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Gastroenterology Sep 2019Multiple environmental factors have been associated with the development of inflammatory bowel diseases (IBDs). We performed an umbrella review of meta-analyses to... (Meta-Analysis)
Meta-Analysis
BACKGROUND & AIMS
Multiple environmental factors have been associated with the development of inflammatory bowel diseases (IBDs). We performed an umbrella review of meta-analyses to summarize available epidemiologic evidence and assess its credibility.
METHODS
We systematically identified and appraised meta-analyses of observational studies examining environmental factors and risk of IBD (Crohn's disease [CD] or ulcerative colitis [UC]). For each meta-analysis, we considered the random effects estimate, its 95% confidence interval, the estimates of heterogeneity, and small-study effects, and we graded the evidence according to prespecified criteria. Methodologic quality was assessed with AMSTAR (ie, A Measurement Tool to Assess Systematic Reviews) 2.
RESULTS
We examined 183 estimates in 53 meta-analyses of 71 environmental factors related to lifestyles and hygiene, surgeries, drug exposures, diet, microorganisms, and vaccinations. We identified 9 factors that increase risk of IBD: smoking (CD), urban living (CD and IBD), appendectomy (CD), tonsillectomy (CD), antibiotic exposure (IBD), oral contraceptive use (IBD), consumption of soft drinks (UC), vitamin D deficiency (IBD), and non-Helicobacter pylori-like enterohepatic Helicobacter species (IBD). We identified 7 factors that reduce risk of IBD: physical activity (CD), breastfeeding (IBD), bed sharing (CD), tea consumption (UC), high levels of folate (IBD), high levels of vitamin D (CD), and H pylori infection (CD, UC, and IBD). Epidemiologic evidence for all of these associations was of high to moderate strength; we identified another 11 factors associated with increased risk and 16 factors associated with reduced risk with weak credibility. Methodologic quality varied considerably among meta-analyses. Several associations were based on findings from retrospective studies, so it is not possible to determine if these are effects of IBD or the results of recall bias.
CONCLUSIONS
In an umbrella review of meta-analyses, we found varying levels of evidence for associations of different environmental factors with risk of IBD. High-quality prospective studies with analyses of samples from patients with recent diagnoses of IBD are needed to determine whether these factors cause or are results of IBD and their pathogenic mechanisms.
Topics: Colitis, Ulcerative; Crohn Disease; Drug-Related Side Effects and Adverse Reactions; Environment; Environmental Exposure; Humans; Hygiene; Life Style; Protective Factors; Risk Assessment; Risk Factors; Surgical Procedures, Operative; Vaccination
PubMed: 31014995
DOI: 10.1053/j.gastro.2019.04.016 -
The Lancet. Psychiatry Nov 2020Many potential environmental risk factors, environmental protective factors, and peripheral biomarkers for ADHD have been investigated, but the consistency and magnitude... (Meta-Analysis)
Meta-Analysis
BACKGROUND
Many potential environmental risk factors, environmental protective factors, and peripheral biomarkers for ADHD have been investigated, but the consistency and magnitude of their effects are unclear. We aimed to systematically appraise the published evidence of association between potential risk factors, protective factors, or peripheral biomarkers, and ADHD.
METHODS
In this umbrella review of meta-analyses, we searched PubMed including MEDLINE, Embase, and the Cochrane Database of Systematic Reviews, from database inception to Oct 31, 2019, and screened the references of relevant articles. We included systematic reviews that provided meta-analyses of observational studies that examined associations of potential environmental risk factors, environmental protective factors, or peripheral biomarkers with diagnosis of ADHD. We included meta-analyses that used categorical ADHD diagnosis criteria according to DSM, hyperkinetic disorder according to ICD, or criteria that were less rigorous than DSM or ICD, such as self-report. We excluded articles that did not examine environmental risk factors, environmental protective factors, or peripheral biomarkers of ADHD; articles that did not include a meta-analysis; and articles that did not present enough data for re-analysis. We excluded non-human studies, primary studies, genetic studies, and conference abstracts. We calculated summary effect estimates (odds ratio [OR], relative risk [RR], weighted mean difference [WMD], Cohen's d, and Hedges' g), 95% CI, heterogeneity I statistic, 95% prediction interval, small study effects, and excess significance biases. We did analyses under credibility ceilings, and assessed the quality of the meta-analyses with AMSTAR 2 (A Measurement Tool to Assess Systematic Reviews 2). This study is registered with PROSPERO, number CRD42019145032.
