Table IV.
Residential and personal measures of sun exposure in breast cancer cases and controls from the U.S. Radiologic Technologists cohort.
| Controls n (%) | Cases n (%) | Estimates of association | ||
|---|---|---|---|---|
| Odds ratio (95% confidence interval) | Ptrend | |||
| Geographic region at study baseline (%) | 0.90 | |||
| Northwestern U.S. (including Alaska) | 179 (21.2) | 105 (21.7) | 1.00 (ref) | |
| Northeastern U.S. | 289 (34.2) | 160 (33.1) | 0.89 (0.63-1.25) | |
| Southwestern U.S. (including Hawaii) | 200 (23.7) | 108 (22.3) | 0.84 (0.58-1.22) | |
| Southeastern U.S. | 177 (21.0) | 111 (22.9) | 1.04 (0.71 -1.51) | |
|
| ||||
| Annual ambient sunlight in state of residence at study baseline in Robertson-Berger units (RB, joules/m2) | 0.46 | |||
| ≤ 109 | 203 (25.0) | 122 (26.1) | 1.00 (ref) | |
| 110 – 118 | 212 (26.1) | 121 (25.9) | 1.00 (0.70-1.43) | |
| 118 – 146 | 195 (24.0) | 121 (25.9) | 1.04 (0.73-1.49) | |
| >147 | 202 (24.9) | 103 (22.1) | 0.85 (0.58-1.22) | |
|
| ||||
| Annual ambient sunlight in state of residence at birth (RB, joules/m2) | 0.07 | |||
| ≤ 109 | 242 (29.8) | 167 (35.5) | 1.00 (ref) | |
| 110 – 118 | 267 (32.8) | 140 (29.8) | 0.84 (0.61 - 1.15) | |
| 118 – 146 | 150 (18.5) | 94 (20.0) | 0.85 (0.59-1.22) | |
| >147 | 154 (18.9) | 69 (14.7) | 0.69 (0.47-1.01) | |
|
| ||||
| Weekly hours spent outdoors during summer in childhood (age <13 years) | 0.74 | |||
| ≤ 12 | 166 (25.0) | 98 (26.9) | 1.00 (ref) | |
| 12-24.5 | 252 (38.0) | 144 (39.6) | 0.86 (0.60 - 1.24) | |
| 24.5-34.5 | 85 (12.8) | 34 (9.3) | 0.60 (0.35-1.02) | |
| >34.5 | 161 (24.3) | 88 (24.2) | 0.97 (0.65-1.45) | |
|
| ||||
| Weekly hours spent outdoors during summer in adolescence (age 13 to 19 years) | 0.60 | |||
| ≤ 10.5 | 209 (31.5) | 121 (33.5) | 1.00 (ref) | |
| 10.6-18.4 | 124 (18.7) | 59 (16.3) | 0.78 (0.53-1.14) | |
| 18.5-28.5 | 211 (31.8) | 124 (34.4) | 1.01 (0.73-1.38) | |
| ≥28.6 | 120 (18.1) | 57 (15.8) | 0.82 (0.56-1.21) | |