Global, regional, and national estimates of tuberculosis incidence averted by eliminating undernutrition in adults: a modelling study.

BACKGROUND

Current efforts to reduce global tuberculosis incidence have proved insufficient, highlighting that urgent action is needed to address underlying modifiable risk factors such as undernutrition. We aimed to estimate the global impact of eliminating undernutrition on tuberculosis incidence among adults, accounting for varying nutritional status by country, sex, and age, in addition to incorporating the continuous, non-linear relationship between BMI and tuberculosis risk.

METHODS

For this modelling study, we used a continuous risk framework to consider the population-level implications of BMI distributions for tuberculosis incidence in adults aged 15 years or older in 2023. We generated BMI distributions for each country, sex, and age group, and applied a bilinear model for the logarithmic relative risk of tuberculosis incidence at different BMI values. We assessed the impact of eliminating moderate-to-severe undernutrition (BMI <17 kg/m2) or all undernutrition (BMI <18·5 kg/m2) on tuberculosis incidence by constructing counterfactual BMI distributions that redistributed those with low BMI to high BMI, proportional to the remaining density.

FINDINGS: We estimated that eliminating moderate-to-severe undernutrition could avert 1·4 million (95% uncertainty interval 1·1-1·7) tuberculosis episodes globally, representing 14·6% (12·6-16·6) of global adult incidence in 2023, while eliminating all undernutrition could avert 2·3 million (1·8-2·7) episodes, representing a reduction in global tuberculosis incidence of 23·7% (20·9-26·5). The largest proportional reductions in tuberculosis incidence could be achieved by eliminating undernutrition in the WHO African, South-East Asia, and Eastern Mediterranean regions; in females; and in adolescents or older adults.

INTERPRETATION: Almost a quarter of global tuberculosis incidence in adults could be averted by eliminating undernutrition, approximately two-and-a-half times higher than current estimates. These findings highlight the urgent need to scale up population-level nutritional interventions, which could have myriad social and health benefits beyond tuberculosis, alongside research to establish optimal implementation strategies and impacts.

FUNDING: None.