The Journal of Nutrition, Health & Aging© Volume 16, Number 8, 2012

EATING ALONE AMONG COMMUNITY-DWELLING JAPANESE ELDERLY: ASSOCIATION WITH DEPRESSION AND FOOD DIVERSITY

Y. Kimura1, T. Wada2, K. OKumiYa3, Y. ishimOTO1, E. FuKuTOmi1, Y. Kasahara1, W. ChEN1, r. saKamOTO3, m. FujisaWa4, K. OTsuKa5, K. maTsubaYashi1,2

1. department of Field medicine, school of Public health, Kyoto university, Kyoto, japan; 2. Center for southeast asian studies, Kyoto university, Kyoto, japan; 3. research institute for humanity and Nature, Kyoto, japan; 4. Wild animal research Center, Kyoto university, japan; 5. medical Center East, Tokyo Women’s medical university, Tokyo, japan. Corresponding author: Yumi Kimura, department of Field medicine, school of Public health, Kyoto university, 46 shimoadachi-cho, Yoshida, sakyo-ku, 606-8501 Kyoto, japan. TEL: +81-75-753-7368, FaX: +81-75-753-7168, E-mail: [email protected]. alternate Corresponding author: Kozo mastubayashi, E-mail: [email protected]

Abstract: Eating alone is an emerging social concern these days along with the background of serious aging population growth and increasing number of single-dwellers in japan. however, little study is focused eating alone and its relation to the health status of community-dwelling elderly. Objectives: To clarify the relations between eating alone and geriatric functions such as depression, quantitative subjective quality of life (QOL), activities of daily living (adL) and dietary status of community-dwelling japanese elderly. Design: a crosssectional study. Settings: Tosa town, one of the "super-aged" towns in japan. Participants: The study population consisted of 856 communitydwelling elderly aged ≥65 living in Tosa town. Measurements: Eating alone and living arrangement was defined by the questionnaire. Geriatric functions were assessed by measuring activities of daily living (adL), depressive symptom using 15-item Geriatric depression scale (Gds-15), and quality of life (QOL). Food diversity was investigated as a measure of dietary quality using 11-item Food diversity score Kyoto (FdsK-11). body mass index (bmi) was calculated using height and body weight during a medical assessment. Results: The proportion of the elderly who usually eat alone was 33.2% in this study population. Even among 697 elderly subjects who live with others, 136 persons (19.5%) ate alone. The participants who ate alone were significantly depressed according to the assessment using Gds-15 score (5.7±4.3 vs. 4.4±3.8, P<0.001). Those who ate alone have lower scores of QOL items than those who ate with others (subjective sense of health: 52.5±21.9 vs. 55.7±20.2 P=0.035, relationship with family: 74.1±23.5 vs. 78.9±18.6 P<0.001, subjective happiness: 58.5±22.7 vs. 62.2±21.1 P=0.019). a significant close association was found between eating alone and lower food diversity (FdsK-11 score 9.9±1.3 vs. 10.2±1.3, P=0.002). bmi was lower in the elderly subjects who ate alone than those with others. by the multivariate analysis, depression was independently associated with eating alone in the logistic regression model adjusted for age, sex, bmi and food diversity as confounding factors (Or: 1.42, Ci: 1.00-2.11, P=0.043). Food diversity was also significantly associated even after the adjustment of these confounding factors. Conclusion: Eating alone is an important issue related to depression and QOL as well as dietary status of community-dwellingl elderly in japan. This study shows the simple and inexpensive way "eating together" may contribute to improve depressive mood of elderly persons, with a strong message that supports of family, friends and neighbors are very important. Key words: Eating alone, community-dwelling elderly, quality of life, depression, food diversity.

Introduction

japan has the world’s highest aging rate due to increased longevity and a drastic decline in birth rates (1). according to the latest japanese National Census at the end of 2010, there are nearly 29 million people aged ≥65, accounting for 22.7% of the total population. if this demographic trend continues, the percentage of elderly people will rise to 40.5% in 2055, which means that each elderly person will be supported by 1.3 people of productive-age (15-64 years old). The percentage of “olderelderly” aged ≥75 is estimated to reach 26.5% by 2055 (2). The number of elderly people living alone has increased along with the increase in the aging population. The ministry of health, Labour and Welfare reported that the percentage of elderly living alone increased from 4.3% for males and 11.2% for females in 1980, to 9.7% for males and 19.0% for females in 2005 (3). at present, it seems impossible to intervene and directly improve the issue itself because of the structural Received August 13, 2011 Accepted for publication October 17, 2011

character. Thus, addressing health problems among the elderly population under this situation is a priority in japan. health of the elderly is affected by various lifestyle factors and diet is one of them. attention should be paid to eating behavior such as; when, where and with whom they eat as well as nutritional assessment. Eating alone is an emerging social concern with the background of an increasing elderly population and number of living alone. Eating together is a universal custom of humans all over the world. People used to dine together with family, friends or people in the same community as a regular basis for long years. Particularly in japan, dining together holds a culturally important meaning that transcends merely having a meal together (4). Eating alone is called “Koshoku” in japanese, or literally means “solitary eating", which includes a meaning of loneliness. The change from the custom of eating together to eating alone might associate with depressive mood and other geriatric health status of the elderly.

