Table 3

Observed number of exposed cases and controls and OR with 95% CI for breast cancer before and after the age of 50 years in Danish women by proxies for occupational UVR exposure

	<50 years				≥50 years
	Cases	Controls	OR*	95% CI	Cases	Controls	OR*	95% CI
Overall	3319	16 125	1.02	0.98 to 1.07	4506	22 808	0.97	0.94 to 1.01
Duration of exposure (years)
1–9	2674	13 071	1.02	0.97 to 1.07	3435	16 789	1.01	0.97 to 1.05
10–20	484	2218	1.08	0.97 to 1.19	629	3385	0.92	0.84 to 1.00
>20	161	836	0.94	0.80 to 1.12	442	2634	0.83	0.75 to 0.92
Trend test (p value)			0.25				0.00
Cumulative exposure†
>0%–25%	780	4016	0.96	0.89 to 1.04	1169	5674	1.01	0.95 to 1.08
>25%–50%	848	4046	1.05	0.97 to 1.13	1178	5722	1.01	0.95 to 1.08
>50%–75%	842	4031	1.04	0.96 to 1.12	1129	5707	0.97	0.91 to 1.04
>75%	849	4032	1.04	0.97 to 1.13	1030	5705	0.89	0.83 to 0.95
Trend test (p value)			0.08				0.01
Timing of first exposure‡
Prior to first live birth	2042	9748	1.05	1.00 to 1.11	2257	11 124	0.99	0.94 to 1.04
After first live birth	847	4456	1.01	0.94 to 1.10	1780	9327	0.96	0.91 to 1.01
Exposure in last held job§
No	2440	11 922	1.01	0.97 to 1.06	3531	17 898	0.97	0.93 to 1.01
Yes	879	4203	1.04	0.97 to 1.13	975	4910	0.98	0.91 to 1.05

*Adjusted for parity, age at first live birth and work-related physical activity.
†Exposure level*years summed over employment history and categorised according to percentiles among the controls.
‡Among parous women.
§Among women with lifetime occupational UVR exposure.
UVR, ultraviolet B radiation.