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Pulmonary function decline and 17-year total mortality: the Honolulu Heart Program
B L Rodriguez1, K Masaki, C Burchfiel
1Honolulu Heart Program, Kuakini Medical Center, HI 96817.
Insights
A faster rate of decline in forced expiratory volume in 1 second (FEV1) predicts higher total mortality in smokers. This lung function decline is a significant risk factor for death, especially in those with a history of smoking.
Area of Science:
- Pulmonary Medicine
- Epidemiology
- Gerontology
Background:
- The Honolulu Heart Program is an ongoing study of Japanese-American men.
- Forced expiratory volume in 1 second (FEV1) is a key measure of lung function.
- Understanding factors predicting mortality is crucial for public health.
Purpose of the Study:
- To investigate the association between the rate of decline in FEV1 and total mortality.
- To determine if FEV1 decline is an independent predictor of mortality in a cohort of Japanese-American men.
Main Methods:
- Longitudinal cohort study of 4,000 Japanese-American men aged 45-68.
- FEV1 measured between 1965-1974; rate of change (slope) calculated using linear regression.
- 17 years of follow-up; mortality data analyzed using Cox proportional hazards models, adjusting for covariates.
Main Results:
- A faster rate of FEV1 decline was significantly associated with increased total mortality (p < 0.0001).
- Men in the highest tertile of FEV1 decline had a 48% higher risk of death (RR=1.48, 95% CI 1.24-1.77) compared to those with the smallest change.
- The association remained significant for past smokers and across different pack-year groups, but not for never smokers.
Conclusions:
- The rate of decline in FEV1 is a significant predictor of total mortality, particularly among smokers.
- Lung function decline may serve as an early warning sign for increased mortality risk in smoking populations.
- Further research could explore mechanisms linking FEV1 decline to mortality in smokers.
Abstract:
The Honolulu Heart Program continues to follow a cohort of Japanese-American men initially aged 45-68 years, of whom 4,000 had three acceptable measurements of forced expiratory volume in 1 second (FEV1) between 1965 and 1974 and were free of cardiovascular disease and cancer. The 6-year rate of change (slope) in FEV1 was calculated using a within-person linear regression method. Men were divided into tertiles based on the rate of change in FEV1. During 17 subsequent years of follow-up, 796 deaths occurred. The tertile with the greatest rate of decline in FEV1 (mean, -61 ml/year) had the highest age-adjusted total mortality rate (17.3/1,000 person-years), followed by rates of 13.2 for the middle tertile (mean, -25 ml/year) and 11.0 for men with the smallest change in FEV1 (mean, +9 ml/year) (test for trend, p < 0.0001). Using the Cox model, comparing the tertile with the smallest change in FEV1 as a reference group with the tertile with the greatest decline in FEV1, and after adjusting for age, hypertension, smoking, body mass index, alcohol intake, diabetes mellitus, and cholesterol, the authors found the relative risk (RR) for total mortality to be 1.48 (95% confidence interval (CI) 1.24-1.77). After stratification by smoking status, this association remained significant for past smokers (RR = 1.79, 95% CI 1.31-2.14), as well as for the low, < or = 42 (RR = 1.46, 95% CI 1.05-2.03), and high, > 42 (RR = 1.56, 95% CI 1.20-2.02), pack-year groups. An increased risk was also present for current smokers (RR = 1.29), but it was of borderline significance (p = 0.08). No association was found among never smokers. These data suggest that the rate of decline in FEV1 is a predictor of total mortality among smokers.