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Previous studies have found that eating behaviors affect health. For example, having somebody present during meals has been reported to increase caloric intake of the elderly subjects, while living together didn't contribute to increase the caloric intake (5). although eating situation is known to be affected by various social factors such as the living arrangements, economic status and education (6), little study is focused on the health status of community-dwelling elderly who eat alone. Eating alone is more studied among children and the latest review article suggested that eating alone among children leads to obesity (7). The aim of this study is to clarify the relations between eating alone and health status among community-dwelling elderly in japan, especially focused on geriatric functions such as depression, quantitative subjective quality of life (QOL), activities of daily living (adL), and dietary status. Study design a Cross-sectional study.

Methods

Study population We conducted the geriatric health survey in Tosa town, Kochi Prefecture, japan in 2008. as a part of the survey, we prepared questionnaire to ask their health-related statuses, which was used for this study. With support of the health staffs in Tosa town, we posted the questionnaire to all the 1,679 community-dwelling elderly aged ≥65 except for 150 elderly individuals living in hospitals or nursing homes in 2008. We collected 1,060 questionnaires (response rate, 69.3%) and 856 subjects completed the applicable questionnaire for this study. The subjects consists of 347 men and 509 women and mean age is 76.6 years; standard deviation, 7.8. Tosa town is a rural farming town in a mountainous area and is also known as a “super-aged” town, with individuals ≥65 years accounting for 40.0% of the total population (4,576) in 2008. The demographic structure of Tosa is similar to that of the predicted japanese population in 2055.

Eating situation and living arrangements Participants were asked to respond “yes” or “no” to the question, “do you usually eat alone?” to identify the eating situation. We also asked about living arrangements to determine whether each participant lived alone or with someone.

Geriatric functions Geriatric functions were assessed by measuring depression, and quantitative subjective quality of life (QOL) and activities of daily living (adL). We screened for depressive symptoms using the japanese version of the 15-item Geriatric depression scale (Gds-15) (8, 9). Quantitative QOL was assessed using a 100-mm visual analogue scale (lowest QOL on the left, highest on the right) that includes five items: subjective sense of health, relationship with family, relationship with friends, financial satisfaction, and

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subjective happiness (10). To assess basic adL, all participants were scored from zero (completely dependent) to three (completely independent) on their ability to perform seven tasks: walk, ascend and descend stairs, feed themselves, dress, use the toilet, bathe, and groom. scores of these individual components were summed into a basic adL score ranging from zero to 21, with low scores indicating disability (11, 12). For advanced adL, we used the Tokyo metropolitan institute of Gerontology index of Competence (TmiG-iC) (13), which is a rated scale (0-13) that includes instrumental self-maintenance (0-5), intellectual activity (0-4), and social role (0-4).

Dietary status Food diversity was assessed as a measure of dietary quality using the 11-item Food diversity score Kyoto (FdsK-11) (14). FdsK-11 includes 11 main food groups (grain, meat, fish and shellfish, eggs, milk, beans and soybean products, potatoes, vegetables, seaweed, nuts, and fruits) and each participant rated the frequency of eating these foods during a week: once or more a week (a score of 1) or less (a score of 0). scores were summed to provide a FdsK-11 score ranging from 0-11, with a higher score indicating higher food diversity. We also assessed oral function as an indicator for nutritional status. Participants were asked to respond “yes” or “no” to the question, “in the past 6 months, have you had difficulty chewing when you eat hard foods?” to identify deterioration in chewing ability (15). body mass index (bmi) was calculated using height and body weight during a medical assessment. Statistical analysis First, comparison of each scores and proportions between eating alone and with others were analyzed by student’s t-test for continuous variables and the chi-square test for categorical variables. Effect of age was adjusted by aNCOVa for continuous variables. Categorical variables such as sex, proportion of depression and chewing difficulty were adjusted by logistic regression model. second, multivariate analysis was performed by logistic regression model. Eating alone/with others was the dependent variable. The primary exposure was depression and other possible confounding factors were adjusted in this analysis. P<0.05 indicated statistical significance. statistical analysis was performed using sPss version 19.0 for Windows (sPss inc., Chicago, iL). Ethical Clearance This study was approved by The Ethical Committee of Faculty of medicine, Kyoto university in Kyoto, japan (E514). Results

