Observational epidemiologic studies of endemic waterborne risks: cohort, case-control, time-series, and ecologic studies

Observational studies have assessed endemic waterborne risks in a number of countries. Time-series analyses associated increased water turbidity with increased gastroenteritis risks in several public water systems. Several cohort studies reported an increased risk of gastroenteritis in populations using certain public or individual water systems. Although several case-control studies found increased waterborne risks, they also found increased risks associated with other exposures. An increased risk of campylobacteriosis was associated with drinking untreated water from non-urban areas and some tap waters; other significant risks included contaminated poultry and foreign travel. Increased risks of cryptosporidiosis and giardiasis were associated with drinking water in some populations; other risk factors included foreign travel, day care exposures, and swimming. These observational studies provide evidence that some populations may be at an increased risk of endemic or sporadic illness from waterborne exposures, but not all studies found an increased risk. Differences in waterborne risks may be due to differences in water quality. System vulnerabilities and contamination likely differed in the areas that were studied. The information from these studies may help inform estimates of waterborne illness for the US population but is inadequate to estimate a population attributable risk.

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The Association Between Smoking and Hodgkin Lymphoma

Blood ◽

10.1182/blood.v116.21.2560.2560 ◽

2010 ◽

Vol 116 (21) ◽

pp. 2560-2560

Author(s):

Samir Dalia ◽

Jorge J. Castillo

Keyword(s):

Hodgkin Lymphoma ◽

Prospective Studies ◽

Observational Studies ◽

Case Control ◽

Case Control Studies ◽

Current Smoking ◽

Increased Risk ◽

Dissemination Bias ◽

Newcastle Ottawa Scale ◽

Ottawa Scale

Abstract Abstract 2560 Introduction: Few risk factors for the development of Hodgkin lymphoma (HL) have been described. A relationship between smoking and the subsequent development of HL has been suggested from previous reports; however, the available data are largely conflicting. The primary objective of this meta-analysis of observational studies is to evaluate the potential epidemiologic relationship, if any, between smoking and HL. Methods: We searched MEDLINE from January 1, 1960 to June 30, 2010 for observational studies on the association between smoking and HL in adults using the keywords “smoking” and “lymphoma”. Prospective cohort studies and case-control studies that reported relative risks (RR), hazard ratios, or odds ratios with 95% confidence intervals (CI) were included. Literature search, study selection and data gathering were performed independently by the two of authors. Cases were subdivided in ever smokers and current smokers and analyzed separately. Fixed-effect model (FEM) and random-effects models (REM) were used to assess the combined outcome of individual studies. The outcome measured in our study is reported as RR (95% CI). REM was used, if needed, to account for heterogeneity between studies. Heterogeneity was evaluated using the Cochrane Q and I2 statistics. Publication bias was assessed by direct observation of a funnel plot as well as trim-and-fill statistics. Quality of the studies was assessed using the Newcastle-Ottawa scale. Results: Our initial search rendered 577 articles. After reviewing the titles and abstracts, 36 papers were selected for full-text retrieval and reference list search, from which 4 prospective and 11 case-control studies were included in the final analysis. All studies were of high quality with both case-control and prospective studies averaging a score of 8 on the Newcastle-Ottawa scale. When pooling all studies, ever smokers had a RR of 1.20 (95% CI 1.07–1.34; p=0.001); there was no heterogeneity between studies or dissemination bias. Current smokers had a RR of 1.42 (95% CI 1.20–1.68; p<0.001, Figure); there was mild heterogeneity between studies (Q=28.5, I2=45.8%, p=0.046) but no dissemination bias was identified. Based on case-control studies, ever smoking was associated with a RR of 1.16 (95% CI 1.02–1.31; p=0.02) while current smoking was associated with a RR of 1.39 (95% CI 1.14–1.69; p<0.001). Based on prospective studies, ever smoking had a RR 1.40 (95% CI 1.10–1.77; p=0.005) while current smoking had a RR 1.49 (1.02-2.18; p=0.04). Conclusions: In both retrospective and prospective studies, there is a 20% increased risk of developing HL in those patients who have ever smoked. However, the risk increases to 42% in those who were current smokers at time of diagnosis of HL. Our findings confirm a previously reported association between smoking and the development of HL, giving additional support in favor of smoking cessation. The lymphomagenic mechanism of smoking is currently unclear but could be related to a direct carcinogenic effect of tobacco-related agents or the immunomodulatory effect of smoking. Disclosures: No relevant conflicts of interest to declare.

