The heritability of alcohol use disorders: a meta-analysis of twin and adoption studies.
Level 1 - systematic review of randomized trials
Meta-analysis of genetically informative observational studies (by design analogy, not clinical CEBM)
PubMed 25171596 · doi:10.1017/S0033291714002165
What was done
Authors conducted a meta-analysis of 12 twin studies and 5 adoption studies evaluating genetic and environmental risk factors for alcohol use disorders (AUDs). Data were reconstructed and analyzed using ordinal data full-information maximum likelihood modeling. Heterogeneity across study design (twin vs. adoption), sex, and diagnostic assessment method (personal interview vs. hospital/population records) was evaluated using likelihood ratio tests.
What was found
The best-fit heritability estimate for AUD was 0.49 (95% CI 0.43-0.53), and the estimated proportion of variance explained by shared environment was 0.10 (95% CI 0.03-0.16). There was no evidence of heterogeneity by study design, sex, or assessment method, though unique environmental variance estimates differed significantly across studies.
Why it matters
This synthesis provides a robust estimate showing that approximately half of the liability for alcohol use disorders is heritable, with consistent findings across distinct genetic epidemiology designs and case ascertainment methods.
Limits
Total participant sample size is not reported in the abstract. Classical twin and adoption models rely on foundational assumptions (such as the equal environments assumption and absence of selective placement or gene-environment correlation), and significant cross-study heterogeneity remained in unique environmental variance estimates.
Cited by
- supports The shared genetic heritability across most addictive substances is estimated to be approximately 0.3 to 0.5.