The proportion of elderly who usually eat alone was 33.2% in this study population. The composition of living and eating arrangements was: 148 participants lived alone and ate alone, 136 lived with others but ate alone, 561 lived and ate with

The Journal of Nutrition, Health & Aging© Volume 16, Number 8, 2012

EATING ALONE AMONG COMMUNITY-DWELLING JAPANESE ELDERLY

others, and 11 lived alone but ate with others (Table 1). This means, even among 697 elderly subjects who live with others, 136 persons (19.5%) ate alone. Table 1 Number of the elderly subjects who ate alone and with others within the divisions of living arrangement

Living alone Living with Others

Eating Alone 148 (93.1% ) 136 (19.5%)

Eating with Others Total Number 11 (6.9%) 561 (80.5%)

159 (100%) 697 (100%)

(%) shows proportion of eating alone/with others among the total population of living alone/with others

Table 2 compares geriatric functions and dietary status between elderly who ate alone and those who ate with others. Those who ate alone had a higher mean age and included more women. Elderly subjects who ate alone had significantly higher Gds-15 scores and proportion of depression (Gds-15≥10) than those who eat with others. Table 2 Comparison of geriatric functions and dietary status between elderly who eat alone and those who eat with others Eat Alone

age, mean ± sd Gender (male/female) Geriatric functions depression Gds-15 score (range 0-15) Gds-15 score ≥10 (%) QOL, mean ± sd (range 0-100) subjective sense of health relationship with family relationship with friends Financial satisfaction subjective happiness adL, mean ± sd basic adL score (range 0-21) TmiG-iC score (range 0-13) self-maintenance (range 0-5) intellectual activity (range 0-4) social role (range 0-4) Dietary Status FdsK-11, mean ± sd (range 0-11) body mass index, mean ± sd Chewing difficulty (%)

(N=284)

77.6±7.5 72/212 5.7±4.3 22.9

Eat with P-Value [1] P-Value [2] Others (N=572) 75.7±7.5 275/297

－ －

4.4±3.8 12.2

<0.001 <0.001

0.001 0.001

19.7±3.0 10.7±3.1 4.3±1.3 3.1±1.1 3.2±1.1

0,56 0.19 0.82 0.15 0.33

0.30 0.59 0.81 0.14 0.55

52.5±21.9 74.1±23.5 74.7±23.1 51.1±24.7 58.5±22.7

55.7±20.2 78.9±18.6 75.7±19.5 50.0±22.9 62.2±21.1

9.9±1.3 22.9±3.0 22.8

10.2±1.3 23.5±3.1 20.0

19.6±2.3 10.4±2.9 4.4±1.4 2.9±1.2 3.1±1.1

0.001 0.001

0.035 <0.001 0.22 0.61 0.019

0.002 0.045 0.14

0.042 0.007 0.33 0.77 0.038

0.031 0.12 0.32

sd: standard deviation; Gds-15: 15-item Geriatric depression scale; QOL: Quality of Life; TmiG-iC: Tokyo metropolitan institute of Gerontology index of Competence; FdsK-11: 11-item Food diversity score Kyoto; differences were analyzed by the student's t-test for continuous variables and the chi-square test for categorical variables. Pvalues [1]: adjusted for age in the items of geriatric functions and dietary status by aNCOVa. P-values [2]: adjusted for age and sex in the items of geriatric functions and dietary status by logistic regression analysis.

Elderly who ate alone had significantly lower QOL scores in the items of subjective sense of health, relationship with family, and subjective happiness than those who ate with others. Eating alone was also significantly associated with lower food diversity. bmi was lower in the participants who ate alone, although it lost its significance after the adjustment for sex. For further understanding, we conducted statistical

analysis separately by sex and confirmed that lower bmi was significantly associated with eating alone in men. multivariate analysis was performed to confirm the association between eating alone and depression after adjustment for possible confounding factors which had significant associations with eating alone in the previous analysis (Table 3). model 1 is the basic model to adjust for age and sex. bmi was added in the model 2, and food diversity was added in the model 3. We did not include QOL as independent variables in these models as depression and QOL have similar characteristics. This revealed that eating alone was associated with depression independently from the effect of age, sex, bmi and food diversity. association with eating alone and food diversity was also significant in the model 3. Discussion