FINDINGS
We identified 1839 articles, of which 35 were eligible for inclusion. These 35 articles yielded 63 meta-analyses encompassing 40 environmental risk factors and environmental protective factors (median cases 16 850, median population 91 954) and 23 peripheral biomarkers (median cases 175, median controls 187). Evidence of association was convincing (class I) for maternal pre-pregnancy obesity (OR 1·63, 95% CI 1·49 to 1·77), childhood eczema (1·31, 1·20 to 1·44), hypertensive disorders during pregnancy (1·29, 1·22 to 1·36), pre-eclampsia (1·28, 1·21 to 1·35), and maternal acetaminophen exposure during pregnancy (RR 1·25, 95% CI 1·17 to 1·34). Evidence of association was highly suggestive (class II) for maternal smoking during pregnancy (OR 1·6, 95% CI 1·45 to 1·76), childhood asthma (1·51, 1·4 to 1·63), maternal pre-pregnancy overweight (1·28, 1·21 to 1·35), and serum vitamin D (WMD -6·93, 95% CI -9·34 to -4·51).
INTERPRETATION
Maternal pre-pregnancy obesity and overweight; pre-eclampsia, hypertension, acetaminophen exposure, and smoking during pregnancy; and childhood atopic diseases were strongly associated with ADHD. Previous familial studies suggest that maternal pre-pregnancy obesity, overweight, and smoking during pregnancy are confounded by familial or genetic factors, and further high-quality studies are therefore required to establish causality.
FUNDING
None.
Topics: Acetaminophen; Attention Deficit Disorder with Hyperactivity; Biomarkers; Female; Humans; Pre-Eclampsia; Pregnancy; Pregnancy Complications; Prenatal Exposure Delayed Effects; Protective Factors; Risk Factors
PubMed: 33069318
DOI: 10.1016/S2215-0366(20)30312-6 -
BMJ (Clinical Research Ed.) Oct 2021To examine the associations between dietary intake and tissue biomarkers of alpha linolenic acid (ALA) and risk of mortality from all causes, cardiovascular disease... (Meta-Analysis)
Meta-Analysis
Dietary intake and biomarkers of alpha linolenic acid and risk of all cause, cardiovascular, and cancer mortality: systematic review and dose-response meta-analysis of cohort studies.
OBJECTIVE
To examine the associations between dietary intake and tissue biomarkers of alpha linolenic acid (ALA) and risk of mortality from all causes, cardiovascular disease (CVD), and cancer.
DESIGN
Systematic review and meta-analysis of prospective cohort studies.
DATA SOURCES
PubMed, Scopus, ISI Web of Science, and Google Scholar to 30 April 2021.
STUDY SELECTION
Prospective cohort studies that reported the risk estimates for death from all causes, CVD, and cancer.
DATA SYNTHESIS
Summary relative risks and 95% confidence intervals were calculated for the highest versus lowest categories of ALA intake using random effects and fixed effects models. Linear and non-linear dose-response analyses were conducted to assess the dose-response associations between ALA intake and mortality.
