Foods to be included in a Danish self-administered semiquantitative food frequency questionnaire were identified from food tables developed, together with data collected, for the survey 'Dietary habits in Denmark, 1985'. The questionnaire was to be used in a prospective study on diet, cancer and health, and the aim was to rank individuals with regard to intake of 19 different nutrients considered of prime importance in human carcinogenesis. The questionnaire for the dietary survey included 247 foods and recipes. From stepwise multiple regression analyses with the intake of each of the 19 nutrients as the dependent variable and the intake of the 247 foods and recipes as independent variables, the foods in the models explaining 90% of the between-person variability were considered for the final questionnaire. All relevant analyses were performed for the study group as a whole, for men and women separately, and in each gender for subgroups of energy intake. Taken together, the models explaining 90% of the between-person variability identified a total of 74 foods or recipes, which were important predictors of the intake of one or more of the nutrients considered. A few foods were excluded and a few foods were added to the final questionnaire based on common biological background information, and on information on foods providing important amounts of given nutrients, but which failed to contribute to regression analyses. The 92 foods and recipes, which were included in the final questionnaire provided altogether 81% of the average total supply of the nutrients.(ABSTRACT TRUNCATED AT 250 WORDS)
OBJECTIVE: Smoking serves different functions for men and women. Thus, we wanted to investigate the association between smoking behaviour and intakes of selected healthy foods in men and women with special focus on differences and similarities between the two genders. DESIGN: In 1993-1997, a random sample of 80 996 men and 79 729 women aged 50-64 y was invited to participate in the study 'Diet, Cancer and Health'. In all, 27 179 men and 29 876 women attended a health examination and completed a 192-item food-frequency questionnaire (FFQ). The association between smoking status and low, median and high intakes of selected foods was examined among 25 821 men and 28 596 women. SETTING: The greater Copenhagen and Aarhus area, Denmark. RESULTS: For both men and women, smoking status group was associated with diet, such that increasing level of smoking status ranging from never smokers over ex-smokers to currently heavy smokers was associated with a lower intake of the healthy foods: fresh fruit, cooked vegetables, raw vegetables/salad, and olive oil. For wine, increasing level of smoking status category was associated with a higher fraction of abstainers and heavy drinkers. The difference between the extreme smoking status categories was larger than the difference between men and women within smoking status categories such that never smoking men in general had a higher intake of healthy foods than heavy smoking women. Correction for age, educational level, and body mass index (BMI) did not affect the results. CONCLUSION: In this middle-aged population, intake of healthy foods were associated with smoking behaviour with a dose-response type of relationship. The overall pattern was similar for men and women.
In 1989, a self-administered food frequency questionnaire, including 92 food items and 40 portion-size photographs, was validated against two times seven days of weighed diet records. A total of 144 subjects, aged 40-64 years, from the general population in Copenhagen were included. Correlations between mean calorie-adjusted intakes from the two-week diet records and the food-frequency questionnaire ranged from 0.27 for vitamin A to 0.71 for calcium. In general, higher correlation coefficients were observed for men than for women. On average, about 70% of subjects were classified in the same (+/- 1) quintile in the food frequency questionnaire and the diet records. Of those subjects belonging to the lowest quintile, estimated from the diet records, 42% fell in the same quintile and 68% into the lowest two quintiles in the food frequency questionnaire. Findings were similar for the upper tail of the distribution. Gross misclassification, observed in the highest and lowest quintile, was found for 4% and 7% of the subjects, respectively. It is concluded that this food frequency questionnaire is a useful instrument for categorizing individuals according to their intake of nutrients and energy.