Association of indoor air pollution with acute lower respiratory tract infections in children under 5 years of age

Background: Indoor air pollution is an important risk factor for acute lower respiratory tract infections (ALRTI) in developing countries. Aim: To determine the relationship of indoor air pollution with ALRTI in children under 5 years of age. Methods: A prospective, case-control study of risk factors, particularly indoor air pollution, for developing ALRTI in children under 5 years of age was conducted in Udupi District Hospital. The WHO definition of ALRTI was used. Healthy children attending immunisation services were enrolled as controls. Data pertaining to important factors causing indoor air pollution such as cooking fuel other than liquid petroleum gas (LPG) and passive smoking were collected along with potential socio-demographic factors and nutrition in both groups and analysed. Results: A total of 202 children including 101 cases and 101 controls were studied. The proportions of infants (1-12 months) among cases and controls were 62.4% and 71.3%, respectively. Of those with ALRTI, 24.8% had pneumonia, 45.5% had severe pneumonia and 29.7% had very severe disease. Exposure to passive smoking was not associated with ALRTI. Cooking fuel other than LPG was significantly associated with ALRTI (OR 26.3, 95% CI 10.5-65.7). On logistic regression analysis of multiple risk factors, cooking fuel other than LPG emerged as a significant risk factor for developing ALRTI (adjusted OR 4.73, 95% CI 1.67-13.45) along with poor socio-economic status (adjusted OR 3.38, 95% CI 1.63-7.03). Other than LPG, the main fuels used were wood (95%), kerosene and dung and crop residues. Conclusion: Indoor air pollution caused by using cooking fuel other than LPG and socio-economic factors are significantly associated with ALRTI.