Waiting to inhale: An exploratory review of conditions that may predispose to pulmonary hypertension and right heart failure in persons exposed to household air pollution in low- and middle-income countries

Abstract

The health effects of exposure to household air pollution are gaining international attention. While the bulk of the known mortality estimates due to these exposures are derived from respiratory conditions, there is growing evidence of adverse cardiovascular health effects. Pulmonary hypertension and right heart failure are common conditions in low- and middle-income countries whose etiology may be related to common exposures in these regions such as schistosomiasis, human immunodeficiency virus, tuberculosis infections and other causes. While little is known of the interplay between exposure to household air pollution, right heart function and such conditions, the large burden of pulmonary hypertension and right heart failure in regions where there is significant exposure to household air pollution raises the possibility of a linkage. This review is presented in three parts. First, we explore what is known about pulmonary hypertension and right heart failure in low- and middle-income countries by focusing on eight common causes thereof. We then review what is known of the impact of household air pollution on pulmonary hypertension and posit that when individuals with one of these eight common comorbidities are exposed to household air pollution they may be predisposed to develop pulmonary hypertension or right heart failure. Lastly, we posit that there may be a direct link between exposure to household air pollution and right heart failure independent of pre-existing conditions which merits further investigation. Our overall aim is to highlight the multifactorial nature of these complex relationships and offer avenues for research in this expanding field of study.

Keywords: household air pollution; low- and middle-income countries; pulmonary hypertension; right heart failure.

Figure

Factors contributing to the burden of pulmonary hypertension and right heart failure in low- and middle-income countries. Common comorbidities found in low- and middle-income countries LMICs (brown boxes) each can predispose individuals to developing pulmonary hypertension (PH) and subsequent right heart failure (RHF) (blue arrows). Household air pollution (HAP) (grey triangle) may also cause PH and RHF directly (grey arrow). The high burden of PH/RHF in LMICs may be due to a background predisposition related to the presence of these comorbidities and subsequent exposure to HAP (red arrow).