which is not conducive to the recovery of limb function . StudiesFirmicutes were found to be dramatically lower in PSD versus controls, while the other three phyla  were revealed to be significantly lower in PSD versus controls.In the present study, we conducted a meta-analysis and systematic review to assess gut microbiota perturbations in patients with PSD for the first time. The results revealed a discrepant abundance of intestinal bacterial phyla in PSD versus healthy individuals across the studies. However, no significant differences in the majority of richness and diversity indexes, except for observed species. PSD patients were observed with a higher observed species as compared to controls in a third of the studies. The differences in the abundance of the four major gut-dominant phyla are mainly as follows: Enterococcus faecalis, Bifidobacterium, Escherichia coli, using the ATB expression identification system [Enterococcus faecalis and Escherichia coli, as well as a significantly lower abundance of Bifidobacterium in PSD as compared to healthy controls. Despite unavailable data on these gut microbiota compositions in other high-throughout sequencing research, current studies may also suggest a possibly important role for these gut microbiota compositions in PSD patients. Enterococcus faecalis is a ubiquitous gram-positive bacterium common in the digestive tract and an important opportunistic pathogen [Escherichia coli is a conditional pathogen that is commonly found in the intestines of humans and is associated with a variety of gastrointestinal infections [Bifidobacterium have been indicated as a biomarker for health because Bifidobacterium confers a large range of health benefits to the metabolic and immune system. Antidepressant therapy targeting intestinal Bifidobacterium has also been developed [Eight of the included studies investigated the gut microbiota using 16S rRNA-sequencing technology , 25, 26,pathogen . In addifections . The preeveloped . In addieveloped .Bacteroidetes in PSD was significantly higher than that in controls [Firmicutes in PSD than in controls. Despite insufficient data for the evaluation of the Firmicutes/Bacteroidetes ratio, we could infer its downtrend in the PSD based on the opposite trend of Firmicutes and Bacteroidetes in the PSD. The Firmicutes and Bacteroidetes are two kinds of predominant beneficial bacteria in the human gut with a stable ratio in healthy adults, whereas its disorder was closely related to obesity and diabetes [Firmicutes/Bacteroidetes ratio in mice [Proteobacteria is the second largest group of bacteria, comprising several known human pathogens such as Brucella and Rickettsia. Accumulating evidence identified Proteobacteria as a possible signature of diseases, such as irritable bowel syndrome [Proteobacteria in PSD as compared to healthy controls. The existing hypothesis proposed that Proteobacteria bloom was associated with increased availability of oxygen resulting from the reduced beta-oxidative capacity of epithelial cells under stroke-induced intestinal inflammation [Fusobacteria, a small group of Gram-negative bacteria, was found to be significantly increased in PSD as compared to healthy individuals in this meta-analysis.Six of eight studies conducting 16S rRNA-sequencing provided sufficient data for the pooled estimation of gut microbiota composition at the phylum level , 25, 26.controls , 24, 26,controls . Meanwhidiabetes , 42. Zha in mice . Proteobsyndrome  and autosyndrome . The metammation . MoreoveAcidaminococcaceae was positively correlated with self-reported depression [Acidaminococcaceae in PSD patients. In addition, we also observed significantly elevated content in the other three families and reduced content in five families. Three families including Bacteroidaceae, Fusobacteriaceae, and Prevotellaceae presented with the same change pattern in PSD and depression, suggesting their potential role in the occurrence and development of depression. Other families without similar change patterns may be closely related to stroke. For example, the modulation of Lachnospiraceae and Ruminococcaceae was suggested to contribute to the therapeutic effects of the combination of Puerariae Lobatae Radix and Chuanxiong Rhizoma on cerebral ischemic stroke [Escherichia-Shigella and Faecalibacterium, was responsible for the stroke-induced gut microbial disturbances [Further investigation revealed the dysregulation of various intestinal microbiota at the family and genus levels. Recently, it was reported that the intestinal content of pression . Consistc stroke . Meanwhiurbances . These d4.1There are several limitations in this meta-analysis. Firstly, the sample size of included studies is small, which might make the results less robust. Secondly, part of the analysis data was indirectly extracted from the article, which may deviate from the real data. Finally, due to the unavailable high-throughout sequencing data, we failed to conduct an individual-based meta-analysis using a standardized bioinformatic pipeline that could help to clarify the discrepant findings.5In the present study, we revealed discrepant distribution in the intestinal flora of PSD patients versus healthy controls at the phylum, family and genus levels. Higher observed species in PSD versus controls were observed, whereas the Good's coverage, Chao1, ACE, evenness, and alpha diversity indexes yielded no significant differences. However, these findings are not sufficient to generalize to a larger population given the small number of studies and sample size as well as substantial heterogeneity. Further high-quality studies are required to validate these findings. Meanwhile, an individual-level meta-analysis with standardized analysis pipelines should be developed and adopted to exclude the differences in the generation and processing of 16S rRNA-sequencing data.Fang Luo and Chengbing Fang: Conceived and designed the experiments; Performed the experiments; Analyzed and interpreted the data; Contributed reagents, materials, analysis tools or data; Wrote the paper.This research did not receive any specific grant from funding agencies in the public, commercial, or not-for-profit sectors.Data will be made available on request.The authors declare no competing interests.No additional information is available for this paper.