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Association between antipsychotic medication and venous thromboembolism

Irish Journal of Psychological Medicine ◽

10.1017/s0790966700000884 ◽

2010 ◽

Vol 27 (1) ◽

pp. 22-26

Author(s):

Santhana Gunasekaran

Keyword(s):

Venous Thromboembolism ◽

Observational Studies ◽

Case Reports ◽

Case Series ◽

Case Control ◽

Case Control Studies ◽

Antipsychotic Medications ◽

Strength Of Evidence ◽

Increased Risk ◽

Strength Of Association

AbstractObjective: This study aims to identify and review available evidence in the literature to determine the strength of association between antipsychotic medications and thromboembolism as an adverse effect.Method: Electronic databases were searched for evidence.Results: A total of 15 case reports, 14 case series, two observational studies and three case-control studies were found in the literature. Two case control studies found significantly increased risk of venous thromboembolism (OR 13.3 and 7.1 respectively). The risk was high for low potency antipsychotics. Studies were critically appraised to determine the strength of evidence.Conclusion: The studies reviewed indicate a significant association between antipsychotics and venous thromboembolism. Patients using the antipsychotics and those who prescribe them should be aware of this association.

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Adverse cardiovascular events associated with triptans and ergotamines for treatment of migraine: Systematic review of observational studies

Cephalalgia ◽

10.1177/0333102414550416 ◽

2014 ◽

Vol 35 (2) ◽

pp. 118-131 ◽

Cited By ~ 52

Author(s):

G Roberto ◽

E Raschi ◽

C Piccinni ◽

V Conti ◽

L Vignatelli ◽

...

Keyword(s):

Observational Studies ◽

Stroke Risk ◽

Data Extraction ◽

Low Frequency ◽

Case Control ◽

Cochrane Library ◽

Case Control Studies ◽

Safety Issues ◽

Increased Risk ◽

Ischemic Events

Background Apart from the underlying cardiovascular (CV) risk associated with migraine, both triptans and ergotamines can induce vasoconstriction and potentially increase the risk of serious ischemic events. Because of the low frequency of such events in eligible patients, randomized controlled trials are not exhaustive to assess the drug-related CV risk. Observational studies are, therefore, an essential source of information to clarify this matter of concern. Aim The aim of this study was to systematically review the available published observational studies investigating the risk of serious CV events in triptan or ergotamine users, as compared to unexposed migraineur controls. Methods We systematically searched MEDLINE and EMBASE electronic databases for cohort or case-control studies up to December 1, 2013. Studies retrieved from CDSR, DARE and HTA databases of the Cochrane Library were used for snowballing. Studies investigating the risk of any CV outcome in patients with a migraine diagnosis and exposed to triptans or ergotamines were considered for inclusion. Selection of studies, data extraction, and risk of bias assessment were conducted independently by two reviewers. Pooled odds ratios (ORs) with 95% confidence interval (95% CI) were computed using a random-effects model for studies and outcomes judged eligible for quantitative data synthesis. Results From a total of 3370 citations retrieved, after duplicate removal and screening, only four studies met the inclusion criteria (three nested case-control analyses and one retrospective cohort study). These studies investigated the risk of different CV outcomes associated with either the recency or the intensity of exposure to the studied drugs. As for the intensity of use, the pooled OR of serious ischemic events was 2.28 (95% CI 1.18–4.41; I2 = 0%) for ergotamine use (two studies), whereas for triptans (three studies) it was 0.86 (95% CI 0.52–1.43; I2 = 24.5%). Recent use of ergotamines was not significantly associated with any CV outcome (only one available study). Two studies investigated the risk of stroke related to recent triptan use: the first study reported an OR of 0.90 (0.64–1.26), and the second one suggested an increased risk of 2.51 (1.10–5.71). In this case, because of the high degree of heterogeneity, results were not pooled. Conclusions To date, few comparative observational studies have investigated the CV safety of migraine-specific drugs in clinical practice. Evidence gathered here suggests that intense consumption of ergotamines may be associated with an increased risk of serious ischemic complications. As for triptans, available studies do not suggest strong CV safety issues, although no firm conclusions can be drawn. In particular, evidence on stroke risk is conflicting. However, if an increase of the absolute stroke risk in recently exposed patients does actually exist, it must be small. Overall, residual uncontrolled confounding factors reduce the confidence in the risk estimates collected from the included studies. Further investigations are needed to better define the risk for rare but serious CV events related to triptan and ergotamine use for treatment of migraine.

