Household Fuel Use and Cardiovascular Disease Mortality: Golestan Cohort Study

Abstract

Background: Household air pollution is the third largest risk factor for global disease burden, but direct links with cardiovascular disease mortality are limited. This study aimed to evaluate the relationship between household fuel use and cardiovascular disease mortality.

Methods and results: The Golestan Cohort Study in northeastern Iran enrolled 50 045 individuals 40 to 75 years of age between 2004 and 2008 and collected data on lifetime household fuel use and other baseline exposures. Participants were followed up through 2012 with a 99% successful follow-up rate. Cox proportional hazards models were fitted to calculate hazard ratios for associations between pehen (local dung), wood, kerosene/diesel, or natural gas burning for cooking and heating and all-cause and cause-specific mortality, with adjustment for lifetime exposure to each of these fuels and potential confounders. A total of 3073 participants (6%) died during follow-up; 78% of these deaths were attributable to noncommunicable diseases, including cardiovascular, oncological, and respiratory illnesses. Adjusted 10-year hazard ratios from kerosene/diesel burning were 1.06 (95% confidence interval, 1.02-1.10) and 1.11 (95% confidence interval, 1.06-1.17) for all-cause and cardiovascular mortality, respectively. Subtype-specific analyses revealed a significant increase in ischemic heart disease (10-year hazard ratio, 1.14; 95% confidence interval, 1.06-1.21) and a trend toward cerebrovascular accident (10-year hazard ratio, 1.08; 95% confidence interval, 0.99-1.17) mortality. Stratification by sex revealed a potential signal for increased risk for all-cause and cardiovascular disease mortality among women compared with men, with similar risk for ischemic heart disease mortality.

Conclusions: Household exposure to high-pollution fuels was associated with increased risk for all-cause and cardiovascular disease mortality. Replicating these results worldwide would support efforts to reduce such exposures.

Keywords: air pollution; epidemiology; heart diseases; mortality; stroke.

Figure 1. Cox proportional hazards models for increasing levels of kerosene/diesel exposure

Hazard ratios are on a logarithmic scale for all-cause, total CVD, ischemic heart disease, and cerebrovascular accident related mortality by increasing lifetime exposure to kerosene/diesel burning (p for trend ≤ 0.022 for all). Reference groups include those with 0 years of exposure. Cox proportional hazards models were adjusted for age at enrollment, sex, rural living, socioeconomic status, education level, Turkmen ancestry, physical activity, body mass index, tobacco use, alcohol use, opiate use, self-reported diabetes mellitus, hypertension, and ischemic heart disease, and total lifetime use of other fuels.