Dietary diversity and 14-year decline in higher-level functional capacity among middle-aged and elderly Japanese

Abstract

ObjectivesThis study aimed to clarify the effects of dietary diversity on a decline in higher-level functional capacity among middle-aged and elderly subjects in Japan. MethodsData were derived from the National Institute for Longevity Sciences - Longitudinal Study of Aging. Subjects comprised 1317 men and women aged 40 to 79 at baseline (1997–2000) who participated in a follow-up postal survey (2013). Higher-level functional capacity was measured using the Tokyo Metropolitan Institute of Gerontology index of competence (total score and 3 subscales). Dietary intake was assessed using a 3-d dietary record, and dietary diversity was determined using the Quantitative Index for Dietary Diversity (QUANTIDD). The odds ratios and 95% confidence intervals (CI) for a decline in higher-level functional capacity in the follow-up study according to quartiles of QUANTIDD at baseline were estimated, controlling for age, sex, higher-level functional capacity scores at baseline, body mass index, alcohol consumption, physical activity, depressive score, household income, education, smoking, and disease history. ResultsA total of 214 (16%), 145 (11%), 70 (5%), and 136 (10%) subjects showed a decline in total score for higher-level functional capacity (≥2), instrumental self-maintenance (≥1), intellectual activity (≥2), and social role (≥2), respectively. Multivariate-adjusted odds ratios (95% confidence intervals) for the score for intellectual activity decline according to the lowest through highest quartiles of QUANTIDD were 1.00 (reference), 0.47 (0.23–0.95), 0.44 (0.22–0.90), and 0.41 (0.20–0.83), respectively (P for trend = 0.06). ConclusionsDaily intake of various foods may protect against a decline in intellectual activity among middle-aged and elderly community dwellers in Japan.