Table 2.

Characteristics of participants in this study.

Variable	Cases (N = 504)	Controls (N = 501)	p
Age (Years old)	48.46 ± 6.88	48.67 ± 8.01	0.308
≤44	130 (26%)	146 (29%)
45–59	351 (70%)	317 (74%)
≥60	23 (4%)	38 (7%)
Gender			0.920
Man	448 (89%)	447 (89%)
Woman	56 (11%)	54 (11%)
Drug-using time (Years)
>16	158 (31%)
≤16	141 (28%)
Absence	205 (41%)

SNP, single nucleotide polymorphism.