The National Health and Nutrition Examination Survey (NHANES) has provided statistics on the health and nutritional status of non-institutionalized, civilian Americans through household interviews and standardized physical examinations since 1971. Beginning in 1999, approximately 5,000 people are examined every year, with data publically released every 2 years. Monitoring national trends in HIV prevalence and associated risk factors using NHANES data can help increase understanding of the health behaviors and characteristics influencing these trends. Doing so, however, requires assessing data over a period of many years because of the relatively low prevalence of HIV in the general population.

For a report published by the CDC, Geraldine M. McQuillan, PhD, and colleagues assessed NHANES data from 2007 to 2012 in order to describe the association of HIV status with key risk factors and examine the prevalence of antiretroviral therapy (ART) use among HIV-infected adults. “For NHANES, people aged 18 to 59 in the general population are surveyed in 15 communities every year,” explains Dr. McQuillan. “A questionnaire asks about demographics, including age, race/ethnicity, household income, and health conditions. Participants also undergo a complex examination that includes phlebotomy to test for, among other things, HIV.”

Due to the low prevalence of HIV in the general population, Dr. McQuillan and colleagues could only assess a few measurements among those with the infection. These included, gender, age, race/ethnicity, education, poverty index, and health insurance status. Other factors assessed in the study included whether or not patients had received healthcare in the past 12 months, the number of lifetime sexual partners, the presence of the herpes simplex antibody, a same-sex sexual contact history, a sexually transmitted infection history, and illicit drug use history.


Room to Improve

The study found that among U.S. adults aged 18-59, 0.39% had HIV. Although relatively low, this estimate remained stable when compared with NHANES data from 1999 to 2006, which found that 0.47% of adults had HIV. Adults with 10 or more lifetime sexual partners (0.68%) and men who reported sexual contact with other men (7.7%) were found to have the highest prevalence estimates of HIV. The prevalence of HIV increased with age, from 0.24% among those aged 18 to 39 years to 0.64% among those aged 50 to 59. Men had a higher prevalence of HIV than women (0.61% vs 0.16%). African Americans had a higher prevalence than all other races/ethnicities combined (1.60%).

“We were  surprised to find that although the prevalence of HIV was much higher in African Americans, less than one-third of African-American adults with HIV were on ART, compared with nearly 90% of Caucasian adults with HIV,” says Dr. McQuillan. “This type of disparity is a major concern, especially as we move closer to universal healthcare. More attention and discussion within the medical community on this topic may be needed.” Overall, nearly half of those with HIV did not report using ART. Rates of ART were higher among men than women and were higher among high-risk sub-groups when compared with others. ART rates also increased with age.


A Call for More Testing

Despite the 2006 recommendation from the CDC to test all patients aged 18 to 65 for HIV, only about half of study participants with HIV knew of their infection. Among those with HIV, nearly one in seven people had never been tested for HIV outside of blood donations. “The CDC recommendations for universal HIV testing may need to be followed in order to capture patients who are HIV positive, make them aware of their status, and get them started on ART,” says Dr. McQuillan. “Only then can we see a substantial decrease in the prevalence of HIV in the general population.”