Objective: 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.
Design: An observational
Setting: Several communities in
Measurements: 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).
Conclusions: 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.