High school students who use drugs and alcohol are more likely than those who do not to engage in activities that put them at risk of contracting sexually transmitted diseases (STDs), including HIV. Male students are more likely than females to take sexual risks, but they also are more likely to use condoms. Risk-takers are more likely than others to socialize frequently with peers, to receive little social support and to believe that they are at high risk of STD infection but that there is little they can do to prevent it. These are the major findings of a study of predominantly ninth-grade urban high school students.1

The researchers recruited study participants from physical education classes at four San Francisco schools in 1991-1992. They asked students to fill out an anonymous questionnaire that included items on the young people's demographic, psychosocial and behavioral characteristics. Psychosocial items covered students' perceptions regarding the acquisition of HIV and other STDs, attitudes toward people with AIDS, anxiety related to STDs, perceptions of friends' attitudes toward preventive health measures, social interactions with peers and social support received from others. Behavioral measures assessed sexual experience, risk-related activities (e.g., having sex with an injection-drug user, an HIV-infected partner or multiple partners), condom use, and alcohol and drug use. The investigators performed two types of analyses: a logistic regression to examine factors associated with sexual experience and a linear regression to explore predictors of sexual risk-taking among sexually experienced young people and condom use in the last month among those who had had intercourse during that period.

In all, 985 students were included in the analysis, 54% of them women. Ninth graders made up 74% of the sample; participants were, on average, 14.7 years old. The sample was ethnically diverse: Thirty-seven percent were Asian, 23% Hispanic, 18% black, 10% white and 12% members of other groups or of mixed ethnicity. Some 38% of the students spoke only English at home, 25% spoke English and another language and 37% spoke another language. The investigators did not obtain information on participants' socioeconomic status; however, using census information and data on public assistance, they calculated that 63% of students in the four schools lived in poor families.

Overall, 30% of respondents were sexually experienced; the average age at first intercourse in this group was 12.7 years. According to the logistic regression results, a number of demographic factors were associated with sexual experience. Males were significantly more likely than females to be sexually experienced (odds ratio, 1.8), and students who spoke only English at home were more likely than those whose families spoke no English to have had intercourse (odds ratio, 1.4). Compared with young people in the "other/mixed ethnicity" category, black and Hispanic respondents had increased odds of sexual experience (2.0 and 1.6, respectively), and respondents from Chinese and other Asian backgrounds had reduced odds (0.3 and 0.5, respectively).

While knowledge about AIDS and other STDs was not associated with sexual experience, respondents who perceived themselves as being at risk of infection were more likely than others to have had intercourse (odds ratio, 1.2). The likelihood of sexual experience also was somewhat elevated among students who socialized frequently with friends (1.1), but it was slightly lowered among those who reported that their friends endorsed preventive health practices (0.9). Students who used alcohol or drugs were more likely than those who did not to have had a sexual experience (1.4).

Results of the linear regression analysis indicated that the factors examined explained 28% of the variation in the likelihood that respondents had engaged in sexual behaviors that put them at risk for STDs. Gender was the only significant demographic factor, accounting for 6% of the variation: Young men were considerably more likely than young women to engage in risky behavior. Psychosocial factors explained 11% of the variation in sexual risk-taking; respondents who perceived themselves as having little ability to prevent STDs, those who socialized frequently with friends and those who reported they received little social support had an elevated likelihood of being risk-takers. Alcohol and drug use also was associated with increased sexual risk-taking, explaining 10% of the variation.

Some 54% of participants who had had intercourse in the previous month reported usually or always using condoms during that period. In all, the variables included in the analysis explained 32% of the variation in condom use. Although male students were more likely than females to engage in risky behavior, they also were more likely to use condoms. In addition, teenagers who perceived that they could prevent STDs and those who thought that their peers approved of preventive health measures had increased chances of using condoms.

The researchers note that while demographic factors were important for predicting sexual experience in their sample, the only one that affected either sexual risk-taking or condom use was gender. Since males are more likely than females both to take sexual risks and to use condoms, the investigators state, it would be helpful to have more information on how males make decisions regarding sexual activity. Commenting on the lack of association in this study between knowledge and behavior, they conclude that while it is "necessary for adolescents to know how STDs/HIV are transmitted and prevented, knowledge alone is not sufficient to influence their risk behaviors." One important factor warranting further study is peer influence. Another is substance use, and the researchers observe that early prevention interventions may avert both premature sexual activity among young people and such negative outcomes as STDs and unintended pregnancies.--M.L. O'Connor


1. Boyer CB, Tschann JM and Shafer M-A, Predictors of risk for sexually transmitted diseases in ninth grade urban high school students, Journal of Adolescent Research, 1999, 14(4):448-465.