Abstract

This study examined within- and between-person variation in nutrient intakes in order to estimate the degree of precision in dietary assessment among 37 males and 46 females whose mean age was 70.4 years old. To collect dietary data, each subject was interviewed 5 or 6 times using a 24-hour recall method during a 3 month period. Within-person variation ranged from 23.5% to 101.2%. Lower values of within-person variation were observed in energy, carbohydrated, protein and phosphorous while higher value was observed in vitamin A. Between person variations of nutrient intakes ranged 12.6-23.5% in most nutrients. With 1 day dietary data, observed nutrient intakes were estimated to within 6-25% of the group's usual9true) intakes and 52-198% of the individuals' usual intakes. The values of these maximum percentage deviations became smaller when the number of dietary recalls increased. The results of this study suggest that the Korean elderly subjects appear to have a slightly less diverse diet compared to young Korean women. Within persons, intakes of nutrients largely from animal sources were more variable for the Korean elderly than for their counterparts in Western countries. This study also implies that commonly used 1 day dietary study may be appropriate for assessing group means of nutrient intakes, but clearly not appropriate for assessing individual's nutrient intakes.

• Keywords: within-and between person variation; nutrients; Korean elderly