In recent years, a growing number of researches indicate that S100B may act in migraine, but the relationship between S100B and migraine remains controversial. Therefore, the current study aimed to perform a meta-analysis to quantitatively summarize S100B levels in migraine patients.We used Stata 12.0 software to summarize eligible studies from PubMed, EMBASE, Web of Science, Cochrane Library, China National Knowledge Infrastructure (CNKI), and Wanfang databases. We applied standardized mean differences (SMDs) with 95% confidence intervals (95%CIs) to appraise the association between S100B and migraine.P < 0.001). The S100B levels in migraineurs during ictal periods  and interictal periods , aura  and without aura  were significantly higher than those in the controls. The subgroup analyses by age, country, migraine assessment, and assay method of S100B also illustrated a statistically obvious association between S100B levels and migraine, indicating that age may be the most important source of heterogeneity. Sensitivity analysis showed that no individual study has a significant influence on the overall association between S100B and migraine.The combined results of nine case-control studies indicated that compared with healthy controls, overall migraine patients had significantly increased S100B levels in peripheral blood (SMD = 0.688, 95%CI: 0.341–1.036, This meta-analysis demonstrates that the level of S100B in peripheral blood of patients with migraine was significantly increased. Migraine may be associated with pathological reactions involving S100B, which is instrumental for the clinical diagnosis of migraine and therapy that considers S100B as a potential target. Migraine has been known as a leading cause of disability worldwide through the ongoing Global Burden of Diseases, Injuries, and Risk Factors Study , 2, withThe S100 protein family comprises 24 calcium-binding proteins that exert intracellular or extracellular regulatory effects. They act as calcium-activated switches and regulate the activity of various targets in different tissues. S100B is mainly serried in astrocytes  and otheThe mechanism of migraine is not fully understood, and the release of many inflammatory factors involves the entire process and its chronicity. Calcitonin gene-related peptide (CGRP) levels increase during ictal periods of migraine, and experiments have shown that it originates from stimulating trigeminal nerve fibers , leadingThis meta-analysis was conducted in terms of the guidelines of the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) .A comprehensive search was executed in the PubMed, Web of Science, EMBASE, Cochrane Library, China National Knowledge Infrastructure (CNKI), and Wanfang databases by two independent investigators (CC and RZ) from inception to October 2021, with no restrictions on population. Languages are limited to English and Chinese. We used the following combination of subject headings and free terms:  and (migraine disorders OR migraine OR hemicrania OR headache). Detailed search term strategies are presented in the All potential studies were reviewed step-by-step by two researchers (CC and RZ) independently . IrrelevInformation was extracted on the first author, publication year, country, age, gender distribution , sample size, diagnosis, and study design . When thThe quality of the included study was estimated by using the Newcastle-Ottawa Scale. This score classifies individual studies across three domains: selection, comparability, and exposure. Two researchers independently estimated the quality of the studies and resolved any disagreements through discussion.P-values < 0.05, were regarded as statistically significant. Substantial heterogeneity of the included studies was confirmed by >50% and P-value of Q test < 0.10). A random-effects model or a fixed-effects model was selected by I2-value. Sensitivity analyses were performed to examine the potential source of heterogeneity using leave-one-out cross-validation. Begg's rank correlation test and Egger's regression asymmetry test were employed to evaluate publication bias if the number of included studies was >8 in the meta-analysis. Stata  was used for the statistical analysis.Associations between S100B levels and migraine was assessed by using SMDs with 95%CIs describing continuous data, and the results are visualized as forest plots, which included the contribution of each study (weight) to the overall effect. In the present meta-analysis, results with two-tailed The systematic literature search produced 322 references. In total, 103 duplicate references were removed first. We identified 13 studies that were potentially eligible for inclusion after scanning the titles and abstracts. After the full-text assessment, nine studies were evaluated for eligibility and included in the quantitative analysis . A flowcNine included studies comprising 633 individuals (369 migraine cases and 264 controls) were published between 2005 and 2021. Two of the studies were conducted in China and seven in Europe.The Newcastle-Ottawa Scale scores of the studies varied from 6 to 8 points (mean score: 6.81), implying the good quality of the included studies. Specific quality scores of the