Timing of first alcohol use and alcohol dependence: evidence of common genetic influences.
Level 4 - case-series / case-control
Cross-sectional twin registry study (CEBM Level 4)
PubMed 19686520 · doi:10.1111/j.1360-0443.2009.02648.x
What was done
Researchers analyzed data from 5,382 twins (2,691 complete pairs) aged 24–36 years from the Australian Twin Registry. History of alcohol use, age at first use, and DSM-IV alcohol dependence were assessed using structured telephone interviews to estimate genetic and environmental influences on timing of first alcohol use and alcohol dependence.
What was found
Rates of alcohol dependence were highest in individuals who began drinking at age 14 or younger, following a linear trend in both sexes. Heritability was estimated at 36% for timing of first alcohol use and 53% for alcohol dependence. Shared environmental factors accounted for 15% of the variance in initiation, with no evidence of shared environmental influences on alcohol dependence. The genetic correlation between timing of first alcohol use and alcohol dependence was 0.59.
Why it matters
This indicates that the link between early drinking onset and adult alcohol dependence is largely explained by shared genetic factors rather than environmental causation.
Limits
Timing of first alcohol use and alcohol dependence were measured retrospectively via telephone interview, which introduces recall bias. The sample was restricted to Australian twins aged 24–36, which may limit generalizability to other populations or age groups.
Cited by
- context The age at which someone has their first alcoholic drink is one of the strongest determinants of whether they will develop alcoholism.