Inverse correlations between serum carotenoids and respiratory morbidity and mortality: the Third National Health and Nutrition Examination Survey.

The objective was to evaluate the association between serum carotenoid levels and respiratory morbidity and mortality in a nationally representative sample of US adults. We assessed the association of serum carotenoid levels with respiratory morbidity and mortality using logistic regression and proportional hazards regression models. Meanwhile, a series of confounders were controlled in regression models and restricted cubic spline, which included age, sex, race, marriage, education, income, drinking, smoking, regular exercise, BMI, daily energy intake, vitamin E, vitamin C, fruit intake, vegetable intake, diabetes, hypertension, asthma, emphysema and chronic bronchitis. Compared with participants in the lowest tertiles, participants in the highest tertiles of serum total carotenoids, -cryptoxanthin and lutein/zeaxanthin levels had a significantly lower prevalence of emphysema (OR = 0·61, 95% CI: 0·41-0·89, OR = 0·67, 95% CI: 0·49-0·92), chronic bronchitis (OR = 0·66, 95% CI: 0·50-0·87) and asthma (Q2: OR = 0·78, 95% CI: 0·62-0·97); participants in the highest tertiles of total carotenoids, -carotene, lutein/zeaxanthin and lycopene had a lower risk of respiratory mortality (hazard ratio (HR) = 0·62, 95% CI: 0·42-0·90, HR = 0·54, 95% CI: 0·36-0·82, HR = 0·48, 95% CI: 0·33-0·71, HR = 0·66, 95% CI: 0·45-0·96) than those in the lowest tertiles. Higher serum total carotenoids and -cryptoxanthin levels is associated with decreased prevalence of emphysema and chronic bronchitis, and higher serum total carotenoids, -carotene, lutein/zeaxanthin and lycopene levels had a lower mortality of respiratory disease.