RESULTS
41 articles from prospective cohort studies were included in this systematic review and meta-analysis, totalling 1 197 564 participants. During follow-up ranging from two to 32 years, 198 113 deaths from all causes, 62 773 from CVD, and 65 954 from cancer were recorded. High intake of ALA compared with low intake was significantly associated with a lower risk of deaths from all causes (pooled relative risk 0.90, 95% confidence interval 0.83 to 0.97, I=77.8%, 15 studies), CVD (0.92, 0.86 to 0.99, I=48.2%, n=16), and coronary heart disease (CHD) (0.89, 0.81 to 0.97, I=5.6%, n=9), and a slightly higher risk of cancer mortality (1.06, 1.02 to 1.11, I=3.8%, n=10). In the dose-response analysis, a 1 g/day increase in ALA intake (equivalent to one tablespoon of canola oil or 0.5 ounces of walnut) was associated with a 5% lower risk of all cause (0.95, 0.91 to 0.99, I=76.2%, n=12) and CVD mortality (0.95, 0.91 to 0.98, I=30.7%, n=14). The pooled relative risks for the highest compared with lowest tissue levels of ALA indicated a significant inverse association with all cause mortality (0.95, 0.90 to 0.99, I=8.2%, n=26). Also, based on the dose-response analysis, each 1 standard deviation increment in blood concentrations of ALA was associated with a lower risk of CHD mortality (0.92, 0.86 to 0.98, I=37.1%, n=14).
CONCLUSIONS
The findings show that dietary ALA intake is associated with a reduced risk of mortality from all causes, CVD, and CHD, and a slightly higher risk of cancer mortality, whereas higher blood levels of ALA are associated with a reduced risk of all cause and CHD mortality only.
SYSTEMATIC REVIEW REGISTRATION
PROSPERO CRD42021229487.
Topics: Cardiovascular Diseases; Eating; Humans; Mortality; Neoplasms; Protective Factors; Risk Assessment; alpha-Linolenic Acid
PubMed: 34645650
DOI: 10.1136/bmj.n2213 -
Clinical Nutrition (Edinburgh, Scotland) Jun 2020Maternal vitamin D deficiency has been associated with an increased risk for preeclampsia. Despite this, the current evidence regarding the efficacy of vitamin D... (Meta-Analysis)
Meta-Analysis
BACKGROUND
Maternal vitamin D deficiency has been associated with an increased risk for preeclampsia. Despite this, the current evidence regarding the efficacy of vitamin D supplementation in preventing preeclampsia is controversial. To assess the impact of vitamin D supplementation on the risk of preeclampsia, we performed a systematic review of the literature and a meta-analysis of the available randomized clinical trials (RCTs).
METHODS
The primary outcome was preeclampsia. Subgroup analyses were carried out considering the timing of the supplementation, type of intervention and the study design. Meta-regression analysis, including the amount of vitamin D and maternal age, were planned to explore heterogeneity (PROSPERO database registration number: CRD42019119207).
RESULTS
Data were pooled from 27 RCTs comprising 59 arms, which included overall 4777 participants, of whom 2487 were in the vitamin D-treated arm and 2290 in the control arm. Vitamin D administration in pregnancy was associated with a reduced risk of preeclampsia (odd ratio [OR] 0.37, 95% confidence interval [CI]: 0.26, 0.52; I = 0%). If the vitamin D supplementation was started up to 20 weeks' gestation, the odds was a little lower (OR 0.35, 95% CI: 0.24, 0.50, p < 0.001). The effect was largely independent of the supplementation cessation (until delivery or not), type of intervention (vitamin D alone or in association with calcium), and study design. Increasing dose of vitamin D was associated with reduced incidence of preeclampsia (slope of log OR: -1.1, 95% CI: -1.73, -0.46; p < 0.001).
CONCLUSIONS
Results suggest that vitamin D supplementation may be useful in preventing preeclampsia. These data are especially useful for health-care providers who engage in the management of pregnant women at risk for preeclampsia. Our findings are a call for action to definitively address vitamin D supplementation as a possible intervention strategy in preventing preeclampsia in pregnancy.
Topics: Adolescent; Adult; Avitaminosis; Dietary Supplements; Female; Humans; Incidence; Middle Aged; Pre-Eclampsia; Pregnancy; Protective Factors; Randomized Controlled Trials as Topic; Risk Assessment; Risk Factors; Treatment Outcome; Vitamin D; Young Adult
PubMed: 31526611
DOI: 10.1016/j.clnu.2019.08.015 -
Gastroenterology Oct 2022Many studies have assessed risk factors of irritable bowel syndrome (IBS) and other abdominal pain-related disorders of gut-brain interaction (AP-DGBI); however, the... (Meta-Analysis)
Meta-Analysis
BACKGROUND & AIMS
Many studies have assessed risk factors of irritable bowel syndrome (IBS) and other abdominal pain-related disorders of gut-brain interaction (AP-DGBI); however, the role of these factors is unclear due to heterogeneous study designs. The aim of this systematic review was to extensively evaluate the literature and determine clinical risk and protective factors for the presence and persistence of AP-DGBI in children and adults.
