February 21, 2013
University of Colorado researchers report that middle-aged HIV-infected people with impaired physical function are more likely to have "reduced" bone density and muscle mass, and to produce lower levels of insulin-like growth factor (IGF)-1 and IGF binding protein-3 (IGFBP-3) than high-functioning middle-aged HIV-infected people. The low-functioning patients with these classic aging symptoms also may be more likely to have diseases typical of old age, according to researchers.
To avoid problems like fractures, investigators noted the importance of improving bone density, muscle mass, and hormone levels in middle-aged HIV-infected people with impaired physical function.
The Colorado study included 81 HIV-infected people of similar age, sex, and duration of HIV infection. Thirty-three study participants had low physical function; the control group included 48 high-functioning HIV-infected patients. Study participants had an average age of 53 and a mean CD4 cell count of approximately 600 cells/mm3. Almost all participants (96 percent) had a viral load of less than 50 copies/ml.
Differences in the low-functioning participants and the control group included smoking (half of low-functioning participants and only 12 percent of the control group), osteopenia or osteoporosis of the hip (68 percent of low-functioning participants and 33 percent of the control group), reduced bone mineral density in the lumbar spine (67 percent of low-functioning participants and 38 percent of the control group), and more obesity (20 percent of low-functioning participants and 13 percent of control group. Low-functioning participants were more likely to have less lean muscle mass. Levels of IGF-1 in low-functioning participants were similar to levels associated with people ages 70 to 80 in the general population.
The full report, "Functional Impairment Is Associated with Low Bone and Muscle Mass Among Persons Aging with HIV Infection," was published online in the Journal of Acquired Immune Deficiency Syndromes (2013; doi: 10.1097/QAI.0b013e318289bb7e).