Objective: To examine the reproducibility of 24-hour dietary recall for estimating dietary vitamin intakes by middle-aged Japanese men and women.
Methods and results: The subjects were 132 men and 130 women aged 40-69 years, selected from participants in cardiovascular risk surveys conducted in 4 communities. The reproducibility of the 24-hour dietary recall was tested by comparing nutrient and food intake for two recalls conducted on the same season 1 year apart, designated as recalls 1 and 2. Differences in mean values between two recalls were tested using analysis of variance, and Spearman rank correlation coefficients for the two recalls were calculated for nutrient and food intakes. Mean values of energy and vitamins for both sexes were generally similar for the two recalls. The reproducibility of recall by men was high for vitamin B2, folate, pantothenic acid, and vitamin C and by women for vitamin B2, moderate by men for vitamins A, E, K, B1, B6 and niacin, and by women for vitamins A, E, K, B1, B6 and niacin, folate, pantothenic acid and vitamin C, and low by both men and women for vitamins D and B12. The reproducibility during 1985-1999 was generally lower than that of 1973-1984, but that for folate, pantothenic acid and vitamin C remained to be moderate in 1984-1999.
Conclusions: Although the reproducibility of 24-hour dietary recall varies among vitamins, moderate and sustained reproducibility was observed for folate, vitamin C and pantothenic acid.