Trends in HIV-Related Risk Behaviors Among High School Students — United States, 1991–2011

On July 24, 2012, this report was posted as an MMWR Early Release on the MMWR website (http://www.cdc.gov/mmwr).

One of the three primary goals of the National HIV/AIDS Strategy for the United States is to reduce the number of persons who become infected with human immunodeficiency virus (HIV) (1). In 2009, persons aged 15–29 years comprised 21% of the U.S. population but accounted for 39% of all new HIV infections (2). Sexual intercourse, sexual intercourse with multiple partners, sexual intercourse without using a condom, and injection drug use are behaviors that increase risk for HIV infection. To describe trends in the prevalence of HIV-related risk behaviors among high school students, CDC analyzed data from the biennial national Youth Risk Behavior Survey (YRBS) for the period 1991–2011. The results of that analysis indicated that, although the percentage of students overall who had ever had sexual intercourse decreased significantly from 54.1% in 1991 to 47.4% in 2011, the prevalence of ever having had sexual intercourse did not change significantly after reaching 45.6% in 2001. Similarly, although the percentage of students who had four or more sex partners decreased significantly from 18.7% in 1991 to 15.3% in 2011, the prevalence of having four or more sex partners did not change significantly after reaching 14.2% in 2001. Condom use at most recent sexual intercourse among students currently having sexual intercourse increased from 46.2% in 1991 to 60.2% in 2011. However, the prevalence of condom use did not change significantly beginning in 2003 (63.0%). The prevalence of injection drug use among students overall did not change significantly from 1995 (2.1%) to 2011 (2.3%). The results suggest that progress in reducing some HIV-related risk behaviors among high school students overall and in certain populations did not change significantly in the past decade. To reduce the number of young persons who become infected with HIV, renewed educational efforts and other risk reduction interventions are warranted.

The national YRBS, a component of CDC's Youth Risk Behavior Surveillance System, used independent, three-stage cluster samples for the 1991–2011 biennial surveys to obtain cross-sectional data representative of public and private school students in grades 9–12 in all 50 states and the District of Columbia (3). Sample sizes in the surveys ranged from 10,904 to 16,410. School response rates ranged from 70% to 81%, student response rates ranged from 83% to 90%, and overall response rates* ranged from 60% to 71%.

For each survey, students completed anonymous, self-administered questionnaires that included identically worded questions about their sexual experience, number of sexual intercourse partners, current sexual intercourse, condom use, and injection drug use.† Sexual experience was defined as ever having had sexual intercourse. Having multiple sex partners was defined as having sexual intercourse with four or more persons during their life. Current sexual activity was defined as having sexual intercourse with at least one person during the 3 months before the survey. Condom use was defined as using a condom during the most recent sexual intercourse among currently sexually active students. Injection drug use was defined as using a needle to inject any illegal drug into their body one or more times during their life. Data by race/ethnicity are presented for black, white, and Hispanic students only. The three populations are mutually exclusive. All black and white students were non-Hispanic; Hispanic students might be of any race. The numbers of students from other racial/ethnic populations were too small for meaningful trend analysis.

Data were weighted to provide national estimates, and the statistical software used for all analyses accounted for the complex sample design. Changes over time during 1991–2011 were analyzed using logistic regression analyses that controlled for sex, race/ethnicity, and grade and simultaneously assessed significant (p<0.05) linear and quadratic time effects.§ T-tests were used to test for significant (p<0.05) differences between prevalence estimates for 2009 and those for 2011.

During 1991–2011, a significant linear decrease occurred in the prevalence of sexual experience overall and among male, female, black, and white high school students (overall: 54.1% to 47.4%; male: 57.4% to 49.2%; female: 50.8% to 45.6%; black: 81.5% to 60.0%; and white: 50.0% to 44.3%) (Table). Among Hispanic students, no significant change was detected. Overall and among male and white students a significant quadratic trend also occurred. Overall, the prevalence of sexual experience decreased during 1991–2001 and then did not change significantly during 2001–2011 (54.1% to 45.6%, and then 47.4%). Among male students, the prevalence of sexual experience decreased during 1991–1997 and then did not change significantly during 1997–2011 (57.4% to 48.9% and then 49.2%), and among white students the prevalence of sexual experience decreased during 1991–2003 and then did not change significantly during 2003–2011 (50.0% to 41.8% and then 44.3%). The prevalence of sexual experience was lower in 2011 compared with 2009 among black students (65.2% to 60.0%), but not but not overall or among either sex or any other racial/ethnic population.

