Respiratory symptoms and pulmonary function in an elderly nonsmoking population

To examine risk factors for chronic airway disease (CAD) in elderly nonsmokers, as determined by pulmonary function tests (PFTs), and to correlate reported respiratory symptoms with PFT measures.

An observational survey.

Several communities in California.

Exposures and respiratory history were assessed by standardized questionnaire. PFTs were performed and prediction equations derived.

Significant risk factors for obstruction on PFTs in multiple logistic regression included reported environmental tobacco smoke (ETS) exposure (relative risk [RR]=1.44), parental CAD or hay fever (RR=1.47), history of childhood respiratory illness (RR=2.15), increasing age, and male sex. The number of years of past smoking was of borderline significance (RR=1.29 for 10 years of smoking; p=0.06). The prevalence of obstruction on PFTs was 24.9% in those with definite symptomatic CAD, compared with 7.5% in those with no symptoms of CAD. The prevalence of obstruction was 36.0% among those with asthma and 70.6% among those with emphysema. Also, symptomatic CAD correlated with reduction in lung function by analysis of covariance. The mean percent predicted FEV1 adjusted for covariates was 90.6% in persons with definite symptoms of CAD, compared with 97.8% in those without it (p < 0.001).

Age, sex, parental history, childhood respiratory illness, and reported ETS exposures were significant risk factors for obstruction on PFTs. Self-reported respiratory symptoms also correlated significantly with PFTs.