Timing of alcohol and other drug use and sexual risk behaviors among unmarried adolescents and young adults.

CONTEXT: Although alcohol and drug use by young people has been associated with sexual risk behavior in some research, detailed data are lacking on the timing of substance use in relationship to sexual risk-taking.

METHODOLOGY: Cross-sectional data on 7,441 unmarried young people aged 14-22 from the 1992 Youth Risk Behavior Survey (household supplement) were used in the analysis. Alcohol and other drug use at last sexual intercourse, substance use in the past 30 days (recent use), the number of different substances ever used (lifetime use) and age at initiation of alcohol use are examined here. The outcome variables assessed through multivariate regression analyses were condom use at last intercourse and more than one sexual partner in the past three months.

RESULTS: Failure to use a condom was strongly associated with the lifetime substance-use scale or, alternatively, with age at initiation of alcohol. Once the number of substances ever used was controlled for, neither substance use at last sexual intercourse nor recent use was associated with the likelihood of using a condom at last coitus. Among young men and women, recent substance use and use of either alcohol or drugs at last intercourse were both strongly associated with having had more than one sexual partner in the past three months. For females only, lifetime use also increased the probability of recent multiple partners.

CONCLUSIONS: The relationships between alcohol and other drug use and two sexual behaviors--condom use and multiple partners-suggest distinct mechanisms of influence and the need for different prevention strategies.