Women tend to gain more weight than men after starting antiretroviral (ARV) treatment for HIV.

Publishing their findings in the Journal of Women’s Health, researchers pooled data from three Phase 3 randomized trials in which U.S. residents began ARV treatment for the first time. Conducted by the AIDS Clinical Trials Group, the three trials were: ACTG A5142, which enrolled participants between 2003 and 2004; ACTG A5202, which enrolled participants between 2005 and 2007; and ACTG A5257, which enrolled participants between 2009 and 2011.

Out of 4,422 participants in these studies, 3,801 met the study’s inclusion criteria, including having data on their body mass index (BMI) before they started ARVs and at the 96-week point after starting treatment.

BMI is calculated by taking a person’s weight in kilograms and dividing it by his or her height in meters squared. A score of 18.5 to 24.9 is considered a healthy body weight, while 25 and above is overweight and 30 and above is obese.

Compared with the men in the studies, the women experienced a mean greater increase in BMI of 1.39 points at week 96. After the researchers adjusted the data to account for differences between participants in their age prior to starting HIV treatment, CD4 count, viral load, race, which study they were in and their specific ARV regimen, this mean greater increase in BMI among men compared with women narrowed to 0.59 points.

The researchers found that pretreatment viral load and CD4 count were associated with a difference in BMI increases between men and women. Consequently, they concluded that having a higher viral load and lower CD4 before beginning ARVs was associated with an even larger difference in BMI increase at treatment week 96 between women and men.

To read the study abstract, click here.