Changes in Household Size in the Republic of Korea and Depression: A Temporal Analysis

Abstract

Introduction Prevailing socioeconomic processes, such as marriage patterns and procreation, differences in intergenerational norms, the demand for education and health care, spending priorities, and consumption patterns, can have an impact on household size and composition. Over the past few decades, the average household size has decreased in most countries, and it is common for individuals to live alone.

However, a decrease in household size has been associated with health effects, particularly poor mental health, and depression, in addition to several socioeconomic consequences. Despite these important observations, these studies are limited as they were mainly conducted as cross-sectional studies in a small number of Western countries. Therefore, there is a need for studies that examine the change in household size and the presence or absence of depression in a time-lined manner, especially in Asian cultures. The purpose of this study was to examine the relationship between changes in household size and depression through a temporal analysis using panel data from a sample of the Korean population.

Methods This study used data from the Korean Welfare Panel Study (KOWEPS)—a nationally representative panel survey of the Korean population—from 2010 to 2019, and an exhaustive description of the KOWEPS sample has been published elsewhere.5 For the analysis, data regarding all individuals aged 25 years or above and only observations covering two consecutive years were retained because this study conceptualized a transition of household size as happening over 2 years (between years t – 1 and t). As the study used secondary data without personal identifiers, it was exempted from ethical approval by the Institutional Research Board at Ajou Medical Center (AJIRB-SBR-EXP-21-555).

The outcome variable was depressive symptoms, which were identified using the Center for Epidemiological Studies–Depression Scale (CES-D 11). The respondents were dichotomized as either displaying depressive symptoms (indicating a score of 16 or above) or not. The main explanatory variable in this study was the change in household size.

The number of household members at both t – 1 and t years was measured and then categorized into three groups: single-person households, two- or three-person households, and four-person or more households. The 2-year change in these three household sizes was represented by nine combinations. Potential confounding variables included sex, age group, education level, household income, employment status, self-esteem, and self-rated health. A generalized estimating equation (GEE) model was used to analyze the association between changes in household size and depression. All statistical analyses were conducted using SAS software version 9.4.

Results The results of the same analysis are presented in different reference groups (Table 1). Households that experienced an increase in size after a year showed a lower prevalence of depression. When a two- or three-person household changed to a four or more persons household, their probability of having depression was only 0.62 (95% confidence interval [CI] [0.50, 0.77]) times that of the reference group. When individuals in multi-person households inhabited single-person households after a year, the probability of their experiencing depression increased by more than 70% in comparison with those who remained in single-person households throughout (two or three > single: odds ratio [OR] = 1.72, 95% CI [1.51, 1.96], four or more > single: OR = 1.73, 95% CI [1.11, 2.69]).