[Relationship between eating alone and dietary variety among urban older Japanese adults]

Objectives　This study aimed to investigate the practice of eating alone, including its frequency, among urban older Japanese adults and to clarify its association with dietary variety.Methods　In June 2016, self-reported questionnaires were mailed to 15,500 men and women aged 65 years or older living in Ota City, Tokyo without nursing care certification. Of these, 11,925 questionnaires were returned (a 76.9% response rate), and responses from 8,812 subjects were analyzed (a 56.9% valid response rate). The frequency of eating alone, defined as the number of days per week eating alone for each meal, was reported as zero, one to three, four to six, or seven days. A Dietary Variety Score (DVS) was obtained based upon consumption frequencies per week of 10 food groups. Total points were calculated, and three or fewer points indicated low dietary variety. The association between eating alone and low dietary variety was analyzed by binomial logistic regression, with adjustments for potential confounding variables including age, body mass index (BMI), location, educational history, equivalent income, employment, living alone, medical history, and smoking and drinking habits.Results　The results indicated that 47.1% of men and 48.5% of women ate alone at least one day per week, and 14.9% of men and 16.9% of women ate alone every day. For men, after adjusting for potential confounders (ORs=1.51-2.00), the odds ratios (ORs) of low DVSs were significantly higher among those who ate alone one to three days, four to six days, or seven days per week compared to those who ate with others. For women, adjusted ORs were not significant among those who ate alone every day (OR=1.15, 95% CI=0.92-1.43). Men and women who ate alone had significantly lower ORs of eating green or yellow vegetables, fruits, and fats/oils almost every day compared to those who ate with others.Conclusion　Among urban Japanese older adults, about 50% of subjects reported eating alone. Eating alone was associated with lower dietary variety scores regardless of age, income, and family status. Therefore, the present findings might be useful for developing strategies for addressing undernutrition among urban older adults eating alone.