Changes in household composition due to economic growth and alterations in social structure of Korea have resulted in a steady decline in the number of household members.[1] From 1990 to 2005, the 4-person household was the major household type; however, in 2010, the rate of 2-person households increased, and from 2015, the rate of single-person households has increased significantly.[2]

The Statistics of Korea define single-person households as individuals living alone in general households i.e., households where a single person is sleeping, cooking, and living independently.[3] These single-person households are affected by economic factors such as unstable employment, low income level, and expansion of employment for women as well as by social factors such as high education level, increasing age at the time of first marriage, increase in divorce rate, increase in individualism, changes in marriage, and rapid aging.[45] It is rapidly increasing due to various factors. In particular, the number of elderly people aged 65 years or older who live alone is rapidly increasing due to population aging.[6]

Increase in the number of single-person households has resulted in many changes in diet as well as social environment, such as the increasing reliance on processed and instant foods and nutrient imbalance.[78] In case of the elderly population, social support is an important factor [9] because they find it difficult to prepare or purchase a meal on their own and they may feel lonely. Therefore, nutrition consumption differed significantly between elderly people living with family members who prepare their meals and elderly people who live alone; elderly people living alone were more likely to be exposed to nutritional risk than elderly people living with family members.[10] A study that compared between single-person households and family households reported that intake of protein-rich foods and fruits was low among single-person households [11] and households with several members; another study reported that presence or absence of a spouse affected food intake.[12] In addition, a high rate of eating breakfast and eating out alone whereas a low rate of fish and seafood consumption was reported.[11] According to a previous study on health status of household members according to type of household, elderly people living alone had more than one chronic disease; a single elderly person was less healthy compared to an elderly person living with their family. They also showed poor health behaviors related to obesity, drinking, and smoking.[13]

Rapid aging of the Korean population and increase in number of single-person households will continue in the future; thus, an in-depth analysis is highly needed. The purpose of this study was to analyze the dietary and health status of elderly people according to type of household and to provide basic data for effective management of health-related problems.

In Korea, due to social problems such as nuclear family, increase of economic activity of women, marital avoidance phenomenon, and population aging, the number of single-person households has increased, and the type of household has been diversified and dietary problems have been raised. Therefore, in this study, we tried to analyze the health and dietary status of the elderly by using the data of the 6th KNHANES (2013–2014). The proportion in single-person household was higher for women, older people, unmarried people, and lower economic and income levels. In the previous studies analyzing the characteristics of households, the unmarried ratio of single male household was high and the low income ratio was high in single female household.[15] Although this study did not compare gender, it may have been influenced by the slightly higher proportion of women in this study.

There were many differences in the comparison of the disease status and health status according to household type. The prevalence of chronic diseases was higher in single-person households, which is the same as in the previous study.[13] In the Won and Choi [16] among the single-person households, the young people reported that their health status was better and the gap was the largest in the middle-aged. The rate of people who think that single-person household is unhealthy is higher and the death rate is higher.[17] In a study of elderly people, the number of chronic illnesses and the rate of 2 or more diseases were significantly higher in single-person household.[18] A single-person household is more likely to have polarization, aging, and femininity than general households.[19] Therefore, adults who live alone in an overly competitive society are exposed to various health problems caused by poor health habits such as irregular life, unbalanced diet, excessive stress, smoking and drinking.

In the survey on health behavior, the low smoking and drinking rate is due to the high percentage of women in this study. The perception of health and the QOL were lower in single-person households. The QOL is influenced by factors such as economic income, health level, and psychological status. It seems reasonable that the QOL is low because single-person households was poor than the family households.[20]

A comparison of nutritional quality indices revealed that the nutrient intake of single-person household was inadequate. The intake of sodium was excessive and the intake of calcium and riboflavin was particularly insufficient. This was similar to the previous study in which vitamin D, riboflavin, and calcium in the elderly were inadequately consumed.[21] The elderly often prefer to salty food, a high carbohydrate intake, and maintain a diet that lacks calcium intake. Most single-person households do not purchase food, but most of them have a high rate of eating out or buying cooked food. In addition, the regular meal rate was low and satisfaction of their diet habit was low.[22]

In the survey on food insecurity, it was found that 14.1% of single-person households did not eat enough food sometimes due to economic factors, and 3.7% of them did not often eat food. There was also a higher rate of having worried about eating food without eating it because it lacked money. In other studies, it was reported that the lower the food stability, the lower the nutrient intake and the higher the energy density, and the effective factor influencing the food insecurity was the household income.[23] In other studies, the intake of vitamins and minerals was lower in single-person household and the nutrient intake was affected by the season in the elderly group.[12]

The reason for the higher food insecurity of single-person households compared to those living together is that they are responsible for the economic burden alone. Therefore, single-person households with low income are more likely to experience food insecurity.

This study has some limitations. First, the causal analysis of the factors affecting the health of single-person households was not conducted and only cross-sectional analysis was conducted. The age and sex of the subjects were not subdivided into multiple angles. It is also regrettable that age-specific comparisons were not performed because only the elderly were analyzed. A comparative study of insufficient food intake and sarcopenia is also expected to be conducted in the future. However, it has significance in analyzing the national health statistics of Korea and analyzing the health and nutritional status of the elderly living alone.

In this study, the elderly living alone in Korea had higher chronic disease prevalence, lower QOL, and unbalanced nutritional status than the elderly living with their families. More research should be done, and various factors should be considered for the health of the elderly.