Serum cystatin C, impaired kidney function, and geriatric depressive symptoms among older people living in a rural area: a population-based study

Table 3 Longitudinal associations of serum cystatin C and impaired kidney function with incident geriatric depressive symptoms (n = 669)

Serum cystatin C or impaired kidney function	N/n	Hazard ratio (95% confidence interval)
Serum cystatin C or impaired kidney function	N/n	Model 1^a	Model 2^a	Model 3^a
Cystatin C, mg/L
≤ 1.00	388/78	1.00 (reference)	1.00 (reference)	1.00 (reference)
1.01–1.25	175/40	1.11 (0.75–1.65)	1.22 (0.82–1.81)	1.21 (0.81–1.80)
> 1.25	106/39	2.20 (1.48–3.27)	2.23 (1.48–3.34)	2.16 (1.43–3.27)
p for linear trend		0.001	0.001	0.001
Impaired kidney function
No	544/122	1.00 (reference)	1.00 (reference)	1.00 (reference)
Yes	125/35	1.57 (1.06–2.32)	1.57 (1.05–2.34)	1.54 (1.03–2.30)

N/n indicates number of subjects/number of persons with depressive symptoms
Abbreviations: MMSE mini-mental state examination, ADL activities of daily living
^aModel 1 was adjusted for age, sex, and education; model 2 was additionally adjusted for alcohol consumption, hypertension, stroke, heart disease, cataract, chronic obstructive pulmonary disease, nephritis, and arthritis; and in model 3, MMSE score and ADL-disability were added to model 2