A comparison of three dietary methods for estimating vitamin A intake

This study compared and evaluated vitamin A intake measured by three dietary methods (the 24-hour recall, the three-day food record, and a food frequency questionnaire) in 82 adult men enrolled in the Multiple Risk Factor Intervention Trial in Pittsburgh, Pennsylvania, during 1981. The dietary methods may be useful for group data, although differences were found: the food frequency questionnaire produced the highest mean daily estimate (7,876 +/- 569 IU) (mean +/- standard error), the 24-hour recall the intermediate daily estimate (6,944 +/- 602 IU), and the three-day food record the lowest daily estimate (5,137 +/- 470 IU). There was considerable variability between methods in individuals, suggesting that the intake of vitamin A estimated by one dietary method does not predict the intake estimated by another. At the individual level, a low significant correlation (rs = 0.28) occurred between the food frequency questionnaire and the three-day food record methods. Modest agreement in quartile ranking between these two methods indicated that 38% of the individuals fell into the same quartile, 73% into the same +/- one quartile, and 7% into opposite quartiles.