beta-carotene and Airway-Obstruction

Oxidative stress is thought to have a major role in the pathogenesis of airway obstruction. A study was undertaken to determine whether subjects with low levels of antioxidants (serum beta-carotene, alpha-carotene, vitamins A and E) would be at a higher risk of accelerated decline in forced expiratory volume in 1 second (FEV1) as their lungs would be less protected against oxidative stress.. 1194 French subjects aged 20-44 years were examined in 1992 as part of the European Community Respiratory Health Survey (ECRHS); 864 were followed up in 2000 and 535 (50% men, 40% lifelong non-smokers) had complete data for analysis.. During the 8 year study period the mean annual decrease in FEV1 (adjusted for sex, centre, baseline FEV1, age, smoking, body mass index and low density lipoprotein cholesterol) was 29.8 ml/year. The rate of decrease was lower for the subjects in tertile I of beta-carotene at baseline than for those in the two other tertiles (-36.5 v -27.6 ml/year; p = 0.004). An increase in beta-carotene between the two surveys was associated with a slower decline in FEV1. No association was observed between alpha-carotene, vitamin A, or vitamin E and FEV(1) decline. However, being a heavy smoker (> or =20 cigarettes/day) in combination with a low level of beta-carotene or vitamin E was associated with the steepest decline in FEV1 (-52.5 ml/year, p = 0.0002 and -50.1 ml/year, p = 0.010, respectively).. These results strongly suggest that beta-carotene protects against the decline in FEV1 over an 8 year period in the general population, and that beta-carotene and vitamin E are protective in heavy smokers.

Topics: Adult; Airway Obstruction; Antioxidants; beta Carotene; Body Mass Index; Carotenoids; Female; Forced Expiratory Volume; Humans; Longitudinal Studies; Male; Middle Aged; Smoking; Vitamin A; Vitamin E

Dietary antioxidants, waist circumference, and pulmonary function were measured in the Fourth Scottish MONICA cross-sectional survey of 865 men and 971 women aged 25-64 years. Waist circumference was inversely related to forced expiratory volume in the first second (FEV1) and forced vital capacity (FVC), even after adjustment for age, height, weight, working status, energy intake, and smoking variables in a multiple linear regression model (men: beta = -0.017 for FEV1 l/cm, p < 0.01 and beta = -0.008 for FVC, p = 0.04; women: beta = -0.009 for FEV1, p < 0.01 and beta = -0.007 for FVC, p = 0.01). After additional adjustment for waist circumference, estimated vitamin C and beta-carotene intakes were positively associated with lung function in men (vitamin C: beta = 0.102 for FEV1 l/mg/day, p = 0.03; beta-carotene: beta = 0.073 for FVC l/g/day, p = 0.02). Retinol and vitamin E were not significantly related to lung function for either sex. A case-control study of airway obstruction showed that waist circumference was significantly associated, while vitamin C could be protective. The study suggests that adequate intake of antioxidants and avoidance of increasing girth could help to preserve lung function.

Topics: Adult; Airway Obstruction; Anthropometry; Antioxidants; Ascorbic Acid; beta Carotene; Body Constitution; Case-Control Studies; Cross-Sectional Studies; Diet; Female; Forced Expiratory Volume; Humans; Linear Models; Male; Middle Aged; Obesity; Scotland; Vital Capacity; Vitamin A; Vitamin E