Acute Wood Smoke Exposure and Heart Rate Variability among Rural Mexican Women

Abstract

Background. Previous studies have shown an association between air pollution and cardiovascular diseases. But little is known about the cardiovascular effects of indoor air pollution due to household use of solid fuels. Aims. In this study, we investigated the association of fine particulate matter (PM2.5) and carbon monoxide (CO) on heart rate variability (HRV) in women using an open fire or an efficient wood stove (Patsari). Methods. Fifty three women of highlands Michoacan in Mexico using firewood for cooking participated in this study. Twenty-four hours ambulatory electrocardiographic recording with simultaneous continuous personal CO concentration monitoring and micro-environmental monitoring of particles PM2.5 in the kitchens were performed without affecting the daily activities of the participating women. Spectral analysis measures of Heart Rate Variability (HRV) were calculated for 30-min segments. The association between HRV and pollutants levels was analysed using linear mixed models. Results. After adjusting for relevant covariates, we found a significant decrease in the high-frequencies (beta = -0.024, 95% CI -0.041, -0.006) and a tendency towards the reduction for the low frequencies (beta = -0.011, 95% CI -0.025, 0.003) for each ppm of carbon monoxide. We found an association with PM2.5 in the same direction but not significant. Conclusions. The results of this study suggest an association between exposure to carbon monoxide and significant alterations in cardiac autonomic function. These results extend our understanding of the adverse health effects of the CO and fine particulate matter presents in the wood smoke.