Table 1.

Distribution of demographic characters among cases and controls.

	Cases		Controls		p-Value
	N	%	N	%
Gender
Male	159	77.9	287	69.2	0.0221
Female	45	22.1	128	30.8
Age
<40	31	15.2	31	7.5	0.0003
40-50	54	26.5	69	16.6
50-60	54	26.5	136	32.8
60-70	42	20.6	116	28.0
≥70	23	11.3	63	15.2
Education
Illiteracy	44	21.6	73	17.6	0.0018
Primary school	77	37.8	142	34.2
Middle school	70	34.3	124	29.9
High school	13	6.4	66	15.9
College and above	0	0.0	10	2.4
Monthly income per capita (Yuan)
<60	63	30.9	88	21.2	0.0643
60-100	35	17.2	74	17.8
100-160	58	28.4	135	32.5
≥160	48	23.5	118	28.4
BMI
≤22	106	52.0	180	43.4	0.0440
>22	98	48.0	235	56.6