Hyacinth Irving

THE RELATION BETWEEN DIFFERENT DIMENSIONS OF ALCOHOL CONSUMPTION AND BURDEN OF DISEASE - AN OVERVIEW

AIMS As part of a larger study to estimate the global burden of disease and injury attributable to alcohol: to evaluate the evidence for a causal impact of average volume of alcohol consumption and pattern of drinking on diseases and injuries; to quantify relationships identified as causal based on published meta-analyses; to separate the impact on mortality versus morbidity where possible; and to assess the impact of the quality of alcohol on burden of disease. METHODS Systematic literature reviews were used to identify alcohol-related diseases, birth complications and injuries using standard epidemiological criteria to determine causality. The extent of the risk relations was taken from meta-analyses. RESULTS Evidence of a causal impact of average volume of alcohol consumption was found for the following major diseases: tuberculosis, mouth, nasopharynx, other pharynx and oropharynx cancer, oesophageal cancer, colon and rectum cancer, liver cancer, female breast cancer, diabetes mellitus, alcohol use disorders, unipolar depressive disorders, epilepsy, hypertensive heart disease, ischaemic heart disease (IHD), ischaemic and haemorrhagic stroke, conduction disorders and other dysrhythmias, lower respiratory infections (pneumonia), cirrhosis of the liver, preterm birth complications and fetal alcohol syndrome. Dose-response relationships could be quantified for all disease categories except for depressive disorders, with the relative risk increasing with increased level of alcohol consumption for most diseases. Both average volume and drinking pattern were linked causally to IHD, fetal alcohol syndrome and unintentional and intentional injuries. For IHD, ischaemic stroke and diabetes mellitus beneficial effects were observed for patterns of light to moderate drinking without heavy drinking occasions (as defined by 60+ g pure alcohol per day). For several disease and injury categories, the effects were stronger on mortality compared to morbidity. There was insufficient evidence to establish whether quality of alcohol had a major impact on disease burden. CONCLUSIONS Overall, these findings indicate that alcohol impacts many disease outcomes causally, both chronic and acute, and injuries. In addition, a pattern of heavy episodic drinking increases risk for some disease and all injury outcomes. Future studies need to address a number of methodological issues, especially the differential role of average volume versus drinking pattern, in order to obtain more accurate risk estimates and to understand more clearly the nature of alcohol-disease relationships.

Alcohol as a Risk Factor for Type 2 Diabetes A systematic review and meta-analysis

OBJECTIVE To clarify the dose-response relationship between alcohol consumption and type 2 diabetes. RESEARCH DESIGN AND METHODS A systematic computer-assisted and hand search was conducted to identify relevant articles with longitudinal design and quantitative measurement of alcohol consumption. Adjustment was made for the sick-quitter effect. We used fractional polynomials in a meta-regression to determine the dose-response relationships by sex and end point using lifetime abstainers as the reference group. RESULTS The search revealed 20 cohort studies that met our inclusion criteria. A U-shaped relationship was found for both sexes. Compared with lifetime abstainers, the relative risk (RR) for type 2 diabetes among men was most protective when consuming 22 g/day alcohol (RR 0.87 [95% CI 0.76–1.00]) and became deleterious at just over 60 g/day alcohol (1.01 [0.71–1.44]). Among women, consumption of 24 g/day alcohol was most protective (0.60 [0.52–0.69]) and became deleterious at about 50 g/day alcohol (1.02 [0.83–1.26]). CONCLUSIONS Our analysis confirms previous research findings that moderate alcohol consumption is protective for type 2 diabetes in men and women.

The more you drink, the harder you fall: a systematic review and meta-analysis of how acute alcohol consumption and injury or collision risk increase together.

Alcohol consumption causes injury in a dose-response manner. The most common mode of sustaining an alcohol-attributable injury is from a single occasion of acute alcohol consumption, but much of the injury literature employs usual consumption habits to assess risk instead. An analysis of the acute dose-response relationship between alcohol and injury is warranted to generate single occasion- and dose-specific relative risks. A systematic literature review and meta-analysis was conducted to fill this gap. Linear and best-fit first-order model were used to model the data. Usual tests of heterogeneity and publication bias were run. Separate meta-analyses were run for motor vehicle and non-motor vehicle injuries, as well as case-control and case-crossover studies. The risk of injury increases non-linearly with increasing alcohol consumption. For motor vehicle accidents, the odds ratio increases by 1.24 (95% CI: 1.18-1.31) per 10-g in pure alcohol increase to 52.0 (95% CI: 34.50-78.28) at 120 g. For non-motor vehicle injury, the OR increases by 1.30 (95% CI: 1.26-1.34) to an OR of 24.2 at 140 g (95% CI: 16.2-36.2). Case-crossover studies of non-MVA injury result in overall higher risks than case-control studies and the per-drink increase in odds of injury was highest for intentional injury, at 1.38 (95% CI: 1.22-1.55). Efforts to reduce drinking both on an individual level and a population level are important. No level of consumption is safe when driving and less than 2 drinks per occasion should be encouraged to reduce the risk of injury.