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Is childhood wheeze and asthma in Latin America associated with poor hygiene and infection? A systematic review

BMJ Open Respiratory Research ◽

10.1136/bmjresp-2017-000249 ◽

2018 ◽

Vol 5 (1) ◽

pp. e000249 ◽

Cited By ~ 3

Author(s):

Cristina Ardura-Garcia ◽

Paul Garner ◽

Philip J Cooper

Keyword(s):

Systematic Review ◽

Latin American ◽

Observational Studies ◽

Case Control ◽

Asthma Prevalence ◽

Selective Reporting ◽

Case Control Studies ◽

Cross Sectional ◽

Increased Risk ◽

American Children

IntroductionHigh asthma prevalence in Latin-American cities is thought to be caused by poor hygiene and infections. This contradicts the widely accepted ‘hygiene hypothesis’ for asthma aetiology.MethodsSystematic review of observational studies evaluating the association between poor hygiene exposures or infections and asthma/wheeze among Latin-American children aged 4–16 years. MEDLINE, EMBASE, LILACS and CINAHL electronic databases were searched following a predefined strategy to 18 December 2017. We quantified outcomes measured and reported, assessed risk of bias and tabulated the results.ResultsForty-five studies included: 6 cohort, 30 cross-sectional and 9 case–control studies. 26 cross-sectional studies were school-based surveys (14 of over 3000 children), whereas 5 case–control studies were hospital/health centre-based. Exposures measured and reported varied substantially between studies, and current wheeze was the most common outcome reported. Data showed selective reporting based on statistical significance (P value <0.05): 17/45 studies did not clearly describe the number of exposures measured and 15/45 studies reported on less than 50% of the exposures measured. Most exposures studied did not show an association with wheeze or asthma, except for a generally increased risk associated with acute respiratory infections in early life. Contradictory associations were observed frequently between different studies.ConclusionSelective reporting is common in observational studies exploring the association between environmental exposures and risk of wheeze/asthma. This, together with the use of different study outcomes (wheeze/asthma) associated with possibly distinct causal mechanisms, complicates inferences about the role of poor hygiene exposures and childhood infections in explaining asthma prevalence in Latin-American children.

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The Association Between Red Blood Cell Transfusions and Development of Non-Hodgkin Lymphoma.

Blood ◽

10.1182/blood.v114.22.1376.1376 ◽

2009 ◽

Vol 114 (22) ◽

pp. 1376-1376

Author(s):

Samir Dalia ◽

Sheila Pascual ◽

Jorge Castillo

Keyword(s):

