Transition of cooking fuel types and mortality risk in China, 1991-2015

The decision for household cooking fuel choice is a complex and multi-dimensional process. This study aims to: 1) examine the trend of cooking fuel types during past decades; and 2) examine the association between switching from polluting to clean fuels for cooking and mortality risk.

This analysis included data on 39,359 participants from 9 waves of the China Health and Nutrition Survey (CHNS) (1991-2015). Participants with consistent polluting fuel use and with the polluting-to-clean transition were identified. Generalized estimating equations were used to examine the trend of clean fuel use from 1991 to 2015. Propensity score matching was used to address the data imbalance and confounding factors and Cox proportional hazards models were used to estimate the association.

We found an increasing trend of clean fuel use after adjusting for potential confounders in the full sample (OR = 56.89, 95 % CI: 48.17, 67.19), which appeared to be more pronounced for those in rural areas and with low socioeconomic status. Switching from polluting to clean fuels was associated with a 75 % lower risk of mortality (HR = 0.25, 95 % CI: 0.11, 0.54). These associations became more pronounced during the lag period from 9 to 15 years.

The transition from polluting to clean cooking fuels reduced excess deaths in China, particularly over a long period. Our findings support the increasing implementation of clean fuels and call for more efforts to improve its universal service, especially in rural and low socioeconomic status areas, to minimize health inequality.