Relative Validity of Brief-type Self-administered Diet History Questionnaire Among Very Old Japanese Aged 80 Years or Older

Objective: Dietary questionnaires for assessing dietary intakes among populations of individuals aged 80 years or older (the very old) are very limited. We examined the relative validity of forty-three nutrients and twenty-seven food groups estimated by a brief-type self-administered diet history questionnaire (BDHQ) targeting very old Japanese, using semi-weighed dietary records (DR) as a reference.

Design: Between June and August 2012 and between June 2015 and February 2016, a three-day non-consecutive DR (at two-week intervals) and a BDHQ were completed.

Setting: Tokyo, the capital prefecture of Japan.

Subjects: Eighty very old Japanese (thirty-six men and forty-four women) aged 82-94 years.

Results: The median intakes of 40-70 % of the crude and energy-adjusted nutrients estimated by the BDHQ were significantly different from those estimated by the DR. The median Spearman's correlation coefficient of nutrient intakes between the BDHQ and the DR was 0·39-0·46. About half (48-56 %) of the food groups were significantly different in terms of the median intakes estimated by the BDHQ and the DR in crude and energy-adjusted values. The median Spearman's correlation coefficient between the BDHQ and the DR was 0·45-0·48.

Conclusions: Acceptable Spearman's correlations (≥0·3) were obtained for many dietary intakes among the very old Japanese population. The BDHQ is a good candidate for epidemiological studies among very old Japanese, although, for some nutrients and food groups, the difficulty of estimating accurate median intakes is one of the limitations for the tool. Further efforts to enhance the validity of the BDHQ for very old populations are needed.