Gay men may shift in and out of levels of risk for acquiring HIV, aidsmap reports. Seeking information to help tailor a more cost-effective approach to targeting pre-exposure prophylaxis at the right subgroups of gay men, investigators drew a sample of 419 gay men from the U.S. Multicenter AIDS Cohort Study. The men were HIV negative and recruited between 2001 and 2003. They were seen by investigators between January 2003 and September 2004 and at least once more up until September 2011. The investigators published their results in the Journal of Acquired Immune Deficiency Syndromes.

During semi-annual visits, the researchers asked the men about their sexual behavior over the previous six months. They scored the men’s riskiest sexual behavior on a scale of zero to six, with zero being no anal intercourse and six being unprotected receptive anal intercourse with at least one HIV-positive partner or partner of an unknown HIV status. The investigators then categorized the men into “low,” “medium” and “high” risk groups to reflect their average risk behavior across the study.

According to their average risk behavior across the study, the participants were divided into the following categories: 63 percent were low risk, 23 percent moderate risk and 14 percent high risk. One in three of those who were high risk became HIV positive during the study, as did one in 10 of those in the moderate group.

The study group as a whole was not necessarily reflective of the general gay population in part because of a selection bias: The study may have attracted a larger proportion of men who were particularly motivated toward HIV prevention.

Those in the average low-risk group generally did not vacillate into one of the other categories at any given time. Meanwhile, in the earlier part of the study, 29 percent of those in the average moderate-risk group were likely to report high-risk behavior in the following six-month period, a figure that dropped to 17 percent by the end of the study. Meanwhile, of those in the average high-risk group, just 29 percent dropped into the moderate-risk group during the next half of a year.

Having an income above $20,000 a year was the factor most strongly linked to being in the high-risk group: Those in this income bracket were five times more likely to fall into the high-risk category than those with lesser incomes. Being white was most strongly linked to being in the moderate- or high-risk group, as opposed to being black or Hispanic: White men had a 3.9-fold greater chance of being in the moderate-risk group and a 3.7-fold greater chance of being in the high-risk group when compared with the other ethnic groups.   

To read the aidsmap story, click here.

To read the study abstract, click here.