We revealed that as many as 33.2% of the communitydwelling elderly persons ate alone. although “eating alone” is seemingly similar to “living alone” or results from living alone, we found that nearly 20% of the elderly who lived with their families still ate alone. as far as we know, this is the first study to clarify the actual population of eating alone, and its relation to the health status in the community-dwelling elderly. Eating alone was related to depression of the elderly subjects. Eating alone might affect depressive mood as it makes persons feel loneliness by lack of communication during meals. “To eat alone is the saddest thing in the world,” said a 91-yearold person during a qualitative interview conducted in spain (16), which concluded that elderly people feel loneliness through food practices and are more depressed when they eat alone. some quantitative studies also explain the effect of dietary status on mood, such as decreases in appetite being related to depression and emotional well-being (17). Communication with family is significantly associated with good appetite (18), which also relates to depression. The association between lower QOL, especially with regard to relationship with family, and eating alone might be supported by these previous studies. since more women than men ate alone in this study, we considered the effect of gender on depression, which has been shown to be more prevalent in women (9). a significant relationship was still observed between eating alone and depression after adjusting for gender, and the other possible confounding factors. Eating alone was related to less varied diet. Food diversity is one of the important dietary factors to reflect the dietary quality, and it’s known to be associated with health status in elderly individuals (14, 19) and even mortality (20). it might be difficult for the elderly to motivate themselves to prepare various types of foods and to enhance appetite at the solitary table. Previous studies have suggested that eating alone acts as a barrier for healthy food choices (21). depressive symptoms are reported to be associated with food insufficiency (22), which also supports our finding of eating less varied foods among the elderly who eat alone. The association between eating alone and lower bmi can be

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Table 3 association between eating alone and depression adjusted for possible confounding factors by multivariate logistic regression analysis Independent Variables

age sex (female) depression (Gds-15 ≥10) bmi Food diversity (FdsK-11 score)

OR

1.03 2.84 1.61 -

Model 1 95% CI

1.00-1.05 1.98-4.86 1.14-2.27 -

P-Value

OR

0.028 <0.001 0.006 -

1.03 3.05 1.59 0.98 -

Model 2 95% CI

1.00-1.05 2.04-4.57 1.08-2.34 0.92-1.04 -

P-Value 0.049 <0.001 0.019 0.402 -

OR

1.03 3.21 1.42 0.97 0.76

Model 3 95% CI

1.00-1.05 2.13-4.84 1.00-2.11 0.91-1.03 0.64-0.97

P-Value 0.051 <0.001 0.043 0.279 0.002

Or: Odds ratio; Ci: Confidence interval; －: Not used in the model; model 1: adjusted for age and sex ; model 2: adjusted for age, sex and bmi; model 3: adjusted for age, sex, bmi and food diversity

also explained by the food insufficiency. This result is in direct contrast to the previous children’s study suggesting that eating alone among children leads to obesity (7). Children are known to eat unhealthy food, such as fatty snacks or fast food, when they eat alone. Thus, our study underscores the fundamental differences between children and the elderly in this context. Eating alone might lead to malnutrition in the elderly, as evidenced by a lower bmi. There were no significant differences in adL scores between participants who ate alone and those who ate with others, indicating that these two groups are similar in adL independency. associations between eating alone and depression, QOL and food diversity are therefore pronounced despite similar levels of adL status. as this study is a cross-sectional study, we cannot mention the cause and effect clearly. however, we found the significant close association between eating alone and depression, which tells that eating alone should be paid attention in relation to depression. Living alone is difficult to avoid in many cases with increasing aging population, but eating alone can be intervene by the support of family, friends and neighbors especially from the fact that about 20% of the elderly subjects ate alone while they lived with their family. Further longitudinal study is necessary to know the effect and look for the possibility of intervention. additionally, this study was limited by its study population, which was approximately 50% of the eligible population. an important task in the future will be to include non-participants in the study because those who did not participate may be more isolated from social networks than those who did, and the proportion of eating alone may thus be higher.

important.

Eating alone is an important issue related not only to dietary status, but also to depression and quality of life of communityliving elderly in japan. This simple and obvious finding suggests that eating alone should be recognized as a notable health-related factor. moreover, this study shows the simple and inexpensive way “eating together” may contribute to improve depressive mood of elderly persons, with a strong message that supports of family, friends and neighbors are very

18.

Conclusion

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Acknowledgements: This study was supported in part by a Grant-in-aid to the jsPs Global COE Program (E-04): in search of sustainable humanosphere in asia and africa, and a Grant-in-aid to 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 also grateful to the participants and staffs in Tosa. 1.

2. 3. 4. 5.

6. 7.

8. 9.

10. 11. 12. 13. 14.

15. 16. 17.

19. 20. 21.

22.

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