METHODS
A PubMed search identified studies investigating potential risk and protective factors for AP-DGBI in adults and children. Inclusion criteria included fully published studies with a control group; exclusion criteria included poor-quality studies (using a validated scale). For each factor, the proportion of studies that found the factor to be a risk factor, protective factor, or neither was summarized. The number of studies, diagnostic criteria, number of subjects, and average study quality rating provided further context. Whenever possible, a meta-analysis generated pooled odds ratios or mean difference.
RESULTS
The systematic review included 348 studies. Female sex, gastroenteritis, abuse, stress, psychological disorders, somatic symptoms, and poor sleep were consistent risk factors for developing AP-DGBI in adults and children. In adults, additional risk factors included obesity, smoking, and increased use of medical resources. Protective AP-DGBI factors in adults included social support and optimism; no studies for protective factors were found for children.
CONCLUSIONS
There are multiple risk factors for AP-DGBI in adults and children. These include female sex, gastroenteritis, abuse, stress, poor sleep, obesity, psychological disorders, and somatic symptoms. Additional studies are needed in children, on protective factors, and on factors associated with persistence of AP-DGBI.
Topics: Abdominal Pain; Adult; Brain; Child; Female; Gastroenteritis; Gastrointestinal Diseases; Humans; Irritable Bowel Syndrome; Medically Unexplained Symptoms; Obesity; Risk Factors
PubMed: 35716771
DOI: 10.1053/j.gastro.2022.06.028 -
Journal of the American Heart... Oct 2019Background Whether marine omega-3 supplementation is associated with reduction in risk of cardiovascular disease (CVD) remains controversial. Methods and Results This... (Meta-Analysis)
Meta-Analysis
Background Whether marine omega-3 supplementation is associated with reduction in risk of cardiovascular disease (CVD) remains controversial. Methods and Results This meta-analysis included study-level data from 13 trials. The outcomes of interest included myocardial infarction, coronary heart disease (CHD) death, total CHD, total stroke, CVD death, total CVD, and major vascular events. The unadjusted rate ratios were calculated using a fixed-effect meta-analysis. A meta-regression was conducted to estimate the dose-response relationship between marine omega-3 dosage and risk of each prespecified outcome. During a mean treatment duration of 5.0 years, 3838 myocardial infarctions, 3008 CHD deaths, 8435 total CHD events, 2683 strokes, 5017 CVD deaths, 15 759 total CVD events, and 16 478 major vascular events were documented. In the analysis excluding REDUCE-IT (Reduction of Cardiovascular Events with Icosapent Ethyl-Intervention Trial), marine omega-3 supplementation was associated with significantly lower risk of myocardial infarction (rate ratio [RR] [95% CI]: 0.92 [0.86, 0.99]; =0.020), CHD death (RR [95% CI]: 0.92 [0.86, 0.98]; =0.014), total CHD (RR [95% CI]: 0.95 [0.91, 0.99]; =0.008), CVD death (RR [95% CI]: 0.93 [0.88, 0.99]; =0.013), and total CVD (RR [95% CI]: 0.97 [0.94, 0.99]; =0.015). Inverse associations for all outcomes were strengthened after including REDUCE-IT while introducing statistically significant heterogeneity. Statistically significant linear dose-response relationships were found for total CVD and major vascular events in the analyses with and without including REDUCE-IT. Conclusions Marine omega-3 supplementation lowers risk for myocardial infarction, CHD death, total CHD, CVD death, and total CVD, even after exclusion of REDUCE-IT. Risk reductions appeared to be linearly related to marine omega-3 dose.
