The relation of dietary patterns to adult lung function and chronic obstructive pulmonary disease.

Previous studies of diet and lung function have focused on associations with individual nutrients and foods, and not dietary patterns.The relationships between dietary patterns and lung function and spirometrically defined chronic obstructive pulmonary disease (COPD) were investigated in 1,551 males and 1,391 females in Hertfordshire, UK. Dietary information was obtained by food frequency questionnaire and dietary patterns were identified using principal components analysis.Using regression analysis, after controlling for confounders, a "prudent" pattern (high consumption of fruit, vegetables, oily fish and wholemeal cereals) was positively associated with Forced Expiratory Volume in one second (FEV1) (P trend <0.001 in men, 0.008 in females) (difference in FEV1 between top and bottom quintiles of pattern score, 0.18 litres (95% CI: 0.08 to 0.28) in men, 0.08 litres (-0.00 to 0.16) in females). This pattern was also positively associated with Forced Vital Capacity (FVC) in both sexes. Males with a higher "prudent" pattern score had a higher FEV1/FVC (P trend 0.002) and a lower prevalence of COPD (odds ratio comparing top versus bottom quintile, 0.46 (0.26 to 0.81), P trend 0.012). Associations in males were stronger in smokers than non-smokers (P interaction for FEV1/FVC 0.002).A "prudent" dietary pattern may protect against impaired lung function and COPD, especially in male smokers.