Respiratory symptoms and chronic obstructive pulmonary disease : prevalence and risk factors in a predominantly low-income urban area of Cape Town, South Africa

Includes bibliographical references.The continuing worldwide increase in the incidence of chronic obstructive pulmonary disease (COPD) has led to international initiatives to improve surveillance and identify preventable risk factors for this and related chronic lung diseases. The studies reported here aimed to examine the prevalence and risk factors for respiratory symptoms and COPD; to introduce and test surveillance methodologies; and to inform treatment and control measures for this disease. The Lung Health Survey 2002 sampled 3512 individuals aged ≥ 15 years from an urban population of 36,334 in the predominantly low-income area of Ravensmead and Uitsig, Cape Town, South Africa. Information on respiratory symptoms, risk factors and healthcare utilisation was collected using a respiratory questionnaire which included questions that had been validated elsewhere. In 2005, a subsample of 960 persons aged ≥ 40 years participated in the Burden of Obstructive Lung Disease (BOLD) study comprised of a questionnaire and pre and postbronchodilator spirometry, in order to assess the prevalence of COPD. A high prevalence of respiratory symptoms of 38.3% was reported. Tobacco smoking showed a consistent positive association with chronic bronchitis, wheeze, dyspnoea and cough. Strong associations with cannabis smoking, pulmonary tuberculosis, occupational exposures and low socioeconomic status were found. The association of cannabis smoking with respiratory symptoms suggest that it may be a risk factor for COPD. The BOLD study revealed an exceptionally high prevalence of COPD in both men and women aged 40 years and older (29% and 20%, respectively) reflecting the very high prevalence of smoking in both sexes in the test area. The majority of those affected had moderate to severe disease, that is, symptoms with spirometric impairment (GOLD Stage II and higher). Even non-smoking women had a comparatively high prevalence of CO PO (12.6%), attributable to other risk factors such as tuberculosis and occupational exposures. Previous pulmonary tuberculosis was shown to be a strong predictor of COPD, which warrants further study. Review of healthcare utilisation confirmed significant under-recognition and under-treatment within local health services. These results confirm the need to prioritise preventative and treatment strategies for obstructive lung disease in South Africa