Household Fuel Use and Kidney Disease-Related Mortality: The Golestan Cohort Study.

BACKGROUND: A large proportion of the global population uses solid fuels for household purposes, and limited evidence from previous studies suggests that it might be associated with reduced renal function. OBJECTIVES: To investigate the association between household use of different types of fuels and kidney disease-related mortality. METHODS: We analyzed data from the Golestan Cohort Study, a population-based prospective cohort study conducted in northeastern Iran, with 50 045 individuals aged 40-75 years enrolled in the period 2004-2008 and followed through April 2023. Information about household fuel use was collected using validated questionnaires. We estimated adjusted hazard ratios (HRs) and corresponding 95% confidence intervals (CIs) using Cox proportional hazards models. The outcome of interest was death due to any kidney disease, excluding kidney cancer (ICD-10 codes: N00-N19 and N25-N29). RESULTS: During 724,063.62 person-years of follow-up, 262 participants died due to kidney disease. The risk of kidney disease-related mortality was higher with increasing duration of biomass use for cooking or house heating (HR for every 10-year increase: 1.20; 95% CI: 1.04-1.37), while it was not associated with increased duration of using kerosene (10-y HR: 1.09; 95% CI: 0.95-1.24) or gas (10-y HR: 1.00; 95% CI: 0.86-1.16). Estimates for lifetime duration of fuel burning for both cooking and house heating (exclusive fuel use) did not differ according to whether used heating stoves were chimney-equipped or not for kerosene, while they differed for biomass (10-y HR, chimney-equipped: 1.06 [95% CI: 0.95-1.18]; 10-y HR, not chimney-equipped: 1.19 [95% CI: 1.06-1.34]; P difference = 0.025). DISCUSSION: The findings of our study suggest that burning biomass for household purposes under poor ventilating conditions is associated with kidney disease-related mortality.