Decline in lung function and mortality: the Busselton Health Study

Area of Science:

• Pulmonary Medicine
• Epidemiology
• Public Health

Background:

• Lung function, specifically forced expiratory volume in 1 second (FEV1), is directly linked to mortality rates.
• Accelerated decline in FEV1 over time may serve as an independent predictor of mortality.
• Understanding factors influencing lung function decline is crucial for public health strategies.

Purpose of the Study:

• To investigate the association between the rate of FEV1 decline and mortality within a community-based cohort.
• To determine if FEV1 decline is an independent predictor of mortality, separate from average FEV1 levels and cardiovascular risk factors.

Main Methods:

• A cohort of 1,691 individuals (751 men, 940 women) from five cross-sectional studies (1969-1981) with three lung function assessments over six years was analyzed.
• Average FEV1 and FEV1 decline (litre/year) were calculated for each participant.
• Mortality follow-up was conducted until December 1995, with causes of death classified using ICD-9 codes.

Main Results:

• The average FEV1 decline was 0.04 L/year in men and 0.03 L/year in women.
• Lower average FEV1 was significantly associated with all-cause and cardiovascular disease mortality in both sexes.
• In women, a 0.05 L/year increase in FEV1 decline raised all-cause mortality risk by 23% (HR 1.23, 95% CI 1.06-1.44), adjusting for covariates.
• In men, a similar increase in FEV1 decline showed a smaller, but significant, association with all-cause mortality (HR 1.19, 95% CI 0.99-1.21).

Conclusions:

• Decline in lung function, as measured by FEV1, is a significant predictor of mortality.
• This association is independent of an individual's average FEV1 level.
• FEV1 decline is an independent risk factor for mortality, even when controlling for cardiovascular disease risk factors.