Blood Cell ◽

Publication Bias ◽

Red Blood Cell ◽

Prospective Studies ◽

Observational Studies ◽

Conflicts Of Interest ◽

Case Control ◽

Case Control Studies ◽

Increased Risk ◽

Rbc Transfusion

Abstract Abstract 1376 Poster Board I-398 Introduction: A relationship between red blood cell (RBC) transfusions and the subsequent development of NHL has been suggested from previous observational reports. The mechanism is unclear but could be related to the known immunomodulatory effect of blood transfusion. This report is a meta-analysis of such observational studies and helps clarifying the strength of such an association, if any. Methods: We searched MEDLINE from January 1966 through June 2009 for observational studies on the association between RBC transfusions and NHL in adults using the keywords “transfusion” and “lymphoma”. Prospective studies and case control studies that reported relative risks (RR), hazard ratios or odds ratios with 95% confidence intervals (CI) were included. One author (SD) gathered the data and another (JC) reviewed the data. A fixed-effect model (FEM) was used to assess the combined outcome of individual studies while a random-effects model (REM) was used, if needed, to account for heterogeneity between studies. Heterogeneity was evaluated using the Cochrane Q and I2 statistics. Publication bias was assessed by direct observation of a funnel plot as well as trim-and-fill statistics. Quality of the studies was assessed independently by another author (SP) using the Newcastle-Ottawa scale. Results: Our initial search rendered 1830 articles. After reviewing the abstracts, 21 papers were selected, from which 5 prospective and 9 case-control studies were included in the final analysis. Based on case-control studies, cases receiving RBC transfusions were associated with an RR of 1.37 (95% CI 0.94-1.87) of developing NHL (p=0.11); a REM was used given the heterogeneity found between studies (I2=90%; Q=90.9, p<0.0001). No publication bias was found. Based on prospective studies, RBC transfusions had a RR of 1.57 (95% CI 1.23-1.99) of developing NHL (p=0.0003); a REM was used despite finding minimal heterogeneity (I2=34%; Q=7.7, p=0.17). Publication bias analysis found 2 imputed studies, which would have not altered our results. When pooling data from retrospective and prospective studies, RBC transfusions had a RR of 1.43 (95% CI 1.12-1.84; p=0.005); a REM was used given a high degree of heterogeneity (I2=85%; Q=102.0, p<0.0001). No evidence of publication bias was found when pooling all the studies. Conclusions: In both retrospective and prospective studies, there is an increased risk of developing NHL after getting a RBC transfusion. The possibility that non-diagnosed NHL was the initial indication for transfusions is not addressed by our study, limiting the generalization of our conclusions. After pooling the available data, cases were 43% more likely to develop NHL if they had a RBC transfusion. This risk should be considered non-negligible. Our findings confirm the previously reported association between RBC transfusions and the development of NHL, and further emphasize a conservative approach to RBC transfusions. Disclosures: No relevant conflicts of interest to declare.

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Consumption of Artificially-sweetened Soft Drinks and Risk of Gastrointestinal Cancer: A Meta-analysis of Observational Studies

Public Health Nutrition ◽

10.1017/s136898002100104x ◽

2021 ◽

pp. 1-50

Author(s):

Alfred Jatho ◽

Jansen Marcos Cambia ◽

Seung-Kwon Myung ◽

Keyword(s):

Cohort Studies ◽

Observational Studies ◽

Meta Analysis ◽

Epidemiological Studies ◽

Case Control ◽

Soft Drinks ◽

Case Control Studies ◽

Gi Cancer ◽

Increased Risk ◽

Meta Analyses

Abstract Objective: There remain inconclusive findings from previous observational epidemiological studies on whether consumption of artificially-sweetened soft drinks (ASSDs) increases the risk of gastrointestinal (GI) cancer. We investigated the associations between the consumption of ASSDs and the risk of GI cancer using a meta-analysis. Design: Systematic review and meta-analysis. Setting: PubMed and EMBASE were searched using keywords until May 2020 to identify observational epidemiological studies on the association between the consumption of ASSDs and the risk of GI cancer. Subjects: Twenty-one case-control studies and 17 cohort studies with 12,397 cancer cases and 2,474,452 controls. Results: In the random-effects meta-analysis of all the studies, consumption of ASSDs was not significantly associated with the risk of overall GI cancer (odds ratio (OR)/relative risk (RR), 1.02; 95% CI, 0.92-1.14). There was no significant association between the consumption of ASSDs and the risk of overall GI cancer in the subgroup meta-analyses by study design (case-control studies: OR, 0.95; 95% CI, 0.82-1.11; cohort studies: RR, 1.14; 95% CI, 0.97-1.33). In the subgroup meta-analysis by type of cancer, consumption of ASSDs was significantly associated with the increased risk of liver cancer (OR/RR, 1.28; 95% CI,1.03-1.58). Conclusions: The current meta-analysis of observational epidemiological studies suggests that overall, there is no significant association between the consumption of ASSDs and the risk of GI cancer.