Alcohol as a risk factor for liver cirrhosis: a systematic review and meta-analysis.

INTRODUCTION AND AIMS Alcohol is an established risk factor for liver cirrhosis. It remains unclear, however, whether this relationship follows a continuous dose-response pattern or has a threshold. Also, the influences of sex and end-point (i.e. mortality vs. morbidity) on the association are not known. To address these questions and to provide a quantitative assessment of the association between alcohol intake and risk of liver cirrhosis, we conducted a systematic review and meta-analysis of cohort and case-control studies. DESIGN AND METHODS Studies were identified by a literature search of Ovid MEDLINE, EMBASE, Web of Science, CINAHL, PsychINFO, ETOH and Google Scholar from January 1980 to January 2008 and by searching the references of retrieved articles. Studies were included if quantifiable information on risk and related confidence intervals with respect to at least three different levels of average alcohol intake were reported. Both categorical and continuous meta-analytic techniques were used to model the dose-response relationship. RESULTS Seventeen studies met the inclusion criteria. We found some indications for threshold effects. Alcohol consumption had a significantly larger impact on mortality of liver cirrhosis compared with morbidity. Also, the same amount of average consumption was related to a higher risk of liver cirrhosis in women than in men. DISCUSSION AND CONCLUSIONS Overall, end-point was an important source of heterogeneity among study results. This result has important implications not only for studies in which the burden of disease attributable to alcohol consumption is estimated, but also for prevention.

Dose-response relationship between alcohol consumption before and during pregnancy and the risks of low birthweight, preterm birth and small for gestational age (SGA)—a systematic review and meta-analyses

Please cite this paper as: Patra J, Bakker R, Irving H, Jaddoe V, Malini S, Rehm J. Dose–response relationship between alcohol consumption before and during pregnancy and the risks of low birthweight, preterm birth and small for gestational age (SGA)—a systematic review and meta‐analyses. BJOG2011;118:1411–1421.

Alcohol consumption and the risk of morbidity and mortality for different stroke types - a systematic review and meta-analysis

BackgroundObservational studies have suggested a complex relationship between alcohol consumption and stroke, dependent on sex, type of stroke and outcome (morbidity vs. mortality). We undertook a systematic review and a meta-analysis of studies assessing the association between levels of average alcohol consumption and relative risks of ischemic and hemorrhagic strokes separately by sex and outcome. This meta-analysis is the first to explicitly separate morbidity and mortality of alcohol-attributable stroke and thus has implications for public health and prevention.MethodsUsing Medical Subject Headings (alcohol drinking, ethanol, cerebrovascular accident, cerebrovascular disorders, and intracranial embolism and thrombosis and the key word stroke), a literature search of MEDLINE, EMBASE, CINAHL, CABS, WHOlist, SIGLE, ETOH, and Web of Science databases between 1980 to June 2009 was performed followed by manual searches of bibliographies of key retrieved articles. From twenty-six observational studies (cohort or case-control) with ischemic or hemorrhagic strokes the relative risk or odds ratios or hazard ratios of stroke associated with alcohol consumption were reported; alcohol consumption was quantified; and life time abstention (manually estimated where data for current abstainers were given) was used as the reference group. Two reviewers independently extracted the information on study design, participant characteristics, level of alcohol consumption, stroke outcome, control for potential confounding factors, risk estimates and key criteria of study quality using a standardized protocol.ResultsThe dose-response relationship for hemorrhagic stroke had monotonically increasing risk for increasing consumption, whereas ischemic stroke showed a curvilinear relationship, with a protective effect of alcohol for low to moderate consumption, and increased risk for higher exposure. For more than 3 drinks on average/day, in general women had higher risks than men, and the risks for mortality were higher compared to the risks for morbidity.ConclusionsThese results indicate that heavy alcohol consumption increases the relative risk of any stroke while light or moderate alcohol consumption may be protective against ischemic stroke. Preventive measures that should be initiated are discussed.

