Observed number of exposed cases (obs) and OR with 95% CI for subtypes of breast cancer, that is, by ER status, before and after the age of 50 years in Danish women by proxies for occupational UVR exposure
<50 years | ≥50 years | |||||||||||
ER− | ER+ | ER− | ER+ | |||||||||
Obs | OR* | 95% CI | Obs | OR* | 95% CI | Obs | OR* | 95% CI | Obs | OR* | 95% CI | |
Ever | 746 | 1.02 | 0.93 to 1.11 | 2112 | 1.06 | 0.99 to 1.11 | 641 | 0.97 | 0.88 to 1.06 | 3350 | 0.98 | 0.94 to 1.02 |
Duration of exposure (years) | ||||||||||||
1–9 | 596 | 1.00 | 0.90 to 1.10 | 1688 | 1.05 | 0.99 to 1.11 | 494 | 1.00 | 0.90 to 1.11 | 2543 | 1.01 | 0.97 to 1.06 |
10–20 | 114 | 1.14 | 0.93 to 1.41 | 311 | 1.11 | 0.98 to 1.26 | 87 | 0.97 | 0.77 to 1.23 | 472 | 0.91 | 0.82 to 1.00 |
>20 | 36 | 1.11 | 0.77 to 1.60 | 113 | 0.99 | 0.80 to 1.21 | 60 | 0.75 | 0.57 to 0.98 | 335 | 0.85 | 0.75 to 0.95 |
Trend test (p value) | 0.31 | 0.04 | 0.17 | 0.02 | ||||||||
Cumulative exposure† | ||||||||||||
>0%–25% | 159 | 0.87 | 0.73 to 1.04 | 502 | 1.00 | 0.90 to 1.10 | 166 | 1.00 | 0.83 to 1.17 | 872 | 1.02 | 0.94 to 1.10 |
>25%–50% | 187 | 1.03 | 0.87 to 1.21 | 531 | 1.08 | 0.98 to 1.19 | 178 | 1.07 | 0.88 to 1.24 | 879 | 1.03 | 0.95 to 1.11 |
>50%–75% | 200 | 1.10 | 0.93 to 1.28 | 544 | 1.08 | 0.98 to 1.19 | 154 | 0.92 | 0.74 to 1.07 | 841 | 0.98 | 0.91 to 1.06 |
>75% | 200 | 1.09 | 0.93 to 1.28 | 535 | 1.07 | 0.97 to 1.18 | 143 | 0.86 | 0.69 to 1.00 | 758 | 0.89 | 0.82 to 0.96 |
Trend test (p value) | 0.17 | 0.01 | 0.24 | 0.05 |
*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.
ER, oestrogen receptor; UVR, ultraviolet B radiation.