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Diabetes Mellitus and Ovarian Cancer Risk: A Systematic Review and Meta-Analysis of Observational Studies

International Journal of Gynecological Cancer ◽

10.1097/igc.0b013e31828189b2 ◽

2013 ◽

Vol 23 (3) ◽

pp. 402-412 ◽

Cited By ~ 48

Author(s):

Jung-Yun Lee ◽

InPyo Jeon ◽

Jae Weon Kim ◽

Yong-Sang Song ◽

Jae-Moon Yoon ◽

...

Keyword(s):

Ovarian Cancer ◽

Cohort Studies ◽

Observational Studies ◽

Case Control ◽

Cochrane Library ◽

Significant Heterogeneity ◽

Ovarian Cancer Risk ◽

Case Control Studies ◽

Increased Risk ◽

Combining Data

ObjectiveThe objective of this study was to evaluate the epidemiologic association between diabetes and risk of ovarian cancer.MethodsWe searched PubMed, EMBASE, and The Cochrane Library for observational studies on the association between diabetes and ovarian cancer. Cohort studies that reported relative risks (RRs) and case-control studies that showed odds ratios were included in the analysis. Summary RRs with 95% confidence intervals (CIs) were calculated with a random-effects model.ResultsA total of 19 studies from 18 articles (7 case-control studies and 11 cohort studies) met the inclusion criteria. Combining data from all studies, diabetes was associated with an increased risk of ovarian cancer, compared with no diabetes (summary RR of ovarian cancer incidence, 1.17; 95% CI, 1.02–1.33). In cohort and nested case-control studies, patients with diabetes had statistically significant increased risk of ovarian cancer (RR, 1.16; 95% CI, 1.01–1.33), without significant heterogeneity (I2 = 27; P = 0.172). Among studies that control for age, body mass index, smoking, and alcohol, a prominent association between diabetes and ovarian cancer was found (RR, 1.55; 95% CI, 1.11–2.19).ConclusionsThis study suggests that women with diabetes have a moderately increased risk of ovarian cancer.

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Association Between Prediabetes and Erectile Dysfunction: A Meta-Analysis

Frontiers in Endocrinology ◽

10.3389/fendo.2021.733434 ◽

2022 ◽

Vol 12 ◽

Author(s):

Mingyu Jin ◽

Shaoying Yuan ◽

Bo Wang ◽

Luqi Yi ◽

Chenxia Wang

Keyword(s):

Erectile Dysfunction ◽

Observational Studies ◽

Meta Analysis ◽

Random Effect Model ◽

Case Control ◽

Case Control Studies ◽

Cross Sectional ◽

Increased Risk ◽

Subgroup Analyses ◽

Cross Sectional Studies

BackgroundDiabetes has been associated with the increased risk of erectile dysfunction (ED). However, previous studies evaluating the association between prediabetes and ED showed inconsistent results. We performed a meta-analysis of observational studies to systematically evaluate the above association.MethodsRelevant observational studies were retrieved by search of PubMed, Embase, and Web of Science databases. A random-effect model which incorporated the potential intra-study heterogeneity was used for the meta-analysis. Subgroup analyses were performed to evaluate the influences of study characteristics on the outcome.ResultsNine studies (five matched case-control studies and four cross-sectional studies) were included. Age were adjusted or matched in all of the studies. Pooled results showed that compared to men with normoglycemia, men with prediabetes were associated with higher prevalence of ED (odds ratio = 1.62, 95% confidence interval: 1.28 to 2.07, P < 0.001; I2 = 78%). Subgroup analyses showed that the association was not significantly affected by definition of prediabetes, diagnostic tool for ED, or controlling of additional variables besides age (both P for subgroup difference > 0.05). However, the association between prediabetes and ED seemed to be stronger in case-control studies than that in cross-sectional studies, and in studies with younger men (mean age < 50 years) than in those with older men (mean age ≥ 50 years; both P for subgroup difference < 0.05).ConclusionsPrediabetes is associated with higher prevalence of ED, which may be independent of age of the males and may be stronger in young men.

