Body mass index and risk of tuberculosis and death

AIDS. 2010 Jun 19;24(10):1501-8. doi: 10.1097/QAD.0b013e32833a2a4a.


Background: High BMI has been shown to be protective against tuberculosis (TB) among HIV-uninfected individuals, as well as against disease progression and mortality among those with HIV. We examined the effect of BMI on all-cause mortality and TB incidence among a cohort of HIV-infected adults in Soweto, South Africa.

Methods: A clinical cohort of 3456 HIV-infected adults from South Africa was prospectively followed from 2003 to 2008 with regular monitoring. The primary exposure was BMI and the outcomes of interest were all-cause mortality and a newly diagnosed episode of TB. Cox proportional hazard models assessed associations with risk of mortality or incident TB.

Results: Incidence rates of mortality were 10.4/100 person-years for baseline BMI of 18.5 or less, 3.6/100 person-years for baseline BMI 18.6-25, 1.7/100 person-years for baseline BMI 25.1-30, and 1.6/100 person-years for baseline BMI more than 30. Compared to those with normal BMI, overweight and obese participants had a significantly reduced risk of mortality [adjusted hazard ratio 0.59 (95% confidence interval, CI 0.40-0.87) and 0.48 (95% CI 0.29-0.80), respectively]. Incidence rates of TB by baseline BMI were 7.3/100 person-years for underweight, 6.0/100 person-years for normal, 3.2/100 person-years for overweight, and 1.9/100 person-years for obese. Compared to those with normal BMI, those with overweight and obese BMI were at a significantly reduced risk of developing TB [adjusted hazard ratio 0.56 (95% CI 0.38-0.83) and 0.33 (95% CI 0.19-0.55), respectively].

Conclusion: HIV-infected individuals with obese and overweight BMI have a significantly reduced risk of both mortality and TB, after adjusting for HAART use and CD4 cell count.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, Non-P.H.S.

MeSH terms

  • AIDS-Related Opportunistic Infections / mortality*
  • Adult
  • Antiretroviral Therapy, Highly Active
  • Body Mass Index*
  • CD4 Lymphocyte Count
  • Cause of Death
  • Female
  • HIV Infections / mortality*
  • HIV-1*
  • Humans
  • Incidence
  • Male
  • Obesity / mortality
  • Prospective Studies
  • Risk Factors
  • South Africa / epidemiology
  • Survival Analysis
  • Thinness / mortality*
  • Tuberculosis / mortality*