Table IV.

Multivariate Cox proportional hazards models for the influences of ultraviolet B (UVB) phototherapy on skin cancer at different follow-up times

Follow-up time	Treatment with UVB phototherapy			Number of UVB phototherapy treatments
	HR	95% CI	p-value	HR	95% CI	p-value
3 years	0.832	0.319–2.172	0.71	1.004	0.984–1.025	0.68
6 years	0.844	0.376–1.894	0.68	1.003	0.982–1.023	0.81
9 years	1.074	0.557–2.071	0.83	1.003	0.987–1.018	0.74
12 years	1.129	0.616–2.068	0.70	1.002	0.986–1.018	0.82
15 years	1.068	0.585–1.950	0.83	1.001	0.984–1.018	0.89

Multivariate Cox proportional hazards models adjusted for the exposure variable of UVB phototherapy, age, sex, occupation, high Uv index, organ transplantation, and the prescription of hydrochlorothiazide at different follow-up times.

CI: confidence interval; HR: hazard ratio.