Factors associated with serum/plasma concentrations of vitamins A, C, E and carotenoids in older people throughout Europe: the EUREYE study

To report on plasma/serum levels of antioxidant vitamin and carotenoids in older adults resident in multiple countries in Europe and examine relationships with potential modifiers. Population-based cross-sectional European Eye Study in 7 centres from northern to southern Europe. In total, 4,133 participants aged 65 years or over, collected by random sampling, were recruited. Questionnaires relating to diet, lifestyle and medical history were administered. Non-fasting blood samples were analysed in a single laboratory for vitamins A, C and E and a panel of carotenoids. Associations were analysed by bootstrapped multivariable regression analysis. Centre and season influenced the serum and plasma concentrations of all antioxidant vitamins and carotenoids. Gender, BMI, smoking, age, education, alcohol consumption and supplement use were also significantly associated with some, but not all, of the antioxidant vitamins and carotenoids examined. The proportion of variance explained ranged from 4.8 % for retinol to 25.2 % for zeaxanthin. In older people, antioxidant vitamin and carotenoid status varies by centre and season, but is also associated with other behavioural and lifestyle variables. Studies aiming to demonstrate an association between antioxidant vitamins and carotenoid status and chronic disease risk should consider these potential confounders.