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The epidemiology and clinical management of chronic obstructive pulmonary disease in Singapore

Risk factors for COPD include host factors and exposure. The known host factors associated with COPD are a1AT deficiency, airway hyperresponsiveness and maximal lung growth. External factors include cigarette smoking, occupational dusts, indoor/outdoor air pollution, infections and socioeconomic status. At present, cigarette smoking, heavy exposure to occupational dusts and indoor air pollution and a hereditary deficiency of a1AT deficiency are the only risk factors that are considered capable of causing COPD. In some developing countries, a high prevalence of chronic cough and sputum have been attributed to the heavy exposures to indoor air pollution that are experienced in smoky, unventilated dwellings. This is unlikely to be a contributory factor in Singapore. The role of occupational dust exposure in COPD in Singapore is also small, as reflected by the low incidence of pneumoconiosis. The association of a1AT deficiency with COPD has not been reported in Singapore. The main risk factor for COPD is chronic exposure to tobacco smoke.