The Respiratory Health of Rural Indian Women: Does the Domestic Cooking Fuel Really Matter?

Dear Sir,

It is noteworthy that the air pollution in big cities creates headlines,but in many rural areas of the developing countries, the indoor airpollution is an even more serious health problem. The provision ofair that is safe to breathe is just as important as safe water or food.Yet many millions of people, predominantly women, in the poorand developing countries, are obliged to breathe air that is heavilypolluted with biomass emission products, which is a well-recognizedsource of acute as well as chronic morbidities that primarily affectthe lungs [1, 2]. Poverty condemns half of the humanity to cookwith solid fuels on inefficient stoves. As a cause of the ill health inthe world, indoor air pollution ranks behind only malnutrition, AIDS,tobacco, and poor water or sanitation. The smoke in homes fromthese cooking stoves is the fourth greatest risk factor for death anddisease in the world’s poorest countries, and has been linked to1.6 million deaths per year [3]. Yet the international community haslargely neglected it. This report calls for global action to fight thekiller in the kitchen – the smoke from the cooking stoves.

We conducted a community based, cross-sectional study in theRaipura village (with a total population of 7635 as per the censusof 2001) of Hingna tehsil, Nagpur district in central India, withthe objective of assessing the relationship between the type ofcooking fuel and the airway reactivity in rural Indian women whowere involved in household cooking with four different kinds ofcooking fuels; 252 used biomass, 73 used kerosene stoves, 192used Liquefied Petroleum Gas (LPG) and 243 used mixed fuels (acombination of two and more cooking fuels). The eligibility criteriafor this study were 1) age ≥ 15 years 2) the principal cook of thefamily and 3) non-smokers. The Exposure Index (EI) i.e. the averagetime per day which is spent near the fireplace multiplied by theyears of exposure, was calculated [4, 5]. The Peak Expiratory FlowRate (PEFR) was measured in litres per minute according to thestandards which were recommended by the American ThoracicSociety [6]. The observed PEFR was calculated on the basis of theage in years and the height was measured in centimetres. Whereas,the predicted values for the PEFR in females were calculated as3.310*height (cms) – 1.865*age (years) – 81.0 [7]. The airwayreactivity was defined as a PEFR of less than 80% of the predictedvalue. The data was analyzed by using the Analysis of Variance(ANOVA) and multivariate logistic regression (MLR) models byusing the statistical software, STATA version 10.1. The resultsshowed that a high prevalence of airway reactivity was found inthe biomass users [109 (43.3%)] as compared to that in the othergroups. The mean observed PEFR showed a declining trend withan increase in the age, the duration of cooking and the exposureindex in all the fuel users. The overall logistic regression model,when it was taken together, revealed that in the observationsof a total of 760 study subjects; the age, the cooking fuel andthe exposure index were significant predictors of the abnormalPEFR. Whereas no significant association was found between anabnormal PEFR and height [Table/Fig-1(a)]. However, a result of thesubgroup analysis with the type of cooking fuel revealed that inthe mixed fuel users; age [OR - 2.08, 95% Confidence Interval (CI)1.32 - 3.28, P 0.00], height (OR -1.06, 95% CI 1.00 - 1.12, P 0.02)and the exposure index (OR -2.74, 95% CI 1.68 - 4.47, P 0.00)were significant predictors of the airway reactivity. Whereas in thebiomass and the LPG users, only the exposure index was foundto be the significant predictor of the airway reactivity (P<0.05) andno significant association was found between the airway reactivityand the various predictors in the kerosene users (P>0.05) [Table/Fig-1(b)]. Thus, mixed fuel seems to be more deleterious in theimpairment of the respiratory health of the rural Indian women, afterrobustly adjusting for the confounding variables, as was evidentby a significant association of the airway reactivity with it. Similarfindings as ours were reported in studies which were carried out innorth India [4, 5]. While the precise mechanism of how the exposurecauses an impairment in the lung function is still unclear, it is knownthat the small particles and several of the other pollutants which arecontained in the indoor smoke cause inflammation of the airwaysand lungs and impair the immune response. Carbon monoxidealso causes systemic effects by reducing the oxygen-carryingcapacity of the blood. Oxidative stress may also be a component,as oxidizing radicals are present in the biomass smoke and arealso released by the inflammatory cells [1].

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