In the U.S., as we move into the holiday season there is often increased reporting on obesity. HIV.gov asked Dr. Nancy F. Crum-Cianflone, a Research Physician with the Naval Medical Center San Diego, to provide us information on her new study of obesity in HIV-infected persons. Research has shown, HIV-infected persons are now are increasingly overweight or obese. Below is what she told us.
Obesity among HIV-infected persons: Impact of Weight on CD4 Cell Count
Since the availability of highly potent HIV medications in the mid-1990s, HIV-infected persons are less often suffering from wasting, but rather they now are increasingly overweight or obese. Prior studies have shown that obesity leads to negative health consequences in the general population including heart disease, diabetes, and certain cancers. We performed our study to evaluate if obesity could have additional health consequences among HIV-positive persons, specifically if obesity could affect their immune systems, as measured by their CD4 cell counts.
We evaluated over 1,000 HIV-infected persons as part of the US Military Natural History Study conducted at 7 HIV Clinics across the U.S. Participants of our study had known dates of HIV infection and had data on both weight measurements and immune cells over time. Statistical methods to evaluate the relationship of weights over time with changes in the CD4 counts included linear mixed effects models.
Of 1,119 HIV seroconverters in our study, 441 (39%) were overweight, 96 (9%) obese, and 12 (1%) were underweight at HIV diagnosis. The mean age of our study cohort was 29 years; 96% were male; 44% were Caucasian, 41% African American, and 15% other races.
We found that since the availability of highly potent HIV medications in the mid-1990s, HIV patients who were obese were more likely to have lower CD4 counts than those whose weight was appropriate. Specifically the mean post-HIV diagnosis change in CD4 counts over time was +103 for normal weight persons and +69 cells/mm3 for those who were obese. This difference was statistically significant.
In addition, we found that after beginning HIV medications for the first time, obese persons gained fewer CD4 cells than overweight persons. We also noted that underweight persons had overall lower CD4 counts than normal weight persons, emphasizing the importance of maintaining an appropriate weight.
In summary, our study found that those who were obese had lower CD4 cell counts than those of normal weights. These data suggest that lower CD4 counts may be another adverse consequence of being obese. Our study results should encourage HIV patients to achieve and maintain normal weights. As such, weight monitoring and maintenance programs may now be important components of HIV care.
Thanks to Vera Yakovchenko for her help in preparing this blog post.