Comparison of diet measures from a food-frequency questionnaire with measures from repeated 24-hour dietary recalls. The Norwegian Women and Cancer Study.
ABSTRACT To compare diet measures from a food-frequency questionnaire (FFQ) with measures from 24-hour dietary recalls (24HDRs).
The participants answered an FFQ after completing four, repeated 24HDRs during a year.
Of 500 women randomly selected from The Norwegian Women and Cancer Study (the Norwegian arm of the European Prospective Investigation into Cancer and Nutrition), 286 agreed to participate and 238 completed the study.
On the group level, the FFQ overestimated absolute intake in seven and underestimated intake in six of 21 food groups. Intakes of energy, fat, added sugar and alcohol were lower in the FFQ than in the 24HDRs, whereas intake of fibre was higher. Spearman's rank correlation coefficient ranged from 0.13 (desserts) to 0.82 (coffee) for foods, and from 0.25 (beta-carotene) to 0.67 (alcohol) for nutrients. Three per cent of the observations on nutrient intake fell in the opposite quintile when classified according to the FFQ as compared with the 24HDR. The median calibration coefficient, calculated by regression of the 24HDR data on the FFQ data, was 0.57 for foods and 0.38 for nutrients.
The FFQ's ability to rank subjects was good for foods eaten frequently and fairly good for macronutrients in terms of energy percentages. Weaker ranking abilities were seen for foods eaten infrequently and for some micronutrients. The results underline the necessity of performing measurement error corrections.
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ABSTRACT: To examine the relation between consumption of fish and fish products registered by a comprehensive food frequency questionnaire and the composition of fatty acids in serum phospholipids. Cross-section study. Cardiovascular screening centre in Trondheim, Mid-Norway. Of 256 eligible women 242 agreed to participate in the present study. Altogether 234 middle-aged women (91.4%) completed the questionnaire and gave a valid blood sample. Total frequency consumption of fish for dinner showed only weak association with serum phospholipid fatty acid composition. In separate analyses of lean and fatty fish, consumption of fatty fish was negatively associated with n-6 and positively associated with n-3 fatty acids in serum phospholipids, while no significant associations were found for lean fish consumption. Cod liver oil consumption was strongly related to the phospholipid fatty acid composition. The associations improved moderately when adding portion size information. Spearman's correlation coefficient between dietary intake of eicosapentaenoic acid (EPA) and serum phospholipid EPA was 0.58, and Spearman's correlation coefficient between intake of docosahexaenoic acid (DHA) and serum phospholipid DHA was 0.53. This study suggests that in populations with a high consumption of fish and cod liver oil, habitual intake can be reflected in serum phospholipids. However, as the fat content of fish is highly variable, separate registration of lean and fatty fish consumption is needed.European Journal of Clinical Nutrition 12/1997; 51(11):736-42. · 2.76 Impact Factor
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ABSTRACT: A self-administered food frequency questionnaire was developed for the Dutch cohort of the European Prospective Investigation into Cancer and Nutrition (EPIC). Habitual consumption of 178 food items can be calculated from the questionnaire data. Reproducibility and relative validity for food group intake were investigated in a population of 121 Dutch men and Women. The questionnaire was administered three times at 6-month intervals in order to determine the reproducibility. To assess the relative validity 12 monthly 24-hour recalls served as the reference method. Spearman rank order correlation coefficients between estimates of food group intake assessed by repeated questionnaires ranged from 0.45 to 0.92. For men, Spearman correlation coefficients between estimates of food group intake based on the questionnaire and those based on 24-hour recalls ranged from 0.21 for cooked vegetables to 0.78 for sugar and sweet products, with a range of 0.61. For women the median was 0.53, with a minimum of 0.31 for vegetables and a maximum of 0.87 for alcoholic beverages. The photographs in the questionnaire for the estimation of portion sizes contributed little to the relative validity of the ranking of subjects. However, on the group level most median food group estimates based on photographic portion sizes were closer to the median intakes as assessed by 24-hour recalls than those based on standard portion sizes. The questionnaire seems adequate for ranking Dutch EPIC subjects according to intake of most food groups, although the relative validity for some food groups, such as vegetables and fish, remains of concern.International Journal of Epidemiology 02/1997; 26 Suppl 1:S37-48. · 6.98 Impact Factor
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ABSTRACT: A pilot questionnaire was developed for the EPIC centres of northern Italy, and validated in the feasibility part of the cohort project. The questionnaire was self-administered and of the food frequency type with portion size estimated by means of pictures. It was structured by courses within a meal characteristic of Italian dietary habits. Dietary intake estimated by the questionnaire was compared to the corresponding estimates obtained from 8-14 24-hour recall interviews administered over a 1-year period. The reference method was validated by means of urinary nitrogen in 4-6 repeated 24-hour urine collections. One hundred and ninety-seven volunteers (47 men and 150 women) were enrolled and completed the study lasting 1 year. They filled out two questionnaires at the beginning and at the end of the study, and had a 24-hour recall interview once a month. Twenty-four-hour urine samples were collected at regular intervals. Usual intake of energy, the major nutrients and some vitamins were estimated for the questionnaires and the reference method by means of food composition tables compiled for this study. The agreement between the questionnaire and the 24-hour recalls was only good for alcohol consumption: Pearson's correlation was 0.73 and 0.77 in men and women respectively. Otherwise the relative validity of the questionnaire ranged between 0.28 for fat to 0.52 for carbohydrates in men and 0.25 and 0.50 in women for the same nutrients. The validity of the two interview methods in estimating protein intake, compared to mean urinary nitrogen was 0.24 (M) and 0.18 (W) for the questionnaire and 0.63 (M) and 0.48 (W) for 24-hour recalls. The main causes of low performance of the questionnaire were identified to be the estimated intake of dressing and cooking fats, vegetables and meat. Remedies were devised and introduced in the final version of the questionnaire currently in use in the EPIC project.International Journal of Epidemiology 02/1997; 26 Suppl 1:S152-60. · 6.98 Impact Factor