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Abstract
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AIMS: To determine if associations of alcohol consumption with all-cause mortality replicate in discordant monozygotic twin comparisons that control for familial and genetic confounds.
DESIGN: A 30-year prospective follow-up. SETTINGS: Population-based Older Finnish Twin Cohort. PARTICIPANTS: Same-sex twins, aged 24-60 years at the end of 1981, without overt co-morbidities, completed questionnaires in 1975 and 1981 with response rates of 89% and 84%. 15,607 twins were available for mortality follow-up from the date of returned 1981 questionnaires to December 31, 2011. 14,787 twins with complete information were analysed. MEASUREMENTS: Self-reported monthly alcohol consumption, heavy drinking occasions (HDO), and alcohol-induced blackouts. Adjustments for age, gender, marital and smoking status, physical activity, obesity, education and social class.
FINDINGS: Among twins as individuals, high levels of monthly alcohol consumption (≥259 grams/month) associated with earlier mortality (HR = 1.63, 95% confidence interval (CI) = 1.47-1.81). That association replicated in comparisons of all informatively drinking-discordant twin pairs (HR = 1.91, 95% CI = 1.49-2.45) and within discordant monozygotic (MZ) twin pairs (HR = 2.24, 95% CI = 1.31-3.85), with comparable effect size. Smaller samples of MZ twins discordant for HDO and blackouts limited power; a significant association with mortality was found for multiple blackouts (HR = 2.82, 95% CI = 1.30-6.08), but not for HDO.
CONCLUSIONS: The associations of high levels of monthly alcohol consumption and alcohol-induced blackouts with increased all-cause mortality among Finnish twins cannot be explained by familial or genetic confounds; the explanation appears to be causal.
Language: en |