A field study on follow up at 10 years of prevalence of chronic obstructive pulmonary disease & peak expiratory flow rate.

In view of the paucity of follow-up field studies on patients of chronic obstructive pulmonary disease (COPD) with respect to smoking habits and lung function assessment, we undertook re-evaluation of COPD subjects 10 yr later. Of 2825 urban and 1556 rural subjects studied earlier between 1977-80, we re-examined 846 (29.9%) and 629 (40.4%) subjects respectively in 1990. A questionnaire was filled and peak expiratory flow rate (PEFR) was measured in each subject. Symptomatic subjects were grouped into chronic bronchitis, simple (CB, S) and obstructive (CB, AO). The overall prevalence of COPD was 5.0 per cent in male and 2.8 per cent in female subjects. Prevalence of both CB, S and CB, AO were higher in the smokers. In the non-smokers, CB, AO prevalence was similar in the two sexes, but CB, S was commoner in rural than urban women. This simple, hypersecretory disorder was attributed to their exposure to biomass fuel combustion. The fall in PEFR, was significantly higher in smokers than nonsmokers, and more so in the symptomatic subjects with CB, AO. It was concluded that though the overall trend of prevalence of COPD in different groups did not change over the period, those with an initial airways obstruction had deteriorated significantly more than those with normal initial PEFR.