Lung Function as a Risk Factor for Subarachnoid Hemorrhage
A Prospective Cohort Study
Background and Purpose—The etiology of subarachnoid hemorrhage (SAH) is poorly understood. Reduced lung function, expressed as low forced expiratory volume in 1 second (FEV1) and low forced vital capacity (FVC), is a predictor of cardiovascular disease, but whether reduced lung function is a risk factor for SAH is not known. The association between lung function and incidence of SAH was investigated in a prospective cohort study.
Methods—Between 1974 and 1992, 20 534 men and 7237 women (mean age, 44 years) were examined in a health screening program including spirometry. The incidence of SAH was studied during a mean follow-up of 26 years in relation to age- and height-standardized FEV1, FVC, and FEV1/FVC.
Results—One hundred forty-five subjects had a SAH (18.3 per 100 000 person-years in men and 26.5 per 100 000 person-years in women). The hazard ratio for SAH in the lowest compared to the highest quartile of FEV1 and FEV1/FVC was 2.24 (95% CI, 1.32–3.81; P for trend=0.014) and 1.92 (95% CI, 1.14–3.23; P for trend=0.003), respectively, after adjustment for several confounding factors including smoking and hypertension. The results persisted when analysis was restricted to nonsmokers. FVC showed no significant association with incidence of SAH.
Conclusions—Baseline lung function, expressed as low FEV1 or FEV1/FVC, is a risk factor for SAH, independently of smoking.
- forced expiratory volume
- forced vital capacity
- prospective study
- subarachnoid hemorrhage
- Received March 22, 2012.
- Revision received July 11, 2012.
- Accepted July 12, 2012.
- © 2012 American Heart Association, Inc.