included studies are listed in I2 = 77.0%, P < 0.001). Synthetic results illustrated that overall migraine patients  had significantly elevated S100B levels in peripheral blood compared to healthy controls   .Of the nine studies included in the meta-analysis, eight studies contained S100B levels of migraineurs in the interictal period and five studies in the ictal period.I2 = 18.0%, P = 0.288) indicated that S100B levels were significantly higher in interictal patients than in controls  (P = 0.002), the corresponding I2-statistic was 86.6% (P < 0.001) .The combined results of the meta-analysis  . Similar< 0.001) . The S10P < 0.001), the corresponding I2-statistic was 0.0% (P = 0.412)  . The S100B levels were not significantly difference in patients without aura than with aura .S100B levels were significantly higher in migraineurs without aura than in controls in the meta-analysis pooling four studies  . S100B l= 0.790) . MigrainP = 0.089), the corresponding I2-statistic was 68.1% (P = 0.076). S100B levels were also not significantly difference in patients with episodic migraine than in controls .S100B levels were not significantly difference in patients with chronic migraine than in controls in the meta-analysis pooling two studies  than in adults  and other age groups  . The heterogeneity decreased notably after the age subgroup analysis, which indicated that age or only one study on children may be an important source of heterogeneity. In addition, the results of stratification by country, diagnosis of migraine, and assay method of S100B indicated a correlation between elevated S100B and migraine . The I2 Sensitivity analysis (including a minimum of three studies) was performed to assess and evaluate the stability and reliability of the overall SMD by leave-one-out cross-validation, which repeated the analysis after the sequential exclusion of each study. The results were not substantially altered after the serial exclusion of individual studies . Thus, tP > |z| = 0.754) and Egger linear regression (P = 0.220) were only used to roughly evaluate publication bias. Positive results may be more likely to be published, which may lead to publication bias in this study.Since the number of studies we included was <10, the results of the Begg rank correlation test  and calcium (Ca2+) and exists in the nucleus and cytoplasm of a broad range of cells  are modulated by extracellular S100B protein in astrocyte cultures, resulting in increased activation of phosphorylation products . ERK andIn some neurological diseases, some measures also play a role in ameliorating diseases and reducing the expression of S100B at the same time. S100B knockout mice showed reduced Aβ plaque formation in the cortical region in an experimental Alzheimer's disease model . In addiThis study has strengths and limitations. Its strengths lie in this is the first meta-analysis on this topic, and we investigated the relationship between various types of migraine and the level of S100B. These may contribute to the study of the pathological mechanism of migraine.There are also some limitations in the present study that cannot be neglected. The present research may be biased due to the inability to obtain unpublished literature and the inclusion of only Chinese and English literature. Although this is the first meta-analysis on this topic, the quality of the research results may be affected by the scarcity of related studies and the small sample size of the included studies. Large-scale studies are needed to provide more deterministic evidence. Although we have found an important source of the overall heterogeneity through age subgroups, there was only one article in the children subgroup, and more studies in this age group are needed in the future to confirm the relationship between S100B and child migraine. Due to the lack of more detailed characteristics of migraine, such as the disease duration and frequency of attacks in the included studies, our research was not been able to further explore the changes of S100B in migraines of different severity, which requires further research.In summary, this study provides evidence that S100B levels were significantly increased in migraine patients compared to controls, and helps to understand the pathological mechanism of migraine and the possible implementation of S100B-targeted therapies for migraine.The original contributions presented in the study are included in the article/WL guided the design of the study and revised the manuscript. CC designed the study, screened the literature, extracted data, performed the statistical analysis, and wrote the manuscript. RZ and MC supported the screening of literatures and extracted data. NL supported the visualization of the results. All authors contributed to the article and approved the submitted version.The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest.All claims expressed in this article are solely those of the authors and do not necessarily represent those of their affiliated organizations, or those of the publisher, the editors and the reviewers. Any product that may be evaluated in this article, or claim that may be made by its manufacturer, is not guaranteed or endorsed by the publisher.


