Eric Coker, MS, PhD

GHES U.S. Fellow 2017-2018

Fellowship Site: Makerere University, Kampala, Uganda
US Institution: University of California, Berkeley

Project Title: Assessment of Household and Area-level Environmental Risk Factors for Secondary Tuberculosis among Homes with Index Cases

The social determinants of health have long been considered important drivers of Tuberculosis (TB) risk. Evidence suggests that certain environmental exposures that are related to the social determinants, especially indoor air pollution (IAP) and more recently outdoor air pollution, may be important risk factors for TB transmission. However, the precise environmental factors contributing to TB transmission in sub-Saharan Africa, including Uganda, are largely unknown. Uganda is considered by the World Health Organization to be a high TB burden country. Despite the decline in Uganda’s TB incidence over time, this decline has plateaued all while poor outdoor and indoor air quality persist in urban settings. It is therefore critical to characterize the environmental factors contributing to Uganda’s TB transmission risks.

To address the environmental factors potentially influencing the TB burden in Uganda, a short-term project will encompass primary data collection in the field for TB contact cases, and household-level and neighborhood-level environmental indicator data, while a second project will encompass TB surveillance and outdoor air quality data collection efforts to benefit a later population-based study.

A nested cross-sectional study will investigate the association between indicators of IAP and area-level outdoor air pollution and TB transmission between active TB index cases and their household contacts. This study will leverage the current infrastructure and study population from an NIH R01-funded household TB contact tracing study underway in Kampala, Uganda. We will survey the homes of microbiologically confirmed TB index patients to ascertain the frequency of co-prevalentTB cases among contacts. We will survey each household for factors previously shown to influence IAP levels including: the cookstove fuel-type; the location and frequency of cookstove use; the presence and frequency of use of windows for ventilation during cookstove use; CO2 decay measure of ventilation; and the number of rooms and occupants. In addition to household IAP indicators, we will also use available spatial and land use data (e.g. GPS coordinates of index case homes, land classification system, and remote sensing) to examine area-level outdoor air pollution indicators in Kampala potentially related to TB contact cases.