Factors Associated with Sexual Debut in Mexican Adolescents: Results of the National Survey on Drug Use among Students in 2014

Abstract

Introduction: Although first sexual experience (understood as first sexual intercourse) is one of the most commonly assessed characteristics of adolescents, recent research emphasizes the importance of understanding other related social factors. This study highlights factors associated with first sexual experience in a nationally representative sample of adolescent students in Mexico.

Aims: The goals of this study were (i) to determine the proportion of adolescents aged 12-17 who had had their first sexual experience; (ii) to identify the factors associated with first sexual experience; and (iii) to analyze the conditions (condom use, substance use) in which first sexual experience takes place.

Method: The data presented in this study are drawn from the 2014 National Survey on Drug Use in Students (Spanish acronym ENCODE), undertaken with the purpose of identifying the prevalence of drug use and associated variables, including sexual activity, in Mexican students. Kaplan-Meier analysis was used to estimate the probability of first sexual experience at a given age, taking sex as an outcome variable and age as a follow-up period. Logistic regression was used to assess possible factors for sexual initiation.

Main outcome measures: Validated standard questionnaires were used to assess sociodemographic characteristics, first sexual experience (framed as first sexual intercourse), frequency of sexual relations, sexual partners, sexual preference (framed as preferred sex of partners), substance use, having a physical illness or a behavioral problem, condom or other contraceptive use, as well as the absence or presence of parents, parents' educational attainment, and parents' substance use.

Results: A total of 26,187 students aged 12-17 participated. Of this total, 14.8% had already had their first sexual experience, at a median age of 15; 64.5% used some type of contraceptive, and 53.2% used condoms. Proportional probabilities for having first sexual experience using age as a follow-up period showed that the probability of having sex earlier was higher among boys than girls: the probability of having sex at age of 15 was 26.5% for boys and 13.9% for girls. Predictors of first sexual experience included substance use (alcohol OR = 2.5, tobacco OR = 2.6, and other drugs OR = 2.3), having a mother who used drugs (OR= 2.2), sexual preference (female homosexual, OR = 2.2), and sex (male, OR = 2.1).

Conclusions: Boys are more likely to have had a first sexual experience than girls. Future strategies should incorporate specifically targeted elements with different messages that consider adolescents' sex and age. Barragán V, Berenzon S, Tiburcio M, et al. Factors Associated with Sexual Debut in Mexican Adolescents: Results of the National Survey on Drug Use among Students in 2014. J Sex Med 2019;16:418-426.

Keywords: Adolescents; Condom Use; First Sexual Experience; National Survey; Substance Use.