A significant linear decrease occurred during 1991–2011 in the prevalence of having four or more sex partners overall and among male, female, black, and white high school students (overall: 18.7% to 15.3%; male: 23.4% to 17.8%; female: 13.8% to 12.6%; black: 43.1% to 24.8%; and white: 14.7% to 13.1%) (Table, Figure 1). Among Hispanic students, no significant change was detected. Overall and among male and white students a significant quadratic trend also occurred. Overall, the prevalence of having four or more sex partners decreased during 1991–2001 and then did not change significantly during 2001–2011 (18.7% to 14.2% and then 15.3%). Among male students, the prevalence of having four or more sex partners decreased during 1991–2005 and then did not change significantly during 2005–2011 (23.4% to 16.5% and then 17.8%), and among white students the prevalence of having four or more sex partners decreased during 1991–2003 and then did not change significantly during 2003–2011 (14.7% to 10.8% and then 13.1%). The prevalence of having four or more sex partners was higher in 2011 compared with 2009 among white students (13.1% to10.5%), but not overall or among either sex or any other racial/ethnic population.

During 1991–2011, a significant linear decrease occurred in the prevalence of current sexual activity overall and among male, female, and black high school students (overall: 37.5% to 33.7%; male: 36.8% to 33.3%; female: 38.2% to 34.2%; and black: 59.3% to 41.3%) (Table). Among Hispanic and white students, no significant change was detected. The prevalence of current sexual activity was lower in 2011 (41.3%) compared with 2009 (47.7%) among black students, but not overall or among either sex or any other racial/ethnic population.

A significant linear increase occurred during 1991–2011 in the prevalence of condom use among currently sexually active students overall and among both sexes and all three racial/ethnic populations (overall: 46.2% to 60.2%; male: 54.5% to 67.0%; female: 38.0% to 53.6%; black: 48.0% to 65.3%; Hispanic: 37.4% to 58.4%; and white: 46.5% to 59.5%) (Table, Figure 2). In addition, a significant quadratic trend occurred overall and among both sexes and all three racial/ethnic populations. Overall and among female and white students, condom use increased during 1991–2003 and then did not change significantly during 2003–2011 (overall: 46.2% to 63.0% and then 60.2%; female: 38.0% to 57.4% and then 53.6%; and white: 46.5% to 62.5% and then 59.5%). Among male students, condom use increased during 1991–2005 and then did not change significantly during 2005–2011 (54.5% to 70.0% and then 67.0%). Among Hispanic students, condom use increased during 1991–2007 and then did not change significantly during 2007–2011 (37.4% to 61.4% and then 58.4%). Among black students, condom use increased during 1991–1999 and then decreased during 1999–2011 (48.0% to 70.0% to 65.3%).

During 1995–2011, a significant linear increase occurred in the prevalence of injection drug use among black and Hispanic students (black: 1.1% to 2.4%; and Hispanic: 2.2% to 2.9%) (Table). Overall and among male, female, and white students, no significant change was detected.

Reported by

Laura Kann, PhD, Richard Lowry, MD, Danice Eaton, PhD, Howell Wechsler, EdD, Div of Adolescent and School Health, National Center for HIV/AIDS, Viral Hepatitis, STD, and TB Prevention, CDC. Corresponding contributor: Laura Kann, lkann@cdc.gov, 770-488-6181.

Editorial Note

The findings in this report suggest that previously reported progress in reducing some HIV-related risk behaviors among students (4) stalled overall and among certain populations of students. Most concerning are the decrease in condom use among black students since 1999 and the lack of any significant decrease since 1991 in the percentage of Hispanic students who have had sexual intercourse, four or more sex partners, and current sexual activity.

