Table 1.

Characteristics of the participants according to depressive symptoms

Characteristics	Total Sample, n = 940	Depression, n = 303	No Depression, n = 637	P
Serum vitamin D, ng/mL, mean ± SD	22.7 ± 9.5	20.8 ± 8.7	23.7 ± 9.7	<  0.001
Vitamin D deficiency, %	39.8%	47.9%	35.9%	<  0.001
Age, mean ± SD	102.5 ± 2.7	102.5 ± 2.8	102.5 ± 2.7	0.802
Females, %	81.4%	89.8%	77.4%	<  0.001
Han ethnic, %	87.9%	87.5%	88.1%	0.432
Illiterate, %	91.0%	95.7%	88.7%	<  0.001
Living with families, %	85.7%	84.8%	86.2%	0.618
Relatives contacts, %	43.7%	39.9%	51.8%	0.001
Friends contacts, %	33.7%	32.0%	37.3%	0.121
BMI, kg/m2, mean ± SD	18.3 ± 3.2	17.8 ± 3.3	18.5 ± 3.1	0.004
SBP, mmHg, mean ± SD	152.1 ± 24.7	152.9 ± 25.5	151.7 ± 24.4	0.504
DBP, mmHg, mean ± SD	75.5 ± 13.2	75.2 ± 13.7	75.7 ± 12.9	0.538
TG, mmol/L	1.17 ± 0.67	1.18 ± 0.83	1.16 ± 0.58	0.615
TC, mmol/L, mean ± SD	4.66 ± 1.04	4.58 ± 1.05	4.70 ± 1.04	0.105
FBG, nmol/L, mean ± SD	4.87 ± 1.88	5.00 ± 1.77	4.81 ± 1.92	0.131
ALB, g/L, mean ± SD	38.4 ± 4.1	37.8 ± 4.2	38.7 ± 4.0	0.002
Hb, g/L, mean ± SD	113.2 ± 16.8	110.5 ± 17.3	114.4 ± 16.3	0.001
Estimated GFR, ml/min per 1.73m2, mean ± SD	75.8 ± 28.5	77.1 ± 29.2	75.2 ± 28.2	0.358
Current smoker, %	3.5%	3.3%	3.6%	0.488
Current alcohol drinker, %	10.6%	8.6%	11.6%	0.096
Current tea drinker, %	12.1%	11.2%	12.6%	0.318
Frequent milk drinking, %	26.3%	29.0%	25.0%	0.205
Frequent fish intake, %	63.5%	62.4%	64.1%	0.664
Frequent fruit intake, %	58.9%	61.7%	57.6%	0.256
ADL impairments, %	56.4%	72.3%	48.8%	<  0.001
Outdoor activities > 1 h/d, %	59.6%	52.5%	63.0%	0.001
Visual impairments, %	28.0%	28.4%	27.8%	0.454
Auditory impairments, %	31.2%	30.4%	31.6%	0.386

Abbreviation: SD standard deviation, BMI body mass index, SBP systolic blood pressure, DBP diastolic blood pressure, TG triglyceride, TC total cholesterol, FBG fasting blood glucose, ALB albumin, Hb hemoglobin, GFR estimated glomerular filtration rate, ADL activity of daily living