Reproducibility and Validity of Dietary Assessment Instruments

Abstract

A self-administered food use questionnaire which included 276 food items and mixed dishes and a portion size picture booklet with 122 photographs was developed for a large lung cancer intervention trial among approximately 27,000 Finnish men aged 50-69 years. The reproducibility and validity of this questionnaire were studied from March to October 1984. In the reproducibility study, 121 men aged 55-69 years completed the questionnaire three times, at three-month intervals. The intraclass correlations varied from 0.56 for vitamin A to 0.88 for alcohol, with most falling between 0.60 and 0.70. In the validity study, 190 men of similar age kept food consumption records for 12 two-day periods, distributed evenly over a period of six months, and filled in the questionnaire both before and after this period. Correlations between nutrient intake values from the food records and the food use questionnaires ranged from 0.40 for selenium to 0.80 for alcohol. Among subjects who belonged to the lowest quintile on the basis of the food record measurement, an average of 51 per cent fell into the same quintile and 76 per cent fell into the lowest two quintiles when they were categorized on the basis of the food use questionnaire. Findings were similar for the upper tail of the distribution. These data indicate that the self-administered food use questionnaire is useful for measuring individual or group intakes for a variety of nutrients.

Reproducibility of food and nutrient intake estimates using a semi-quantitative FFQ in Australian adults

“…Our results are comparable to those from studies of similar FFQ used in Western adult populations, where the ICC between two administrations of the FFQ ranged from 0?50 to 0?70 (6) or from 0?40 to 0?95 (21,22) . The ICC we obtained were closer to those from the Nurses' Health Study (10) and the Health Professionals Follow-up Study (23) than the Helsinki Diet Methodology Study (24) or the Stroke in the Elderly Study (25) , which reported somewhat better repeatability perhaps due to the presence of older adults (55 years and older; see Table 4). Reproducibility of nutrient intake among the elderly has been reported to be particularly high (6,25) as older people may be more established in their dietary habits than younger groups (25) .…”

“…Our results are comparable to those from studies of similar FFQ used in Western adult populations, where the ICC between two administrations of the FFQ ranged from 0?50 to 0?70 (6) or from 0?40 to 0?95 (21,22) . The ICC we obtained were closer to those from the Nurses' Health Study (10) and the Health Professionals Follow-up Study (23) than the Helsinki Diet Methodology Study (24) or the Stroke in the Elderly Study (25) , which reported somewhat …”

“…provided statistical expertise, interpretation of data and edited manuscript; P.M.W., principal investigator, conceptualized the study, performed field work planning and data collection, and edited the manuscript. (10) Helsinki Diet Methodology Study (24) Health Professionals' Follow-up Study (23) Stroke in the Elderly Study (25) …”

Validation and reproducibility of food frequency questionnaire for Korean genome epidemiologic study

“…The foodfrequency questionnaire (FFQ) is a tool for the estimation of food and nutrient consumption and has been widely used in investigating the association between diet and chronic diseases in large population-based studies (Willett et al, 1985;Pietinen et al, 1988). This method has an advantage in that a long-term, usual dietary intake of an individual can be easily obtained by making a single measurement.…”

Reproducibility of a food frequency questionnaire used in the New York University Women’s Health Study: Effect of self-selection by study subjects

“…As some measurement error will, however, always occur, additional substudies may be conducted to estimate the magnitude of statistical power loss or bias in estimates of diet-disease associations, incurred by the inaccuracy of dietary questionnaire measurements. These substudies can take the form either of a reproducibility study, based on successive administrations of the questionnaire, usually over a six-to twelve-month interval (Hankin et al, 1983;Wu et al, 1988;Jain et al, 1989;Ja Èrvinen et al, 1993) or à validity' study, using a comparison with records of actual food consumption during a number of days as well (Willett et al, 1985;Pietinen et al, 1988aPietinen et al, , 1988bMunger et al, 1992;Rimm et al, 1992;Callmer et al, 1993). In both types of substudy, with or without additional reference measurements, there is the potential problem that participation rates may be lower than 100% (in some studies, participation rates as low as 20% have been reported (Munger et al, 1992)), and that there may be self-selection of volunteers whose capacity or motivation to respond accurately to the dietary questionnaires is above average.…”