Another of the three primary goals of the National HIV/AIDS Strategy for the United States is to reduce HIV-related health disparities. In 1991, a gap of 32 percentage points was observed in sexual experience prevalence between black and white students (black: 81.5%; white: 50.0%). In 2011, this gap had been reduced to 16 percentage points (black: 60.0%; white: 44.3%). Large differences between black and white students in the prevalence of having four or more sex partners and current sexual activity also have been reduced over time. Nonetheless, black students still report significantly higher prevalence of sexual risk behaviors than white or Hispanic students and remain at increased risk for HIV infection and sexually transmitted diseases, a finding that underscores the importance of the decreasing trend in condom use among black students since 1999. YRBS data cannot isolate the effects of race/ethnicity from the effects of other factors on the prevalence of HIV-related behaviors. Additional research is needed to assess the effects of education, socioeconomic status, and cultural factors on the prevalence of these behaviors and to help intensify HIV prevention efforts in the communities where HIV infection is most heavily concentrated (1).

The findings in this report are subject to at least two limitations. First, these data apply only to youths who attend school and therefore are not representative of all persons in this age group. Nationwide, in 2009, of persons aged 16–17 years, approximately 4% were not enrolled in a high school program and had not completed high school (5). Second, the extent of underreporting or overreporting of self-reported behaviors cannot be determined, although the survey questions demonstrate good test-retest reliability (6).

The National HIV/AIDS Strategy for the United States recommends educating young persons about HIV before they begin engaging in behaviors that place them at risk for HIV infection (1), and the Community Preventive Services Task Force recommends risk reduction interventions to prevent HIV infection among adolescents (7). Although in another study a median of 90% of all public secondary schools in 45 states taught HIV prevention in a required course during 2010, the percentage that taught 16 specific topics varied widely (8).

To achieve the National HIV/AIDS Strategy for the United States goal of reducing the number of persons who become infected with HIV, further improvements in the prevalence of behaviors that contribute to HIV infection among young persons are needed. Renewed educational efforts that reach all students before risk behaviors are initiated and that seek to delay the onset of sexual activity, increase condom use among students who are sexually active, and decrease injection drug use are warranted.

References

1. Office of National AIDS Policy. National HIV/AIDS strategy for the United States. Washington, DC: The White House, Office of National AIDS Policy; 2010. Available at http://www.whitehouse.gov/sites/default/files/uploads/NHAS.pdf. Accessed July 20, 2012.
2. CDC. HIV among youth. Atlanta, GA: US Department of Health and Human Services, CDC; 2011. Available at http://www.cdc.gov/hiv/youth/index.htm. Accessed July 20, 2012.
3. CDC. Youth Risk Behavior Surveillance—United States, 2011. MMWR 2012;61(No. SS-4).
4. Eaton DK, Lowry R, Brener ND, Kann L, Romero L, Wechsler H. Trends in human immunodeficiency virus- and sexually transmitted disease-related risk behaviors among U.S. high school students, 1991–2009. Am J Prev Med 2011;40:427–33.
5. National Center for Education Statistics. Common core of data: public elementary/secondary school universe survey. Washington, DC: US Department of Education, National Center for Education Statistics. Available at hhtp://nces.ed.gov/ccd. Accessed July 20, 2012.
6. Brener ND, Kann L, McManus T, Kinchen SA, Sundberg EC, Ross JG. Reliability of the 1999 Youth Risk Behavior Survey questionnaire. J Adolesc Health 2002;31:336–42.
7. CDC. Guide to community preventive services. Prevention of HIV/AIDS, other STIs and pregnancy: group-based comprehensive risk reduction interventions for adolescents. Atlanta, GA: US Department of Health and Human Services, CDC; 2010. Available at http://www.thecommunityguide.org/hiv/riskreduction.html. Accessed July 20, 2012.
8. CDC. HIV, other STD, and pregnancy prevention education in public secondary schools—45 states, 2008–2010. MMWR 2012;61:222–8.