Table 1.

Comparison of general information

Item	Observation group (n=40)	Control group (n=40)	t/χ2	P
Age (year old)	71.5±11.5	72.0±12.0	0.190	0.850
Gender (male/female)	27/13	25/15	0.050	0.815
Course of disease (month)	13.3±2.6	14.1±3.4	1.251	0.215
Hypertension	4	6	0.114	0.735
Diabetes mellitus	7	3	1.029	0.310
K-L grade			0.469	0.494
II	18	14
III	22	26
BMI (kg/m2)	23.8±2.9	24.2±3.1	0.596	0.553

Note: BMI: body mass index; K-L: Kellgren-Lawrence.