Publication Date



PLoS One


BACKGROUND: Studies show obesity decreases risk of tuberculosis (TB) disease. There is limited evidence on whether high body mass index also protects against TB infection; how very high body mass indices influence TB risk; or whether nutritional status predicts this risk in children. We assessed the impact of body mass index on incident TB infection and disease among adults and children.

METHODS AND FINDINGS: We conducted a prospective cohort study among household contacts of pulmonary TB cases in Lima, Peru. We determined body mass index at baseline and followed participants for one year for TB infection and disease. We used Cox proportional regression analyses to estimate hazard ratios for incident TB infection and disease. We enrolled 14,044 household contacts, and among 6853 negative for TB infection and disease at baseline, 1787 (26.1%) became infected. A total of 406 contacts developed secondary TB disease during follow-up. Body mass index did not predict risk of TB infection but overweight household contacts had significantly decreased risk of TB disease (HR 0.48; 95% CI 0.37-0.64; p

CONCLUSIONS: High body mass index protects adults against TB disease even at levels ≥ 35 kg/m2. This protective effect does not extend to TB infection and is not seen in children.


Adolescent, Adult, Age Factors, Aged, Aged, 80 and over, Body Mass Index, Child, Child, Preschool, Contact Tracing, Disease Transmission, Infectious, Family Characteristics, Female, Humans, Incidence, Infant, Male, Middle Aged, Multivariate Analysis, Nutritional Status, Peru, Prospective Studies, Risk Factors, Tuberculosis, Pulmonary, Young Adult



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