Alcohol and STI risk: evidence from a New Zealand longitudinal birth cohort

Background: The present study examined the associations between involvement with alcohol and risks of sexually transmitted infection (STI) during adolescence and early adulthood.

Methods: A 30-year prospective longitudinal study of the health, development, and adjustment of a birth cohort of 1265 New Zealand-born individuals. Measures included repeated assessments of frequency of alcohol use and number of symptoms of alcohol disorder from ages 15 to 30 and rates of STI from ages 14 to 30. Conditional fixed effects regression models augmented by observed time-dynamic covariate factors were used to control for non-observed confounding in the associations between alcohol and STI risk.

Results: There were clear and consistent trends for increasing involvement with alcohol to be linked with increased risk of STI diagnoses. Adjustment of the associations for sources of non-observed confounding and time-dynamic covariate factors reduced the magnitude of these associations, but they remained statistically significant (p < .05).

Conclusions: The results of the current study support the notion of the existence of a causal pathway in which increasing levels of alcohol use and symptoms of alcohol abuse/dependence led to increased risks of STI exposure. There was little evidence to suggest that the links between alcohol involvement and STI risk could be fully explained by an underlying predisposing factor that increased the risks of both alcohol involvement and STI.