Body mass index and risk of tuberculosis and death : AIDS (original) (raw)

CLINICAL SCIENCE

Hanrahan, Colleen Fa; Golub, Jonathan Eb; Mohapi, Leratoc; Tshabangu, Nkekoc; Modisenyane, Tebogoc; Chaisson, Richard Eb; Gray, Glenda Ec; McIntyre, James Ac; Martinson, Neil Ab,c

aJohns Hopkins Bloomberg School of Public Heath, USA

bJohns Hopkins University Center for TB Research, Baltimore, Maryland, USA

cPerinatal HIV Research Unit, University of the Witwatersrand, Johannesburg, South Africa.

Received 28 January, 2010

Revised 22 March, 2010

Accepted 22 March, 2010

Correspondence to Dr Neil A. Martinson, Perinatal HIV Research Unit, PO Box 144, Diepkloof 1864, Johannesburg, South Africa. Tel: +27 119899703; fax: +27 119899762; e-mail: [email protected]

Abstract

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.