Ventilatory function, height, and mortality among lifelong non-smokers

Abstract

Study objective: The aims were to determine the relationship between spirometric indices and mortality among lifelong non-smokers, and to investigate whether the association of short stature with increased risk of death is explained by reduced levels of ventilatory function in shorter men.

Design: The study was a nested (within cohort) case-control analysis of an 18 year prospective study of mortality.

Subjects: Participants were 3452 male civil servants aged 40-64 years at entry who denied ever having smoked tobacco.

Measurements and main results: 408 men who died were matched to 2874 controls of the same age and height. Reduced one second forced expiratory volume (FEV1) was associated with mortality from non-respiratory causes (rate ratio per litre decrease = 1.44, 95% confidence interval 1.196-1.73). The ratio of FEV1 to forced vital capacity was a weak predictor of mortality. Among 397 case-control sets matched for age and FEV1, mortality was unrelated to height. Comparing mortality differentials across age adjusted tertiles of each risk factor, height adjusted FEV1 was a stronger predictor of death than height, body mass index, or plasma cholesterol. FEV1 adjusted for age but not for height was almost as strong a predictor as systolic blood pressure.

Conclusions: The determinants of ventilatory function in lifelong non-smokers may include causes of premature death. FEV1 may be a more sensitive indicator than height of early life influences upon mortality.