We read with interest this review by Ramai et al. , who comFirst some background for context: It is well known that patients with two different types of porphyria, acute intermittent porphyria (AIP) and porphyria cutanea tarda (PCT) have an increased risk of primary liver cancer (PLC), mainly HCC. PCT, the most common type of porphyria, is in most patients an acquired enzyme deficiency caused by underlying liver diseases such as hepatitis C or alcohol-related liver disease. A minority have an inherited enzyme deficiency that causes a disease with similar clinical manifestations. AIP, variegate porphyria (VP), and hereditary coproporphyria (HCP) are commonly grouped together as acute hepatic porphyrias (AHP) due to similar clinical and biochemical features. The AHP are inherited monogenic diseases with low penetrance that affect different enzymes in the heme synthesis pathway and potentially lead to the accumulation of the heme precursors delta-aminolaevulinic acid (ALA) and porphobilinogen (PBG).AHP and PCT are completely different diseases, and the carcinogenic pathways differ significantly. While patients with PCT have an underlying liver disease that may lead to an increased risk of cirrhosis and PLC, AHP patients rarely have significant liver fibrosis. Most AHP-associated PLCs are diagnosed in non-cirrhotic livers and the current understanding is that the carcinogenesis pathway is related to the intrahepatic accumulation of ALA ,3,4. SevWe have several comments on the contents of the review.To start with, the authors chose to include studies on both PCT and AHP in this review: 10 studies include only AHP, 7 only PCT, and 2 studies include both AHP and PCT patients. If doing so, the cohorts must be assessed, analyzed, and discussed separately. To combine cohorts with AHP and PCT, and to only present the common risk estimate is comparable to combining patients with, for instance, viral and autoimmune hepatitis, two diseases with fundamentally different pathogenesis, and only presenting the combined risk estimate.In the first statement of the discussion, the authors state that “patients with AHP had an estimated 5% risk of primary liver cancer”. This is incorrect, since the 5% risk estimate reflects the combined risk of the AHP and PCT cohorts. The risk in AHP is not assessed in this review.In the final paragraph of the discussion, the authors write that “This study provides further evidence to the current understanding of HCC in patients with AHP. This extensive review includes 19 studies from multiple countries, supporting screening guidelines in this patient population”. Again, only the term AHP is used. Only 12 of those 19 studies included patients with AHP, which makes the reference to AHP incorrect. Furthermore, PCT, the porphyria type included in nine of the studies, is not mentioned at all in the discussion. It is unclear whether the authors included the PCT studies erroneously as AHP, or if those studies were in fact not included in the final conclusions.It is hard to follow which patient group that the authors refer to in different parts of this review. The vague term “porphyria” is used alternately with the more precise AHP in an imprecise and, in some instances, erroneous way. Two examples:Neither age nor disease severity are included in the analysis or the discussion, in this study, which makes the risk assessment less accurate. Cohorts included in this review vary significantly in terms of demographics and clinical disease severity. Age is a significant risk factor for the development of HCC . As an eThe main aim of this review was to assess the PLC risk in “porphyria”. Including both PCT and AHP is, as mentioned above, of doubtful relevance. The results nevertheless deserve a thorough examination. The stated 4.8% risk of PLC in “porphyria” was calculated by dividing the total number of patients with PLC (351) by the total number of patients at risk (7381). That estimation is based on incorrect calculations.Starting with the numerator, there are significant errors. The authors included 102 cases of PLC from the study by Hardell et al. from 1984 . This caWe also object to the authors’ approach to the issue of overlapping studies. In the methods, the authors state that “In the event of multiple publications from the same cohort or overlapping cohorts, data from the most recent and/or most appropriate comprehensive report were retained.” This is an important principle that was unfortunately not followed throughout this review.The important study by Baravelli et al. from 2017  on PLC rMany of the studies from Sweden have significant overlap but none were excluded. For example: Lithner 1984  overlapsn = 7381), patients at risk, we again find several significant errors:The 103 cases in the Hardell study  are consAccording to Table 1 in the review  are inclThe authors state that the porphyria cohort size in the study by Andersson 1996  was 2122Concerning the Innala 2011 study , the staConcerning the Lang 2015 study [Continuing with the denominator  is of interest as a possible tool in HCC surveillance. The EASL guidelines  do not rFinally, in the results (Table 2) and in the discussion, the authors state that 56  liver transplantations were performed with PLC as an indication, referring to Elder et al. . This isA list of additional comments regarding this review are presented in Considering the lack of fact-checking, the amount of inaccurate data included in the analyses, and the poor understanding of the different disease entities included in this review, we suggest a thorough revision of this paper. We strongly recommend including researchers with porphyria experience in the revision process, and to invite reviewers with such expertise to ensure a rigorous peer-review process. In its present form, this review by Ramai et al. misleads the readership.


