LAUSR

Understanding risky sexual behaviors among adolescents is key in efforts devoted to reducing the health burden related to sexually transmitted infections and unintended or unplanned pregnancies. The aims of this study were to understand the association between number of lifetime sexual partners and time since sexual debut (TSSD) among adolescents and to determine whether sex modified this association. Data were drawn from the 2018-2019 COMPASS-Quebec study, a cohort study conducted in secondary schools in the province of Quebec, Canada. Of 18,467 respondents aged 14 years and older, 6991 (37.9%; mean age 15.3) reported consensual sexual intercourse and answered questions on their age at sexual initiation and number of lifetime sexual partners. Multilevel Poisson regressions with robust standard errors were estimated to adjust for covariates and produce adjusted group mean differences. The adjusted mean number of lifetime sexual partners ranged from 1.5 for those who had recently begun sexual activity (< 12 months) to 4.0 for those who had been active for > 35 months, an average rise of about 0.6 per year. Females-to-males adjusted mean differences showed that males reported more sexual partners than females at all time points, but the differences were only significant at the shorter (< 12 months) and longer (> 35 months) time spans. This study highlights the importance of taking into account TSSD when using and interpreting the number of lifetime sexual partners as risky sexual behavior among adolescents. Sex did not have a significant modifying effect on the relationship between number of lifetime sexual partners and TSSD.