Validation of a food frequency questionnaire in the Hiroshima/Nagasaki Life Span Study.

We evaluated the performance of a 22-item food frequency questionnaire (FFQ) administered in 1980-81 to 3,005 members of the Adult Health Study cohort, part of the Life Span Study. The questionnaire was compared with the records of a 24-hour dietary survey that was performed in 1984-85. From the dietary records, food and nutrient intakes were estimated. The association between the two measures of dietary intake was assessed using Mantel-Haenszel chi-square test and the Spearman's rank correlation coefficient. The frequency of food intake as measured by the FFQ was linearly associated with food intake as measured by the 24-hour diary, with the exception of dry fish. The highest correlations were observed for beverages, including coffee (0.51), milk (0.32) and black tea (0.26). Foods such as fruit (0.27), confectionery (0.23), rice (0.34) and bread (0.28) were also moderately correlated. These results show that, with the exception of dry fish, the FFQ is moderately correlated with the 24-hour diary and can be used to assess diet intake in this cohort.