February 26, 2003
Janet E. Forrester and colleagues at Tufts University School of Medicine reported that "HIV-positive adults were seen at semiannual clinic visits, at which time weight, fat, and fat-free mass were determined. The unit of analysis was the person-interval." The full report, "Weight Loss and Body-Composition Changes in Men and Women Infected with HIV," was published in the American Journal of Clinical Nutrition (2002;76(6):1428-1434).
The researchers reported that "551 persons contributed 2,266 intervals of data, of which 311 (14 percent) were intervals in which weight loss was greater than or equal to 5 percent of initial (start of interval) weight. Of these, 208 (67 percent) intervals met the criteria for analysis (123 from men and 85 from women). Loss of fat-free mass was dependent on the initial percentage of body fat in the men with less than 32 percent body fat. A plot of the initial percentage of body fat compared with loss of fat-free mass (kg) suggested a nonlinear relation over the range of body fat examined. There was no clear relation between the initial percentage of body fat and loss of fat-free mass in women."
"In men with HIV-associated weight loss, the weight lost as fat-free mass depends on the initial percentage of body fat at low levels of body fat but appears to be independent of initial percentage of body fat at high levels of body fat. In women with HIV-associated weight loss who have normal-to-high body fat stores, loss of fat-free mass is independent of the initial percentage of body fat," the researchers concluded.