Table 2. Hazard ratios for melanoma, squamous cell carcinoma, and basal cell carcinoma according to cumulative UV flux.

	No. of cases (%)	Age-adjusted HR (95%CI)	Multivariable HR (95%CI)a
Melanoma (n=634 cases)
UV flux Q1b	88 (14)	0.66 (0.30, 1.47)	0.85 (0.36, 2.01)
UV flux Q2	130 (21)	1.07 (0.58, 1.96)	1.32 (0.68, 2.55)
UV flux Q3	112 (18)	0.89 (0.56, 1.41)	1.02 (0.63, 1.67)
UV flux Q4	129 (20)	1.01 (0.74, 1.38)	1.07 (0.78, 1.47)
UV flux Q5	175 (28)	1.00	1.00
P for trend	—	0.68	0.77
Per 200 × 10−4 RB units increasec	—	1.004 (0.966, 1.044)	0.979 (0.933, 1.028)
Squamous cell carcinoma (n=1065 cases)
UV flux Q1b	7 (1)	0.04 (0.01, 0.29)	0.05 (0.01, 0.35)
UV flux Q2	69 (6)	0.29 (0.17, 0.48)	0.34 (0.20, 0.59)
UV flux Q3	162 (15)	0.51 (0.37, 0.69)	0.57 (0.40, 0.79)
UV flux Q4	272 (26)	0.70 (0.57, 0.85)	0.74 (0.60, 0.91)
UV flux Q5	555 (52)	1.00	1.00
P for trend	—	<0.0001	<0.0001
Per 200 × 10−4 RB units increasec	—	1.069 (1.046, 1.092)	1.072 (1.041, 1.103)
Basal cell carcinoma (n=15 159 cases)
UV flux Q1b	152 (1)	0.41 (0.33, 0.52)	0.47 (0.37, 0.59)
UV flux Q2	2640 (17)	0.40 (0.36, 0.44)	0.45 (0.40, 0.51)
UV flux Q3	3505 (23)	0.59 (0.54, 0.64)	0.64 (0.58, 0.70)
UV flux Q4	3819 (25)	0.81 (0.76, 0.85)	0.84 (0.79, 0.89)
UV flux Q5	5043 (33)	1.00	1.00
P for trend	—	<0.0001	<0.0001
Per 200 × 10−4 RB units increasec	—	1.052 (1.045, 1.059)	1.043 (1.034, 1.052)

Abbreviations: CI=confidence interval; HR=hazard ratio; UV=ultraviolet.

^aMultivariable analyses adjusted for age, susceptibility to burn, ability to tan, natural hair colour at age 20, number of moles on left arm, family history of melanoma, severe sunburn counts, UV indices at state of residence at birth, 15 and 30 years of age, physical activity level, and rotating night shift.

^bUV flux quintiles: Q1=200–656, Q2=678–1294, Q3=1296–1872, Q4=1874–2614, and Q5=2616–5392 × 10⁻⁴ RB units, respectively.

^cCumulative UV flux was modelled as a continuous variable in the models.