Association of Environmental Factors, Prevalence of Asthma and Respiratory Morbidity in Mumbai: Need of a Public Health Policy.

OBJECTIVE: To study the association between environmental factors, prevalence of asthma and respiratory morbidity in relation to air quality levels in a mega city. To study modifiable environmental factors in people with diagnosed asthma and increased respiratory morbidity.

METHODS: Cross sectional survey of population (N-3233) from 6 localities near air quality stations was done to study prevalence of asthma and respiratory morbidity (n-1006) followed by case control study of environmental factors by air sampling to study biological contamination.

RESULTS: Univariate analysis was performed to study effect of various risk factors. Respiratory morbidity was significantly high in areas with high SPM levels. Odd's ratio was 10.3 for wheezing, 9.16 for cough, and 12.6 for breathlessness. Presence of biological contamination of air [bacterial spores] was associated with respiratory morbidity with odds ratio of 2.2 in areas with open drainage system. Pigeon droppings were found to be the source of fungal spores and associated with respiratory symptoms with odds ratio of 1.8.

CONCLUSIONS: Respiratory morbidity significantly rises in areas with high particulate matter levels and biological contamination of air. Identification of environmental risk factors in different localities will be useful for undertaking specific mitigation measures at local level as a public health measure.