Persistent long-standing illness and non-drinking over time, implications for the use of lifetime abstainers as a control group.

BACKGROUND: Non-drinkers are shown to have worse health than moderate drinkers in later life. We examine the preceding health status of non-drinkers in early adulthood, and secondly whether persistent poor health is associated with persistent non-drinking.
METHODS: Using two prospective British birth cohort studies established in 1958 (National Child Development Study (NCDS)) and in 1970 (British Cohort Study (BCS)), participants who reported 'never' or 'never had an alcoholic drink' to drinking status questions in successive waves from 23 to 26 years in the NCDS/BCS were derived as 'lifetime abstainers'. Logistic regression on the odds of being a lifetime abstainer was carried out on changes in limiting long-standing illness (LLSI) in the NCDS and long-standing illness (LSI) in the BCS, adjusting for sex, education, poor psychosocial health, marital and parental status.
RESULTS: Participants with an LLSI in consecutive waves since 23 years had 4.50 times the odds of someone who did not have an LLSI of being a lifetime abstainer at 33 years (95% CI 1.99 to 10.18) and 7.02 times the odds at 42 years (2.39 to 20.66) after adjusting for all factors. Similarly, in the BCS, having an LSI in consecutive waves resulted in higher odds of being a lifetime abstainer at 30 years (OR 2.80, 1.88 to 4.18) and 34 years (OR 3.33, 2.01 to 5.53).
CONCLUSIONS: Persistent LSI was associated with remaining a non-drinker across adulthood. Studies comparing the health outcomes of moderate drinkers to lifetime abstainers that do not account for pre-existing poor health may overestimate the better health outcomes from moderate alcohol consumption.