The social and structural determinants of tuberculosis incidence trends in 116 countries from 2005-2015: an ecological study

<b>Objective:</b> To understand key social and structural determinants of health that influenced global tuberculosis (TB) incidence trends during the Millennium Development Goal (MDG) era which may help accelerate future declines. <b>Methods:</b> We estimated associations between TB incidence rates and 17 indicators of structural and intermediary social determinants of health following the definitions of the Commission on Social Determinants of Health in a longitudinal ecological design. A stepwise regression analysis using fixed effects Poisson models was conducted separately in high-income countries (HICs) and low- and middle-income countries (LMICs). <b>Results:</b> The sample included 19 HICs and 97 LMICs. A decline in TB incidence rate was observed in 108 out of 116 countries with a mean decline of 12.96% over follow up. In LMICs, within country improvements in health expenditure per capita (IRR 0.9999, 95% CIs: 0.9998-0.9999) and Human Development Index (IRR 0.9907, 95% CIs: 0.9851-0.9964) were associated with declines in TB incidence rates. Within country increases in TB case detection rate (IRR 1.0014, 95% CIs: 1.0002-1.0026), prevalence of undernourishment (IRR 1.0025, 95% CIs: 1.0008-1.0042) and prevalence of diabetes (IRR 1.0069, 95% CIs: 1.0029-1.011) were associated with increases in TB incidence rate. In HICs, there was no evidence that variation in either structural or intermediary social factors was associated with TB incidence trends. <b>Conclusion:</b> Action on health investments, broader human development and diabetes control may assist in accelerating future declines in TB incidence in LMICs and contribute to achieving the End TB Strategy goals.