Alcohol consumption and risk of incident human immunodeficiency virus infection: a meta-analysis

ObjectiveTo analyze the relationship between alcohol consumption and incident HIV infection.MethodsArticles were identified via electronic and hand searches. Inclusion criteria were: incident HIV infection, preceding alcohol consumption, and association relating the two. The DerSimonian and Laird random effects model was used. For studies with more than one estimate of a given type, estimates were combined using the inverse variance weighted method. Publication bias was assessed using Begg’s and Egger’s tests. Heterogeneity was assessed using Q and I2 statistics.ResultsTen studies were included. Overall alcohol consumption (any of the three types identified) increased the risk of HIV (RR 1.98, 95% CI 1.59–2.47). Alcohol consumers were at 77% higher risk (RR 1.77, 95% CI 1.43–2.19). Those consuming alcohol prior to, or at the time of, sexual relations were at an 87% increased risk (RR 1.87, 95% CI 1.39–2.50). For binge drinkers, the risk was double that of non-binge drinkers (RR 2.20, 95% CI 1.29–3.74).ConclusionsAlcohol consumption is associated with an increased risk of incident HIV infection. Additional research is required to further investigate a possible causal role.

Alcohol and hypertension: gender differences in dose-response relationships determined through systematic review and meta-analysis.

AIMS To analyze the dose-response relationship between average daily alcohol consumption and the risk of hypertension via systematic review and meta-analysis. DESIGN A computer-assisted search was completed for 10 databases, followed by hand searches of relevant articles. Only studies with longitudinal design, quantitative measurement of alcohol consumption and biological measurement of outcome were included. Dose-response relationships were assessed by determining the best-fitting model via first- and second-degree fractional polynomials. Various tests for heterogeneity and publication bias were conducted. FINDINGS A total of 12 cohort studies were identified from the literature from the United States, Japan and Korea. A linear dose-response relationship with a relative risk of 1.57 at 50 g pure alcohol per day and 2.47 at 100 g per day was seen for men. Among women, the meta-analysis indicated a more modest protective effect than reported previously: a significant protective effect was reported for consumption at or below about 5 g per day, after which a linear dose-response relationship was found with a relative risk of 1.81 at 50 g per day and of 2.81 at an average daily consumption of 100 g pure alcohol per day. Among men, Asian populations had higher risks than non-Asian populations. CONCLUSIONS The risk for hypertension increases linearly with alcohol consumption, so limiting alcohol intake should be advised for both men and women.

Are Lifetime Abstainers the Best Control Group in Alcohol Epidemiology? On the Stability and Validity of Reported Lifetime Abstention

Lifetime abstainers have often been recommended as the comparison group in alcohol epidemiology. The objective of this study was to provide insight into the validity and stability of lifetime abstention by using data derived from the National Alcohol Survey, a national probability survey of US households conducted in 1984, and its 2 follow-up surveys conducted in 1990 and 1992. Results indicated that more than half (52.9%; all proportions were weighted to represent the US population) of those who reported never having a drink of any alcoholic beverage in the 1992 survey reported drinking in previous surveys. Depending on assumptions, this difference may result in an underestimation of alcohol-attributable mortality of 2%−15% in men and 2%−22% in women. Sociodemographic factors differentiated those who consistently reported lifetime abstention across surveys from the rest of the study population. Results suggest that using reported lifetime abstainers as a sole comparison group is problematic, especially if reporting is based on 1 measurement only. Establishing multiple measurement points and including irregular lifetime light drinkers with lifetime abstainers as the comparison group are recommended for future epidemiologic studies.

Alcohol Consumption as a Risk Factor for Atrial Fibrillation: a Systematic Review and Meta-Analysis

Background Alcohol exposure is one of the major risk factors for global burden of disease, but atrial fibrillation (AF) had not yet been included in these estimates. The purpose of this contribution was to examine the dose-response relationship between alcohol consumption and AF and to explore potential causal pathways. Design and methods Systematic literature review and meta-analyses. Results Overall, a consistent dose-response relationship between the amount of alcohol consumed daily and the probability of the onset of AF was found. Women consuming 24, 60 and 120 g of alcohol daily had relative risks of 1.07 [95% confidence interval (CI): 1.04–1.10], 1.42 (95% CI: 1.23–1.64) and 2.02 (95% CI: 1.60–2.97), respectively, relative to nondrinkers. Among men, the corresponding relative risks were 1.08 (95% CI: 1.04–1.11), 1.44 (95% CI: 1.23–1.69) and 2.09 (95% CI: 1.52–2.86). Based on the categorical analyses, we could not exclude the existence of a threshold (three drinks a day for men and two drinks a day for women). Several pathogenic mechanisms for the development of AF in alcohol users were identified. Conclusion Epidemiological criteria for causality were met to conclude a causal impact of alcohol consumption on the onset of AF with a monotonic dose-response relationship. However, the impact of light drinking is not clear.