Obesity is now much more common than wasting amongst HIV-positive people in Philadelphia, according to a study published in the August 15th edition of The Journal of Acquired Immune Deficiency Syndromes. The investigators found that 58% of HIV-positive women and 42% of men were either obese or overweight. Risk factors for obesity in women included African-American race and a CD4 cell count above 200 cells/mm3, with CD4 cell count above this level also being associated with obesity in men.
Over 20% of American adults meet the National Institutes of Health criteria for obesity (body mass index [BMI] of 30kg/m2 or above) and over half the US population is thought to be overweight (BMI 25kg/m2 or greater). Obesity and being overweight is known to increase the risk of metabolic complications.
Studies conducted before highly active antiretroviral therapy (HAART) became available suggested that HIV-positive individuals who were obese had slower disease progression and that a high BMI conferred a survival benefit. However, in the HAART era clinicians are becoming concerned that obesity is becoming a significant health issue for HIV-positive patients, particularly women.
There are concerns of an "intersection" between HIV and obesity, and the investigators note, that "obesity predisposes to diabetes and cardiovascular disease, which are complications associated with HIV and/or its treatment."
Because of these concerns, a retrospective cross-sectional analysis was conducted to determine the prevalence of, and risk factors for, obesity amongst patients receiving HIV care in Philadelphia. Investigators also examined the relationship between weight and metabolic complications. A total of 1132 individuals were included in the study.
Individuals were defined as overweight if they had a BMI between 25kg/mg2 and 29.9kg/mg2 with individuals with a BMI above this considered obese.
Median CD4 cell count was 381 cells/mm3. The majority of patients were currently taking HAART, with only 9% being antiretroviral-naïve. In total, 47% had a viral load below 400 copies/ml.
Factors examined for an association with weight were sex, race, age, income, education, drug use, smoking, HAART use, protease inhibitor use, CD4 cell count and viral load.
The prevalence of obesity was 28% in women and 11% in men. Obesity was most common in African American women (30%). Equal proportions of women and men (31% and 30% respectively) were overweight. The investigators also found that overall, 9% of the study population had wasting.
In multivariate analysis in men, a CD4 cell count above 200 cells/mm3 was associated with being obese and overweight (odds ratio = 1.6), but cigarette smoking was protective. In women, African American race (odds ratio = 4.6) and a CD4 cell count above 200 cells/mm3 (odds ratio = 3.2) were associated with obesity and overweight. Once again, cigarette smoking was protective. The investigators warn, however, that "given the potentially increased risk of vascular disease and malignancy in HIV, the high prevalence of smoking in the cohort may be even more deleterious consequences than obesity."
Age, income, employment status, drug use history, use of anti-HIV therapy and viral load were not associated with BMI in the multivariate model.
Investigators also found weak positive correlations between BMI and elevated total cholesterol, LDL-cholesterol, triglycerides and glucose.
The investigators emphasise that the prevalence of obese and overweight HIV-positive individuals identified in their study was, overall, comparable to that of the general population of Philadelphia. Indeed, they note that for the 30 – 44 and 44 – 64 age groups, the prevalence of obese and overweight HIV-positive individuals was actually significantly lower than in the general city population (p = 0.001 and p
"Our data suggest that being overweight or obese is common in an urban HIV population, a reflection of the obesity epidemic in Philadelphia", comment the investigators. They conclude, "in an obese patient with abnormal metabolic characteristics, lifestyle modification and weight loss interventions to achieve a healthy weight are likely to be beneficial." However, they add, "optimum intervention strategies need to be established."
Amorosa V et al. A tale of two epidemics. The intersection between obesity and HIV infection in Philadelphia. J Acquir Immune Defic Syndr: 39 (5): 557 – 561, 2005.