Systematic analysis for the relationship between obesity and tuberculosis.

OBJECTIVES:Underweight or low body mass index (BMI) is an established risk factor for active tuberculosis. Recent evidence, however, suggests that overweight is associated with lower incidence of tuberculosis. The objective of this systematic review and meta-analysis is to understand the relationship between obesity and tuberculosis and document the extent of association between the two conditions over the range of BMI from underweight to obesity. METHODS:A comprehensive literature search was conducted to identify studies reporting prevalence of the different BMIs in patients with tuberculosis and controls. Thirty studies of adult humans reporting the incidence of tuberculosis at different weight categories were selected for inclusion for meta-analysis in the present study. RESULTS:In tuberculosis, the prevalence of underweight was 3-fold higher than that in controls (P = 0.001) whereas the proportion of overweight and obesity was 2-fold lower (P = 0.001). One unit increase in BMI was associated with 2% reduction in tuberculosis incidence (P < 0.001). Adjusted odds ratio of tuberculosis was 4.96 (95% confidence interval: 4.87-5.05) in underweight and 0.26 in obesity. CONCLUSION:This study further establishes low body weight as a risk factor for tuberculosis whilst overweight and obesity are associated with lower disease risk. Body weight can be considered as a prognostic indictor in the clinical course of tuberculosis.