Table 2.

Linear mixed-effects models ^a of the effects of group and time, and their interaction, on the outcome variables

	Primary outcome			Secondary outcomes
	SGDS-K b			LSNS-K d	S-IADL e	MMSE-KC f
	Total	Baseline fewer depressive symptoms c	Baseline more depressive symptoms c
Main effect of group	5.00* (1, 152)	9.55 (1, 119)	2.04 (1, 28)	8.18* (1, 153)	0.04 (1, 153)	1.76 (1, 153)
Main effect of time	0.08 (1, 151)	7.00 (1, 119)	4.58* (1, 28)	8.38* (1, 153)	5.48* (1, 153)	1.91 (1, 153)
Group × time interaction effect	0.49 (1, 151)	5.85* (1, 119)	1.14 (1, 28)	5.29* (1, 153)	0.55 (1, 153)	0.25 (1, 153)

*p < 0.05

^a The linear mixed models included the factors of group and time, and the group × time interaction, with adjustment for age, sex, years of education, and type of medical insurance. Data are F statistics (numerator and denominator degrees of freedom)

^b Korean version of the Geriatric Depression Scale – Short Form; a higher score corresponds to more depressive symptoms (range: 0–15)

^c Participants were stratified by baseline SGDS-K scores (< 6 vs. ≥ 6)

^d Korean version of the Lubben Social Network Scale; a higher score corresponds to a stronger social network (range: 0–50)

^e Seoul Instrumental Activities of Daily Living; a higher score corresponds to worse daily function (range: 0–45)

^f Mini-Mental State Examination; part of the neuropsychological battery of the Consortium to Establish a Registry for Alzheimer’s Disease; a higher score corresponds to better global cognitive function (range: 0–30)