Topics: Aged; Cardiovascular Diseases; Dietary Supplements; Fatty Acids, Omega-3; Female; Humans; Male; Middle Aged; Protective Factors; Randomized Controlled Trials as Topic; Risk Assessment; Risk Factors; Treatment Outcome
PubMed: 31567003
DOI: 10.1161/JAHA.119.013543 -
Gastroenterology Apr 2021Patients with inflammatory bowel disease (IBD) have an increased risk of colorectal cancer (CRC). We performed a systematic review and meta-analysis to identify all... (Meta-Analysis)
Meta-Analysis
BACKGROUND AND AIMS
Patients with inflammatory bowel disease (IBD) have an increased risk of colorectal cancer (CRC). We performed a systematic review and meta-analysis to identify all prognostic factors for advanced colorectal neoplasia (aCRN, high-grade dysplasia, or CRC) in patients with IBD.
METHODS
A systematic literature search was conducted according to the Meta-analysis Of Observational Studies in Epidemiology (MOOSE) guidelines. Risk of bias was assessed using the Quality in Prognostic Studies tool. Random-effects models were created separately for odds and hazard ratios, different study designs, and univariable or multivariable data. The evidence for all prognostic factors was categorized as "weak", "moderate", or "strong", based on estimate of effect sizes, heterogeneity, and risk of bias.
RESULTS
A total of 164 studies were included, allowing pooled analysis of 31 potential prognostic factors. In the univariable analysis, the evidence for extensive disease was classified as strong while evidence for low-grade dysplasia, strictures, primary sclerosing cholangitis, post-inflammatory polyps, family history of CRC, and ulcerative colitis versus Crohn's disease was considered moderate. Evidence for any dysplasia, colon segment resection, aneuploidy, male sex, and age was classified as weak. In addition, histologic inflammation was identified as a risk factor in multivariable analysis (weak evidence). The evidence for the protective factors colonoscopic surveillance, 5-Aminosalicylic Acid, thiopurines, and smoking was moderate in univariable analysis. Multivariable analysis provided weak evidence for statin use.
CONCLUSIONS
In this systematic review and meta-analysis, we identified 13 risk factors and 5 protective factors for aCRN in IBD patients, based on univariable and/or multivariable pooled analyses. These findings might lay the groundwork for an improved CRC risk stratification-based surveillance in IBD.
Topics: Colitis, Ulcerative; Colitis-Associated Neoplasms; Colorectal Neoplasms; Crohn Disease; Humans; Neoplasm Grading; Prognosis; Protective Factors; Risk Assessment; Risk Factors
PubMed: 33385426
DOI: 10.1053/j.gastro.2020.12.036 -
Journal of Sport and Health Science Jan 2021The aim of this study was to review information about risk factors for lower extremity running injuries in both short-distance (mean running distance ≤20 km/week and...
PURPOSE
The aim of this study was to review information about risk factors for lower extremity running injuries in both short-distance (mean running distance ≤20 km/week and ≤10 km/session) and long-distance runners (mean running distance >20 km/week and >10 km/session).
METHODS
Electronic databases were searched for articles published up to February 2019. Prospective cohort studies using multivariable analysis for the assessment of individual risk factors or risk models for the occurrence of lower extremity running injuries were included. Two reviewers independently selected studies for eligibility and assessed risk of bias with the Quality in Prognostic Studies Tool. The GRADE approach was used to assess the quality of the evidence.
RESULTS
A total of 29 studies were included: 17 studies focused on short-distance runners, 11 studies focused on long-distance runners, and 1 study focused on both types of runners. A previous running-related injury was the strongest risk factor for an injury for long-distance runners, with moderate-quality evidence. Previous injuries not attributed to running was the strongest risk factor for an injury for short-distance runners, with high-quality evidence. Higher body mass index, higher age, sex (male), having no previous running experience, and lower running volume were strong risk factors, with moderate quality evidence, for short-distance runners. Low-quality evidence was found for all risk models as predictors of running-related injuries among short- and long-distance runners.
CONCLUSION
Several risk factors for lower extremity injuries have been identified among short- and long-distance runners, but the quality of evidence for these risk factors for running-related injuries is limited. Running injuries seem to have a multifactorial origin both in short- and long-distance runners.
