Table I.

General data of the patients and the controls.

Items	Observation group (n=112)	(n=342)	Control group t/χ2 value	P-value
Sex (male/female)	59/53	174/168	0.049	0.824
Age (years)	20–59	20–60
Average age (years)	68.85±7.89	68.37±7.48	0.581	0.562
Body mass index (kg/m2)	23.55±2.37	23.42±2.53	0.479	0.632
Educational level
Junior high school and below	15 (13.39)	43 (12.57)	0.102	0.951
Senior high school and technical secondary school	59 (52.68)	178 (52.05)
Junior college and above	38 (33.93)	121 (35.38)