TABLE 2.

Association between frailty and incidence of depressive symptoms.

	HR (95% CI)		Per SD increase
	Robust	Pre-frailty/frailty
Frailty index
Unadjusted	1 (Reference)	1.39 (1.23–1.58)	1.24 (1.17–1.31)
Model 1	1 (Reference)	1.38 (1.22–1.57)	1.23 (1.16–1.30)
Model 2	1 (Reference)	1.38 (1.22–1.57)	1.23 (1.16–1.30)
Phenotypic frailty
Unadjusted	1 (Reference)	1.38 (1.21–1.56)	1.19 (1.12–1.26)
Model 1	1 (Reference)	1.38 (1.21–1.57)	1.19 (1.12–1.27)
Model 2	1 (Reference)	1.30 (1.14–1.48)	1.15 (1.08–1.22)

CI, confidence interval; HR, hazard ratio; SD, standard deviation. The crude model was conducted without any adjustment; Model 1 was adjusted for age, and sex; Model 2 was additionally adjusted for education level, smoking status, alcohol consumption, marital status, place of residence, income, participation in social activities, number of chronic diseases, retirement status, and sleep duration.