Objectives: Korea is one of the fastest-aging societies, and a large proportion of its older population lives alone. This study examined the impact of family interaction frequency on the association between living alone and depressive symptoms among older adults aged ≥80 years using nationally representative survey data. Methods: Among the 229 099 participants of the 2019 Korea Community Health Survey, 15 672 participants aged ≥80 years who either lived with close family or lived alone were included in the analysis. Participants living alone were classified according to the frequency of family interaction, ranging from less than once a month to more than once a week. The outcome variable was moderate to severe depressive symptoms, defined as a Patient Health Questionnaire-9 score of ≥10. Results: The prevalence of depressive symptoms was higher among older adults living alone (9.4–14.1%, depending on the frequency of family interaction) than among those living with close family (6.5%). Older adults living alone who interacted with family less than once a month were more likely to report depressive symptoms compared with those living with close family (adjusted odds ratio [aOR], 1.71; 95% confidence interval [CI], 1.36 to 2.15). Weekly family interaction mitigated the impact of living alone on the prevalence of depressive symptoms (aOR 1.10; 95% CI, 0.84 to 1.42). The influence of family interaction on the association between living alone and depressive symptoms remained consistent across subgroups of men, women, and those with difficulty in daily activities. Conclusions Encouraging regular interaction among family members could serve as an effective strategy to protect the mental health of older adults.

Purpose: This study aimed to evaluate and optimize microbial DNA extraction methods from urine, a non-invasive sample source, to enhance DNA quality, purity, and reliability for urinary microbiome research and biomarker discovery in bladder cancer. Materials and Methods: A total of 302 individuals (258 with genitourinary cancers and 44 with benign urologic diseases) participated in this study. Urine samples were collected via sterile catheterization, resulting in 445 vials for microbial analysis. DNA extraction was performed using three protocols: the standard protocol (SP), water dilution protocol (WDP), and chelation-assisted protocol (CAP). DNA quality (concentration, purity, and contamination levels) was assessed using NanoDrop spectrophotometry.Microbial analysis was conducted on 138 samples (108 cancerous and 30 benign) using 16S rRNA sequencing. Prior to sequencing on the Illumina MiSeq platform, Victor 3 fluorometry was used for validation. Results: WDP outperformed other methods, achieving significantly higher 260/280 and 260/230 ratios, indicating superior DNA purity and reduced contamination, while maintaining reliable DNA yields. CAP was excluded due to poor performance across all metrics. Microbial abundance was significantly higher in WDP-extracted samples (p<0.0001), whereas SP demonstrated higher alpha diversity indices (p<0.01), likely due to improved detection of low-abundance taxa. Beta diversity analysis showed no significant compositional differences between SP and WDP (p=1.0), supporting the reliability of WDP for microbiome research. Conclusions WDP is a highly effective and reliable method for microbial DNA extraction from urine, ensuring high-quality and reproducible results. Future research should address sample variability and crystal precipitation to further refine microbiome-based diagnostics and therapeutics.