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Corneal Physician Bulletin: Using Solid Fuel Long Term to Cook Raises Risk of Eye Conditions

           Cooking with solid fuel (e.g., coal or wood) long-term is linked with higher risks of conjunctiva disorders, cataracts, sclera, cornea, iris, and ciliary body disorders (DSCICs), and cases of glaucoma, reports PLoS One1
            Specifically, compared with those who used clean fuel (e.g., electricity or gas), solid fuel users had adjusted odds ratios (ORs) of 1.32 (1.07 to 1.37, p < 0.001) for conjunctiva disorders, 1.17 (1.08 to 1.26, p < 0.001) for cataracts, 1.35 (1.10 to 1.66, p = 0.0046) for DSCICs, and 0.95 (0.76 to 1.18, p = 0.62) for glaucoma.
            Additionally, switching from solid to clean fuels was linked with less increased risks (over long-term clean fuel users), with adjusted ORs of 1.21 (1.07 to 1.37, p < 0.001), 1.05 (0.98 to 1.12, p = 0.17), and 1.21 (0.97 to 1.50, p = 0.088) for conjunctiva disorders, cataracts, and DSCICs, respectively.
            What’s more, the adjusted ORs for the eye conditions were “broadly similar” in those who used solid fuel, despite ventilation status. 
            The researchers arrived at these findings after drafting 512,715 adults, ages 30 to 79, from 10 areas in China from 2004 to 2008 and asking them via questionnaire their cooking frequency and primary fuel types for doing so. Amid median (10.1 [9.2 to 11.1]) years of follow-up, electronic linkages to national health insurance databases revealed 4,877 cases of conjunctiva disorders, 13,408 cataracts, 1,583 of DSCICs, and 1,534 incidences of glaucoma. The researchers adjusted for confounding factors, such as age at baseline, alcohol use, birth cohort, body mass index, cookstove ventilation, education, environmental tobacco smoke, heating fuel exposure, length of recall period, occupation, prevalent diabetes, self-reported general health, sex, smoking, and study area.
            As there is narrow evidence from cohort studies on the links between using solid fuels and major eye diseases, the researchers sought to perform this study. They note that over 3.5 billion individuals worldwide are exposed to household air pollution that comes from solid fuel use. 
            The study’s researchers say the main limitations of this study were a lack of baseline eye disease assessment, the use of self-reported cooking frequency and fuel types, the risk of bias due to delayed diagnosis (especially for cataracts) and potential residual confounding from unmeasured factors (e.g., sunlight exposure). CP

1. Chan KH, Yan M, Bennett DA, et al. Long-term solid fuel use and risks of major eye diseases in China: A population-based cohort study of 486,532 adults. Published: July 29, 2021. https://doi.org/10.1371/journal.pmed.1003716