Living Alone as a Persistent Risk Factor for Smoking and High-Risk Drinking: A Three-Year Repeated Cross-Sectional Analysis Before and During the COVID-19 Pandemic in the Republic of Korea.

Background

Single-person households have grown rapidly in the Republic of Korea and are consistently associated with higher rates of smoking and high-risk drinking. However, it remains unclear whether this vulnerability is structural and chronic or merely situational. This study examined whether the COVID-19 pandemic-a major societal disruption-altered the preexisting behavioral gap between single- and multi-person households.

Methods

We used repeated cross-sectional data from the Korea Community Health Survey (KCHS) for 2019 (unweighted n = 229,099), 2020 (unweighted n = 229,269), and 2021 (unweighted n = 229,242), representing weighted populations of approximately 43.0, 43.5, and 43.6 million adults aged ≥19 years, respectively. We applied complex sample logistic regression models including an interaction term between survey year and household type, adjusting for sex, age, income, and education.

Results

High-risk drinking significantly declined in both household types across all three time points following the COVID-19 pandemic, whereas smoking showed no significant overall change. Critically, the year x household type interaction was non-significant for high-risk drinking across all years; for smoking, a marginally significant interaction emerged only in 2021 (adjusted odds ratio [AOR] = 1.08, 95% CI: 1.01-1.16), suggesting a slight but limited divergence in the later pandemic period. Single-person households consistently showed higher odds of smoking (AOR = 1.65, 95% CI: 1.56-1.74) and high-risk drinking (AOR = 1.32, 95% CI: 1.25-1.39) across all three time points, relative to multi-person households and referenced to 2019 as the pre-pandemic baseline.

Conclusions

The health behavioral vulnerability of single-person households is structural and persistent, underscoring the need for household-structure-sensitive public health strategies to promote sustainable well-being.