Allergic diseases are type I hypersensitivity reactions mediated by various allergens. The most common allergic diseases include allergic rhinitis, allergic asthma, allergic dermatitis, and allergic conjunctivitis. The incidence of allergic diseases has been increasing in the recent past, and allergen avoidance and adoption of desensitization treatment can significantly decrease the incidence of allergic diseases. Previous studies have explored the association between vitamin A supplementation and allergic diseases; however, the results are inconsistency. The aim of the present study was to evaluate the association between vitamin A supplementation and allergic diseases, with a focus on atopy and wheezing.Articles reporting randomized controlled trials (RCTs) on the association of vitamin A supplementation and allergic diseases were retrieved from PubMed, Embase, Web of science, and China National Knowledge Infrastructure database from inception of to November 15, 2021. STATA 12.0 software was used for meta-analysis, sensitivity analysis and analysis of publication bias.P = 0.171, I2 = 43.4% fixed effect model]. The frequency of delayed atopy among adults was associated with vitamin A supplementation . Analysis showed no significant association between vitamin A supplementation with incidence of wheezing in children . Sensitivity and publication bias analysis showed that each individual study did not affect the combined results and there was no significant publication bias among the studies.Seven studies comprising 2201 participants met the inclusion criteria and were included in the meta-analysis. The findings showed that vitamin A supplementation was associated with increased risk of atopy in young females compared with the placebo [RR = 1.70, 95% confidence interval , The findings showed that vitamin A supplementation is associated with increased risk of atopy but no correlation was observed with the incidence of wheezing. The results of this meta-analysis provide evidence for effective management of fibrosis. More studies should be conducted to verify the results. Allergic diseases are type I hypersensitivity reactions mediated by various allergens. Allergic rhinitis, allergic asthma, allergic dermatitis, and allergic conjunctivitis are the most common allergic diseases. Allergens can be divided into two categories: perennial allergens, and seasonal allergens. Perennial allergens mainly include dust mites, mold, cockroaches, and other indoor allergens whereas seasonal allergens include pollen and other outdoor allergens. The incidence of allergic diseases has been increasing in recent years and these diseases markedly affects the quality of life of patients.Allergen detection is an important step in diagnosis of allergic diseases. The allergen avoidance method and desensitization treatment are effective in treatment of allergic diseases. Conventional methods used for treatment of allergic diseases include use of allergy medications and hormones, which have adverse effects. Bronchial asthma (asthma for short) is a common chronic disease that affects children aged 5–14 years worldwide , 3. The Vitamin A deficiency (VAD) is a worldwide nutritional and public health concern . StudiesStudies have been conducted to explore the effect of vitamin A on allergic diseases, but the results are not conclusive. Therefore, the presented study was conducted to evaluate the association between vitamin A and incidence of allergic diseases.Randomized controlled trials published in PubMed, Web of Science, Embase, and China National Knowledge Infrastructure databases from inception of the database to Nov 15, 2021 were retrieved using the following search terms: (1) Vitamin A; (2) allergy; (3) wheeze; (4) atopy; (5) allergic diseases; (6) allergic; (7) immune; (8) supplement; (9) supplementation. The search strategy comprised medical subject headings (mesh) and text words joined by the Boolean operator “and.” This meta-analysis was registered in INPLASY platform (202240032). The methodology is referred to previous publications –16.A comprehensive search was conducted in the databases without restrictions on language or publication status. The search was restricted to studies comprising human participants. Articles from the bibliographies of retrieved articles were included to find other relevant studies not found through the search strategy.A comprehensive review of the retrieved articles was conducted to ensure that they met the following inclusion criteria: (1) study design was double-blind, randomized, placebo-controlled trials; (2) the intervention was vitamin A or placebo; (3) the outcome was allergic diseases, including atopy, wheezing, etc.; (4) the full text was available for reference.The exclusion criteria in this study were: (1) studies on other non-human subjects; (2) studies that compared other interventions; (3) studies that had insufficient data; (4) comments, abstracts, reproduction of publications.Two reviewers (JQS and TL) independently reviewed detailed information including the titles, abstracts, and full-text articles of the retrieved studies. Any differences between the two reviewers were resolved through discussion with a third reviewer (HP). The following data parameters were extracted from the studies: name of main author, publication year, country, participants, number of participants in each group, characteristics of intervention, and outcome. The JADAD scale was used to