Table 3.

Risk of Cervical Cancer among Metformin Users according to Cumulative Duration, Cumulative Dose, and Age

Variable	Hazard ratio (95% CI)a	Hazard ratio (95% CI)b
Cumulative duration, day
Non-users	1.000	-
0–469	1.603 (1.205–2.131)d	1.000
470–1,999	1.140 (0.931–1.396)c	0.723 (0.530–0.095)d
≥2,000	0.151 (0.093–0.243)c	0.094 (0.055–0.161)c
Cumulative dose, mg
Non-users	1.000	-
0–239,999	1.798 (1.376–2.349)c	1.000
240,000–1,200,000	0.849 (0.692–1.042)c	0.549 (0.356–0.642)c
>1,200,000	0.141 (0.077–0.258)c	0.079 (0.042–0.151)c
Age, yr
Non-users	1.000	-
<50	0.763 (0.481–1.252)d	-
≥50	0.791 (0.650–0.961)d	-

CI, confidence interval.

^aThe comparisons were made using metformin non-users as the reference group. The hazard ratios were adjusted for age, economic status, region of residence, and anti-diabetic medications (sulfonylureas, thiazolidinediones, dipeptidyl peptidase 4 inhibitors, alpha-glucosidase inhibitors, and meglitinide);

^bThe comparisons were made using a cumulative duration of 0–469 days or a cumulative dose of 0–239,999 mg as the reference groups. The hazard ratios were adjusted for age, economic status, region of residence, and anti-diabetic medications (sulfonylureas, thiazolidinediones, dipeptidyl peptidase 4 inhibitors, alpha-glucosidase inhibitors, and meglitinide);

^cP<0.001;

^dP<0.05.