Objective: To describe 10 year trends and individual changes in food habits of Danish men and women in relation to dietary recommendations using data from both a cohort and a repeated cross-sectional study, and to examine whether the two sampling methods give similar results.
Design: Baseline data were collected in 1982-1984 and respectively repeated measurements for cohort and cross-sectional changes in food habits.
Setting: The County of Copenhagen, Denmark.
Subjects: Men and women aged 30-70y in 1982-1984, 1986-1988 and 1992-1994. The trend analyses included 3785 subjects for cohort and 7316 for cross-sectional study, respectively. Longitudinal changes were studied among 2430 individuals with food data from all three examinations.
Methods: Food intakes were estimated using a short food frequency questionnaire.
Results: During the study period both men and women reported a decreased intake frequency of animal and vegetable fats, milk, eggs, meat products, white bread and potatoes, while they had increased intakes of low-fat margarine, fruit, raw vegetables, coarse breads, oatmeal, pasta, rice, cakes and candy. In both men and women the decrease in the consumption frequency of, white bread and potatoes, and the increase in pasta, and candy, were higher in the younger than in the older age group. In contrast, the increased consumption frequency of coarse breads, and oatmeal were most pronounced in the older age groups. For most foods the cohort and the repeated cross-sectional surveys gave similar results.
Conclusions: From 1982 through 1994 the food habits of middle-aged Danish men and women changed in the direction of a more healthy diet as recommended by health authorities. With the limitation of a possible reporting bias both the cohort and repeated cross-sectional study designs may be used for monitoring changes in food intake.