evaluate the methodological quality of the selected randomized controlled trials. The JADAD scale comprised three items with a score of 0–5 points as follows: (1) generation method of the random grouping sequence (0–2 points); (2) Double-blind method: the specific protocol of double-blind implementation was described and considered appropriate (0–2 points); (3) Withdrawal and loss of subjects to follow-up: the number of cases that withdrew from the study and loss to follow-up and reasons for withdrawal were described in detail (0–1 point). Egger’s test and funnel plot was generated assess the publication bias in included studies.I2 statistics: values of 0–25% represented low heterogeneity, 26–75% moderate heterogeneity, and values greater than 75% indicated significant heterogeneity. Data were considered highly heterogeneous if the chi-squared test presented a P-value < 0.10 and I2 > 50%. The random effect model was used for analysis of studies if P < 0.05 or I2 > 50%, otherwise the fixed effect model was used to conduct the analysis. The funnel plot was visually analyzed to assess publication bias. Sensitivity analysis was conducted to explore the potential sources of heterogeneity. Sensitivity analysis was performed by deleting one study at a time to evaluate the impact of individual results on the overall analysis. All statistical analyses were conducted using STATA software version 12.0. All statistical analyses were two tailed, and P < 0.05 indicated statistical significance.Heterogeneity of included studies was determined by chi-squared test and A total of 312 articles were retrieved from PubMed, EMBASE, web of science and CNKI databases through the initial search. Subsequently, 113 articles were retained after the first screening. An additional 88 records were excluded after reviewing the titles and abstracts of retrieved articles since they were review articles, case reports, letters, comments, or editorials, resulting in 25 eligible articles. A total of 18 articles were further excluded for various reasons, including different research designs or insufficient data. Finally, 7 studies comprising 2,201 participants met the inclusion criteria and were included in this meta-analysis –23. PRISThe main characteristics of the eight studies included in this review are presented in P = 0.090, I2 = 58.6% random effect model) , t model) . Furthert model] . The resP = 0.018, I2 = 82.1% random effect model] , t model] .Jadad assessment tool was used to evaluate the methodological quality of included studies. All 7 articles were evaluated from three aspects: “random grouping sequence generation method,” “allocation hiding” and “blinding method.” The results showed that the 7 articles were of high quality .Sensitivity analysis showed that exclusion of one study at a time did not alter significantly the combined risk ratio (RR) –3. VisuaIn this study, the findings showed that the incidence of rapid atopy among young female participants in the vitamin A supplementation group was higher than that of the control group. In addition, the frequency of delayed atopy in the experimental group was higher than that of the control group. However, the incidence of wheezing in the experimental group was not markedly different from that of the control group. The results of our study have important clinical significance since they indicated that reasonable supplementation of vitamin A is important for both children and adults.The findings did not show any association between vitamin A supplementation and wheezing. However, some previous studies reported an association between vitamin A and wheezing. For instance, previous findings indicated that a low dose of vitamin A supplementation in early life is a protective factor for skin and respiratory allergic diseases , 25. MorThe mechanism of the risk of atopy caused by higher doses of vitamin A supplementation has not been fully elucidated. Schuster et al. reported that large doses of VAS can inhibit Th1 function, promote Th2 cytokine expression, and upregulate expression of IL4, IL5, IgE and eosinophils, but aggravate immune disorders . This fiThe present meta-analysis had some limitations. First, baseline data were inconsistent across some articles. Second, retrieval of studies published in only one language, different dosages, varying dosage forms and different study regions where vitamin A supplementation was conducted may lead to biased results. Third, only seven studies were included in this meta-analysis and the results should be further verified by including more studies conducted using different populations.In summary, the findings of this meta-analysis indicate that vitamin A supplementation may increase the incidence of rapid atopy and increase the frequency of delayed atopy. The results provide practical and valuable insights for vitamin A supplementation. Additional prospective large-scale studies conducted in more countries/populations should be analyzed to elucidate the underlying mechanisms underlying the effect of vitamin A supplementation and atopy.The original contributions presented in this study are included in the article/JS drafted the manuscript, generated the figures for manuscript, and conducted literature review. TL performed literature review and revised the final manuscript. HP provided supervision and contributed to the conceptualization of the review. All authors read and approved the final version of the manuscript for publication.