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

BackgroundCurrent 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 body mass index (BMI) and tuberculosis risk. MethodsWe used a continuous risk framework to consider the population-level implications of BMI distributions for tuberculosis incidence for those aged [&ge;]15 years. We generated BMI distributions for each country, sex, and age group applying a bilinear model for the logarithmic relative risk of tuberculosis incidence at different BMI values. We assessed the impact of eliminating moderate/severe undernutrition (BMI<17kg/m2) or all undernutrition (BMI<18.5kg/m2) on tuberculosis incidence by constructing counterfactual BMI distributions that redistributed those with low BMI to higher BMI, proportional to the remaining density. FindingsWe estimated that eliminating moderate/severe undernutrition would avert 1.4 million (95%UI, 1.1-1.7) tuberculosis episodes globally, representing 16.8% (14.3-19.2) of global adult incidence, while eliminating all undernutrition would avert 2.3 million (1.8-2.7) episodes, a reduction of 26.5% (23.2-29.8). The largest proportional reductions in tuberculosis incidence could be achieved by eliminating undernutrition in the African, South-East Asian, and Eastern Mediterranean regions; females; and adolescent or elderly adults. InterpretationOver a quarter of global tuberculosis incidence in adults would be averted by eliminating undernutrition, approximately three times higher than current estimates. These findings highlight the urgent need to scale up population-level nutritional interventions, which may have myriad social and health benefits beyond tuberculosis, alongside research to determine optimal implementation strategies and impacts. FundingNo specific funding