EXPOSURE TO HOUSEHOLD COOKING FUEL AND RISK OF CATARACT FORMATION AMONG WOMEN

Abstract

Background The incidence of catracts is higher among women than men in developing countries. Risk factors for cataract include active cigarette smoking, exposure to intense sunlight, and severe diarrhea. Prior research suggests that exposure to smoke from household solid fuel may be a risk factor. Cooking and heating with solid fuels such as wood/wood-logs, dung-cake, coal and charcoal are predominant in developing countries where women are primary cooks. Methods An incidence-density casecontrol study was conducted to look at the relationship between exposure to smoke from household solid fuel and risk of cataracts among women visiting an eye hospital situated at the Nepal-India border. Cases (n = 206) were women patients, aged 35–65 years, who resided in neighboring districts in Nepal and India, and who visited the hospital for the first time with cataracts in one or both eyes. Controls (n = 203) were selected from among patients visiting the same hospital from same districts who had diagnoses of refractive error or astigmatism. Patients with a history of diabetes mellitus were excluded from both case and control groups. An interviewer-administered questionnaire included questions on education level, area of residence (urban v rural), cooking fuel, stove type, kitchen type and location, use of mosquito coil and incense, history of severe diarrhea, present food habits, smoking status, alcohol consumption, history of vitamin use, household crowding, time spent working outside in the sunlight, vaccination during childhood, house type, socio-economic status. Results Age was not a significant confounder because adjustment for age did not affect other relative risks in multivariate logistic models. In univariate analyses, the following variables were statistically significant as a risk factors for cataract: stove type (un-improved vs. improved: OR = 2.99, 95% CI: 1.93–4.63), fuel (solid vs. liquid: OR = 3.19, 95% CI: 1.99–5.1), education (illiterate vs. literate: OR =: 2.40, 95% CI: 1.44–4.00), area of residence (rural vs. urban: OR = 3.34, 95% CI: 1.76–6.25), kitchen location and ventilation (partially vs. fully: OR = 2.39 CI: 1.51–3.79), working in the sun (yes vs. no: OR = 1.51, 95% CI: 1.00–2.26). Variables such as smoking (ever vs. never: OR = 1.16, 95% CI: 0.73–1.85), history of severe diarrhea in the last five years (yes/sometime vs. no: OR = 1.22 CI: 0.81–1.82) were non-significant in the univariate analysis. In Multivariate logistic regression modeling, poor ventilation (OR: 1.89, 95% CI: 1.16–3.07), rural residency (OR: 2.15, 95% CI: 1.07–4.35), and solid fuel use with an unimproved stove (OR: 2.21, 95% CI: 1.29–3.82) were risk factors for cataracts. In our study 76% of cases and 79% of controls reportd that they did not smoke (p-value: 0.528) and only 3% of cases and controls reported that they were ex-smoker. Conclusions These preliminary analyses support the hypothesis that smokes from household solid fuel (wood, cow dung cake, crop residues, coal, coke, lignite), along with lack of ventilation in the kithcen, increases the risk of cataracts among women. In addition, rural residence seems to be a risk factor for cataracts.