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Population-Based Estimates of the Age-Specific Cumulative Risk of Breast Cancer for Pathogenic Variants in CHEK2: Findings from the Australian Breast Cancer Family Registry

Cancers ◽

10.3390/cancers13061378 ◽

2021 ◽

Vol 13 (6) ◽

pp. 1378

Author(s):

Tú Nguyen-Dumont ◽

James G. Dowty ◽

Jason A. Steen ◽

Anne-Laure Renault ◽

Fleur Hammet ◽

...

Keyword(s):

Breast Cancer ◽

Cumulative Risk ◽

Population Based ◽

Case Control ◽

Cancer Information ◽

Case Control Studies ◽

Breast Cancer Family ◽

Pathogenic Variants ◽

Increased Risk ◽

Control Family

Case-control studies of breast cancer have consistently shown that pathogenic variants in CHEK2 are associated with about a 3-fold increased risk of breast cancer. Information about the recurrent protein-truncating variant CHEK2 c.1100delC dominates this estimate. There have been no formal estimates of age-specific cumulative risk of breast cancer for all CHEK2 pathogenic (including likely pathogenic) variants combined. We conducted a population-based case-control-family study of pathogenic CHEK2 variants (26 families, 1071 relatives) and estimated the age-specific cumulative risk of breast cancer using segregation analysis. The estimated hazard ratio for carriers of pathogenic CHEK2 variants (combined) was 4.9 (95% CI 2.5–9.5) relative to non-carriers. The HR for carriers of the CHEK2 c.1100delC variant was estimated to be 3.5 (95% CI 1.02–11.6) and the HR for carriers of all other CHEK2 variants combined was estimated to be 5.7 (95% CI 2.5–12.9). The age-specific cumulative risk of breast cancer was estimated to be 18% (95% CI 11–30%) and 33% (95% CI 21–48%) to age 60 and 80 years, respectively. These findings provide important information for the clinical management of breast cancer risk for women carrying pathogenic variants in CHEK2.

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Soy Consumption with Risk of Coronary Heart Disease and Stroke: A Meta-Analysis of Observational Studies

Neuroepidemiology ◽

10.1159/000444324 ◽

2016 ◽

Vol 46 (4) ◽

pp. 242-252 ◽

Cited By ~ 11

Author(s):

Danfei Lou ◽

Yuehua Li ◽

Guoliang Yan ◽

Jianhong Bu ◽

Haihui Wang

Keyword(s):

Coronary Heart Disease ◽

Heart Disease ◽

Cohort Studies ◽

Observational Studies ◽

Meta Analysis ◽

Case Control ◽

Inverse Association ◽

Case Control Studies ◽

Relative Risks ◽

Product Consumption

Background: The association of soy product consumption with the relative risk of cardiovascular disease remains controversial. This meta-analysis aimed at investigating whether an association exists between soy consumption and the risk of stroke and coronary heart disease (CHD) in observational studies. Methods: A systematic search of the PubMed and EMBASE databases was performed for case-control and cohort studies that assessed soy consumption and the risk of stroke and CHD. Summary relative risks (SRRs) and 95% CIs were combined by using a random-effects model. Results: Of a total of 1,266 abstracts, 5 prospective cohort and 6 case-control studies met our inclusion criteria, and comprised 4,954 stroke and 7,616 CHD events. Based on the high vs. low analyses, combining cohort studies showed no association between soy intake and risk of stroke (SRR 0.92; 95% CI 0.70-1.10; Pheterogeneity = 0.236; I2 = 29.4%) or CHD (SRR 0.97; 95% CI 0.74-1.27; Pheterogeneity = 0.020; I2 = 62.7%), although a significantly inverse association between soy intake and the risk of stroke (SRR 0.54; 95% CI 0.34-0.87; Pheterogeneity = 0.001; I2 = 79.3%) and CHD (SRR 0.66; 95% CI 0.56-0.77; Pheterogeneity = 0.421; I2 = 0) was observed in case-control studies. No association between soy isoflavone intake and the risk of stroke and CHD was identified. Conclusion: There was limited evidence to indicate that soy consumption was inversely associated with the risk of stroke and CHD, although further studies, with prospective designs that use validated questionnaires and control for important confounders, are warranted.

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