Topics: Age Factors; Bias; Biomechanical Phenomena; Body Mass Index; Cumulative Trauma Disorders; Female; Gait; Humans; Leg Injuries; Lower Extremity; Male; Multivariate Analysis; Prospective Studies; Risk Factors; Running; Sex Factors; Shoes; Time Factors
PubMed: 32535271
DOI: 10.1016/j.jshs.2020.06.006 -
Breastfeeding Medicine : the Official... Mar 2023The effects of breastfeeding on neurodevelopmental outcomes are unclear. Inconsistent findings have been reported and confounding factors make interpretation of studies... (Review)
Review
The effects of breastfeeding on neurodevelopmental outcomes are unclear. Inconsistent findings have been reported and confounding factors make interpretation of studies difficult. The World Health Organization published a systematic review on breastfeeding and intelligence in 2013, demonstrating a positive association with improved performance on intelligence tests. The objective of this review is to explore published literature since 2013 to examine the association between breastfeeding, cognition, executive function, and behavior. Duplicate searches were carried out using Web of Science and OVID for publications between January 2012 and March 2022. Non-English articles and those not correcting for maternal IQ or home environment were excluded. Twenty-three studies were included, examining the effects of breastfeeding on cognition (21), executive function (3), and behavior (6). Most studies showed a modest dose-dependent increase in cognitive scores in children who were breastfed, test score differences ranging from 0.19 to 0.96 points per month of breastfeeding comparing any breastfeeding, predominant and exclusive breastfeeding. Four out of six studies showed a positive correlation between breastfeeding and behavior. One out of three studies assessing breastfeeding and executive function showed a positive dose-dependent correlation. Recent evidence demonstrates that breastfeeding has a small positive effect on IQ in later childhood. Evidence suggesting that breastfeeding is a protective factor in developing conduct disorders and achieving higher executive function is limited. Further research is required. Limitations include potential confounders and recall bias of breastfeeding.
Topics: Female; Child; Humans; Breast Feeding; Executive Function; Child Development; Time Factors; Intelligence; Cognition
PubMed: 36749962
DOI: 10.1089/bfm.2022.0192 -
Nutrients Jan 2018Heart failure (HF) is a complex syndrome and is recognized as the ultimate pathway of cardiovascular disease (CVD). Studies using nutritional strategies based on dietary... (Review)
Review
BACKGROUND
Heart failure (HF) is a complex syndrome and is recognized as the ultimate pathway of cardiovascular disease (CVD). Studies using nutritional strategies based on dietary patterns have proved to be effective for the prevention and treatment of CVD. Although there are studies that support the protective effect of these diets, their effects on the prevention of HF are not clear yet.
METHODS
We searched the Medline, Embase, and Cochrane databases for studies that examined dietary patterns, such as dietary approaches to stop hypertension (DASH diet), paleolithic, vegetarian, low-carb and low-fat diets and prevention of HF. No limitations were used during the search in the databases.
RESULTS
A total of 1119 studies were identified, 14 met the inclusion criteria. Studies regarding the Mediterranean, DASH, vegetarian, and Paleolithic diets were found. The Mediterranean and DASH diets showed a protective effect on the incidence of HF and/or worsening of cardiac function parameters, with a significant difference in relation to patients who did not adhere to these dietary patterns.
CONCLUSIONS
It is observed that the adoption of Mediterranean or DASH-type dietary patterns may contribute to the prevention of HF, but these results need to be analyzed with caution due to the low quality of evidence.
Topics: Adult; Aged; Aged, 80 and over; Diet, Healthy; Diet, Mediterranean; Diet, Paleolithic; Diet, Vegetarian; Dietary Approaches To Stop Hypertension; Feeding Behavior; Female; Heart Failure; Humans; Incidence; Male; Middle Aged; Nutritional Status; Nutritive Value; Primary Prevention; Protective Factors; Recommended Dietary Allowances; Risk Factors; Risk Reduction Behavior; Treatment Outcome
PubMed: 29320401
DOI: 10.3390/nu10010058