Figure 3.
Mean values of adjusted FEV1 measurements across quintiles of vitamin A, carotene and vitamin C intake (energy adjusted) in subjects with COPD. Adjusted for age, body mass index, energy intake, number of comorbid diseases, alcohol consumption, place of residence, household income and education level. P values were determined using tests for linear trends across increasing quintiles (means) of antioxidant vitamin intake. COPD, chronic obstructive pulmonary disease; FEV1, forced expiratory volume in 1 s.