Validation of simplified diet history questionnaire.

Simplified methods to estimate long term nutrient intakes would be needed for not only nutritional epidemiologic studies but also other ones. Based on data of diet history questionnaires (DHQ) which ask frequency and portion size for 169 items from 2,371 participants randomly selected from our cohort study in a rural city of Japan, we simplified the DHQ by eliminating some items using stepwise regression method. To examine the validity of the simplified DHQ (SDHQ), we obtained the SDHQs from 31 volunteers who had finished to complete one-day records once a month during the previous year, we calculated Pearson's correlation coefficient and calorie-adjusted correlation coefficient between the SDHQ and twelve one-day records for each nutrient intake value. Thirty one items were selected for our SDHQ. The mean values of most nutrient intakes from the SDHQ were more than those from twelve one-day records. The correlation coefficients between the SDHQ and twelve one-day records were more than 0.30 except for fat and monounsaturated fat. Calorie adjustment increased in the correlation coefficients for some nutrients. Our results suggest that the SDHQ is a validated and easy-to-use method for assessing long term 17 selected nutrient intakes.