Baseline cigarette smoking and dusty job exposure associations with COPD and asthma symptoms in theVitamin D and Omega-3 Trial (VITAL)

摘要

Background Chronic obstructive pulmonary disease (COPD) is a major cause of morbidity and mortality worldwide. The Vitamin D and Omega-3 Trial (VITAL) is randomizing ＞22,000 U.S. adults ＞50 years of age to examine vitamin D and fish oil supplementation effects on cancer and cardiovascular disease development. Lung VITAL will investigate supplement effects on COPD exacerbation, asthma control, and level of lung function. Aims To examine the pre-randomization cross-sectional relationship of cigarette smoking and dusty jobs on COPD manifestations and pulmonary function in Lung VITAL participants. Methods A subset of 5848 study participants enriched for respiratory symptoms completed a baseline respiratory questionnaire. We compared rates of chronic cough, chronic phlegm, dyspnea (Modified Medical Research Council Dyspnea Scale),and wheezing between exposed and non-exposed subjects and used logistic models to adjust for subject demographics. Juniper asthma control score was calculated. For 620 subjects, adjusting for age, height, BMI, sex, and ethnicity/race, we used linear models to examine effects of smoking and dusty jobs on FEV1. Results Former and current smoking rates were 45% and 10% (average pack-years=24.2); 4% had dusty jobs. Wheeze more than once a week, chronic cough, chronic phlegm, dyspnea, and asthma symptoms increased from never to former to current smoking (e.g., wheeze rates were 11%, 13%, 31%) and with dusty jobs (wheeze: 22% vs. 14%, chronic cough: 33% vs. 24%). Compared to no smoking, ＞30 pack-years of smoking was associated with a decrease of 217 ml (95% CI: 88-346) in FEV1. The odds of any dyspnea were 26% (95% CI: 7-48%) higher for 10-30 pack-years, and 130% (95% CI: 96-170%) higher for ＞30 pack-years, compared to no smoking, and 60% (95% CI: 22-110%) higher for subjects exposed to dust. Conclusion In this vitamin D and fish oil supplementation trial, baseline dyspnea, wheeze and lung function are adversely influenced not only by smoking, but also by occupation. This work is funded by NHLBI (R01 101932).