Even if black young adults participate only in low-risk behaviors, their prevalence of STDs, including HIV, is higher than the national average for their age-group, according to analyses based on Wave 3 of the National Longitudinal Study of Adolescent Health (Add Health).1 In contrast, STD prevalence among white young adults exceeds the average of 6% only if they engage in certain high-risk behaviors. And in general, among young adults who fit a given behavioral risk profile, blacks are more likely than whites to have an STD.

Wave 3 Add Health interviews were conducted in 2001–2002, when participants were between 18 and 26 years of age. Respondents were questioned about their socioeconomic characteristics, sexual behavior and substance use, and were asked to provide saliva and urine samples to be tested for HIV and other STDs (chlamydia, gonorrhea and trichomoniasis), respectively. Given documented racial disparities in infection rates, the analysts examined prevalence separately for whites and blacks. To explore the causes of racial disparities, they calculated race-specific prevalence rates associated with each of 15 discrete patterns of risky behavior (three well-recognized ones and 12 that they identified through cluster analysis). They also used logistic regression to compare the likelihood of infection between whites and blacks by behavioral pattern, controlling for differences in socioeconomic characteristics.

The analyses included 8,706 survey participants for whom complete STD and HIV data were available—6,257 white and 2,449 black young adults. Members of the analytic sample were 22 years old, on average; 17% were married, 15% were high school dropouts and 15% were functionally poor (i.e., lived in households that did not have enough money to pay the rent or mortgage or a utility bill). Eight in 10 respondents had had intercourse in the past year, and 60% of this group had not used a condom at last sex; one-fifth of those who were sexually experienced had first had intercourse before age 15.

In all, 6% of the sample tested positive for chlamydia, gonorrhea, trichomoniasis or HIV; 10% of those with any infection had two or more. Blacks had a higher overall prevalence of infection than whites (19% vs. 3%) and a higher rate of each type of infection. In bivariate analyses, other significant correlates of infection were being unmarried, having dropped out of high school, being functionally poor and having become sexually experienced before age 15. Condom use at last sex was not associated with the prevalence of infection.

For the sample as a whole, the most normative behavioral pattern was characterized by reporting few sexual partners since 1995 and little use of alcohol, drugs or tobacco. This was the most common pattern among blacks, accounting for 38% of black respondents. Whites were more evenly distributed among the 15 patterns; the largest proportion of white participants (14%) fit a pattern defined by light alcohol consumption and few sexual partners since 1995. The least normative pattern of behavior, reported by no more than 1% of respondents of either race, reflected heavy marijuana use and use of other illegal drugs.

Among white respondents in 11 of the 15 behavioral groups, the prevalence of any infection was 5% or less—lower than the 6% prevalence for young adults overall. In the four least normative and most risky categories (characterized by injection-drug use, exchange of sex for money, sexual activity between males and use of marijuana and other illegal drugs), prevalence among whites ranged from 7% to 9%. By contrast, even the lowest prevalence among blacks (10%, observed among those who had had eight or more sexual partners since 1995) exceeded the average for the sample; rates were 20% or more in nine risk categories and reached 34% among men who had sex with men.

With few exceptions, blacks were at significantly greater risk of STD infection than whites in a given behavioral group, and the differences were often large. For example, the odds of infection were 10 times as high among black males who reported same-sex activity as among white males in this behavioral category; they were 25 times as high among blacks as among whites who were at low risk because their level of substance use was low and they either were sexually inexperienced or had not had sex in the past year. No significant racial differences were found among respondents who reported multiple partners, those who had traded sex for money or those who used injection drugs. (However, the small number of injection-drug users limited the potential for identifying statistically significant differences in reports of the behavior.)

As the researchers point out, STD and HIV prevention efforts typically address individual-level risk behaviors. However, according to the analysts, “this strategy may be appropriate for whites (because their STD risk increases only when their behavior is very risky) but not for blacks,” who are at very high risk “even when their behavior is normative.” For blacks, they contend, population-level interventions should focus on the “environmental, institutional and contextual” disadvantages that likely contribute to racial disparities in STD rates. Among their recommendations are media efforts to inform blacks of their high risk of STD infection and encourage young blacks to seek regular testing, expansion of STD services to nontraditional venues and surveillance of both prevalence and testing. Noting that “most STDs can be cured, and the health and life span of individuals infected with HIV can be greatly increased by current therapies,” the researchers urge “appropriate efforts” to lower disease rates. —D. Hollander


1. Hallfors DD et al., Sexual and drug behavior patterns and HIV and STD racial disparities: the need for new directions, American Journal of Public Health, 2007, 97(1):125–132.