Food Diversity Is Closely Associated With Activities of Daily Living, Depression, and Quality of Life in Community‐dwelling Elderly People

To the Editor: Dietary quality and diversity are closely associated with longevity,1 and several dietary guidelines have long emphasized the value of eating a variety of foods,2 but changes in health status with aging, such as deterioration of chewing ability,3 can lead to reduced food diversity.4 To examine the association between food diversity and health status in community-dwelling elderly people, questionnaires were developed that allow an assessment of food diversity. Through these questionnaires, the health status of elderly people who scored high and low in terms of food diversity were compared. The study population consisted of 689 community-dwelling people aged 65 and older (288 men, 401 women; mean age 75.7±7.3) living in Tosa, Kochi Prefecture, Japan (39.1% of the eligible population in the town). Subjects suspected of having cognitive impairment based on criteria of Japanese Ministry of Health, Welfare and Labor and those with scored less than 23 on the Mini-Mental State Examination were excluded. Information on food diversity and geriatric functions was obtained using self-reported questionnaires in 2008. Food diversity was determined using an abridged 11-item Food Diversity Score Kyoto (FDSK-11) revised from the Japanese dietary variety score5 and National Nutritional Survey, Japan. The FDSK-11 consists of 11 main food groups (grain, meat, fish and shellfish, eggs, milk, beans and soybean products, potatoes, vegetables, seaweed, nuts and fruits); each participant rated the frequency of eating these foods over 1 week. Participants were asked whether they had eaten each of the 11 food groups for 1 day or more (a score of 1) a week or less (a score of 0). Scores were summed to provide a FDSK-11 ranging from 0 to 11, with a higher score indicating greater food diversity. Geriatric functions were assessed by measuring activities of daily living (ADLs), depression, and quantitative subjective quality of life (QOL), as well as through medical examinations. To assess basic ADLs, scores for seven items (walking, ascending and descending stairs, feeding, dressing, using the toilet, bathing, and grooming) were summed using a rating scale from 0 (completely dependent) to 3 (completely independent) to obtain a basic ADL score (0–21).6 For advanced ADLs, the Tokyo Metropolitan Institute of Gerontology Index of Competence rating scale (0–13) was used.7 This scale measures instrumental self-maintenance (0–5), intellectual activity (0–4), and social roles (0–4). Depressive symptoms were screened for using the Japanese version of the 15-item Geriatric Depression Scale.8 Quantitative QOL was assessed using a 100-mm visual analogue scale (lowest QOL on the left end of the scale, highest on the right), which includes five items: subjective sense of health, relationship with family, relationship with friends, financial satisfaction, and subjective happiness.9 Chewing ability was reported using a self-rated questionnaire on a yes or no basis.4 Body mass index was calculated using height and body weight measured during the medical examination. Statistical analysis was performed using SPSS (SPSS, Inc., Chicago, IL). P<.05 indicated statistical significance. The mean FDSK-11 score was 9.9±3.0. Scores were classified into two groups using 9/10 as the cutpoint. Table 1 shows the comparison of health status between subjects with high and low food diversity scores. Elderly participants with lower food diversity scores were significantly older (77.9 vs 75.4) than those with higher scores. Mean scores for each ADL were significantly lower in participants with lower food diversity scores than those with higher scores even after adjusting for the effect of age. Geriatric Depression Scale scores were significantly higher and subjective QOL was lower in participants with lower food diversity scores than those with higher scores. A close association was found between lower food diversity and chewing difficulty. Earlier studies reported that nutritional adequacy of a diet can be predicted by counting the number of foods groups taken.10 In this study, all food groups from National Nutritional Survey, Japan were used except for seasonings and condiments, and significant health-related differences were found between participants with high and low FDSK-11 scores. In conclusion, food diversity was closely associated with ADLs, depression, and subjective QOL in community-dwelling elderly people. This suggests that the FDSK-11 could serve as a useful indicator in screening for food diversity in elderly people living in communities. In addition to preventing malnutrition, assessing food diversity will provide an estimate of comprehensive geriatric functions. This study was partly supported by a Grant-in-Aid of JSPS Global COE Program (E-04): In Search of Sustainable Humanosphere in Asia and Africa, and a Grant-in-Aid of the Research Institute for Humanity and Nature (3–4 FR): Human Life, Aging, and Disease in High-Altitude Environments: Physio-medical, Ecological and Cultural Adaptation in the Great “Highland Civilizations.” We are grateful to the participants and staff in Tosa. Conflict of Interest: The editor in chief has reviewed the conflict of interest checklist provided by the authors and has determined that the authors have no financial or any other kind of personal conflicts with this letter. Author Contributions: Yumi Kimura, Taizo Wada, and Kozo Matsubayashi contributed to the study concept and design, analysis and interpretation of data, and preparation of the manuscript. All contributing authors aided in the survey and interpretation of data, helped with manuscript revisions, and read and approved the manuscript. Sponsor's Role: None.