Table 1.

Descriptive statistics for 8108 study participants

Variables		Total	45–59	≥ 60
N		8108	4996	3112
Age (M ± SD)		57.48 ± 8.122	52.23 ± 4.411	65.89 ± 5.064
Gender	Male	3892 (48.0%)	2269 (45.4%)	1623 (52.2%)
	Female	4216 (52.0%)	2727 (54.6%)	1489 (47.8%)
Smoking	Yes	3186 (39.3%)	1836 (36.7%)	1350 (43.4%)
	No	4922 (60.7%)	3160 (63.3%)	1762 (56.6%)
Drinking	Drink more than once a month	2123 (26.2%)	1308 (26.2%)	815 (26.2%)
	Drink but less than once a month	657 (8.1%)	435 (8.7%)	222 (7.1%)
	None of these	5328 (65.7%)	3253 (65.1%)	2075 (66.7%)
Education	No formal education (illiterate)	1822 (22.5%)	960 (19.2%)	862 (27.7%)
	Elementary school or below	3398 (41.9%)	1829 (36.6%)	1569 (50.4%)
	Middle school school and above	2888 (35.6%)	2207 (44.2%)	681 (21.9%)
Marital status	Married with spouse present	7031 (86.7%)	4483 (89.7%)	2548 (81.9%)
	Married but not living with spouse temporarily for reasons such as work	336 (4.1)	261 (5.2%)	75 (2.4%)
	Separated	26 (0.3%)	10 (0.2%)	16 (0.5%)
	Divorced	52 (0.6%)	32 (0.6%)	20 (0.6%)
	Widowed	612 (7.5%)	179 (3.6%)	433 (14.9%)
	Never married	51 (0.6%)	31 (0.6%)	20 (0.6%)
FIT1		0.091 ± 0.070	0.081 ± 0.064	0.107 ± 0.075
FIT2		0.052 ± 0.055	0.046 ± 0.050	0.063 ± 0.061
FIT3		0.072 ± 0.063	0.064 ± 0.056	0.086 ± 0.070
FIT4		0.096 ± 0.082	0.083 ± 0.072	0.118 ± 0.091
DST1		8.13 ± 6.226	7.80 ± 6.117	8.68 ± 6.361
DST2		7.77 ± 5.750	7.68 ± 5.741	7.93 ± 5.762
DST3		8.01 ± 6.408	7.82 ± 6.330	8.32 ± 6.519
DST4		9.61 ± 8.061	9.19 ± 7.507	10.28 ± 8.837

Note M = mean; SD = Standard Deviation; FIT1 = frailty index in 2011; FIT2 = frailty index in 2013; FIT3 = frailty index in 2015; FIT4 = frailty index in 2018; DST1 = depressive symptoms in 2011; DST2 = depressive symptoms in 2013; DST3 = depressive symptoms in 2015; DST4 = depressive symptoms in 2018