Restricted spirometry in the Burden of Lung Disease Study

BACKGROUND: The presence of restrictive lung disease has classically required the measure of total lung capacity to document 'true' restriction, which has limited its detection in large population-based studies.METHODS: We used spirometric data to classify people with restricted spirometry (forced expiratory volume in 1 second [FEV1]/forced vital capacity ≥ 0.70 and FEV1 < 80% predicted) in the Burden of Lung Disease (BOLD) Study and determined the relation between this finding and demographic factors and the presence of chronic diseases, including diabetes mellitus, hypertension and cardiovascular disease.RESULTS: Overall, we found that 11.7% of men (546/4664) and 16.4% of women (836/5098) had restricted spirometry. Prevalence varied widely by site, from a low of 4.2% among males in Sydney, Australia, to a high of 48.7% among females in Manila, The Philippines. Compared to people with normal lung function, those with restricted spirometry had a higher prevalence of diabetes (12.2% vs. 4.6%), heart disease (15.0% vs. 7.7%) and hypertension (38.8% vs. 22.8%).CONCLUSIONS: Restricted spirometry is a common finding in population studies. Additional research is needed to better define and describe the mechanisms that lead to restricted spirometry and potential interventions.