Adipose tissue fatty acids, it has been proposed, reflect dietary intake. Using data from a validation study preceding a prospective study on diet, cancer, and health in Denmark, we were able to compare fatty acid profiles in adipose tissue biopsies from 86 individuals (23 men and 63 women) aged 40-64 y and dietary intake of fatty acids (as percentage of total fat) assessed by two 7-d weighed-diet records or by a semi-quantitative food frequency questionnaire. Correlation coefficients (Pearson r) between fatty acid concentrations in adipose tissue biopsies (as percentage of total peak area) and dietary intake of fatty acid (percentage of total fat), determined from the diet records for men and women, respectively, were as follows: polyunsaturated fatty acids r = 0.74 and r = 0.46; n - 3 fatty acids of marine origin: eicosapentaenoic acid r = 0.15 and r = 0.61, and docosahexaenoic acid r = 0.47 and r = 0.57. Correlation coefficients obtained by using the food frequency questionnaire were slightly lower for most fatty acids.
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)
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.