Environmental-demographic determinants associated with tuberculosis prevalence in seven African countries: an aggregated dataset analysis

TL;DR

This study finds that environmental and demographic factors like latitude, population density, and altitude are linked to higher or lower tuberculosis prevalence in seven African countries.

Contribution

The study uses an individual participant dataset from seven African countries to identify environmental-demographic determinants of tuberculosis prevalence.

Findings

Higher tuberculosis prevalence is associated with living at latitude 7.6–14.6°, higher population density, and urban districts.

Lower tuberculosis prevalence is associated with higher altitude, moderate precipitation, and higher temperature.

No significant associations were found with fine particulate matter, solar radiation, or the International Wealth Index.

Abstract

Knowledge about environmental and demographic determinants of tuberculosis is largely limited to studies with ecological designs. We explored the association between these determinants and tuberculosis prevalence in an individual participant dataset aggregated across seven African countries.

Data of nationally representative tuberculosis prevalence surveys (2012–2019) from highly endemic countries were supplemented with publicly accessible data at district level. Associations between individual-level diagnosis of bacteriologically confirmed tuberculosis and district-level environmental-demographic variables were investigated in generalised linear mixed-effects models accounting for the multi-level structure of the data.

Of 322,615 participants aged ≥15 years across 400 districts, 976 were newly diagnosed with tuberculosis (prevalence 183–638/100,000 across the countries). Living at latitude 7.6–14.6° (adjusted odds ratio, aOR 2.07, 95% confidence interval, 95% CI 1.48–2.90) or in higher population density (aOR 1.07 per percent increase in mean population density, 1.01–1.13), or urban districts (aOR 1.31, 1.11–1.54) were independently associated with higher prevalence. Living in distsricts above 900 m altitude (aOR 0.52, 0.32–0.84), with 50–100 mm precipitation (aOR 0.62, 0.46–0.84), or at higher temperature (aOR 0.93 per degree Celsius, 0.88–0.98) was independently associated with lower tuberculosis prevalence. No significant associations were observed with fine particulate matter (aOR 1.04, 0.70–1.54 for 20–40 μg/m3, 0.82, 0.44–1.53 for >40 μg/m3), solar radiation (aOR 1.04, 0.93–1.15) or International Wealth Index (aOR 1.01 (1.00–1.02).

Our results suggest that in high-burden African countries, some of the variation in tuberculosis prevalence can be explained by environmental and demographic factors that merit further investigation.

Mr Willem Bakhuys Roozeboom Foundation.

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