Breast cancer risk by exposure to organic solvents in a breast cancer case-control study
| Exposure metrics | Cases n=2383 | Controls n=2502 | OR* (95% CI) |
| n (%) | n (%) | ||
| Ever exposed to organic solvents | |||
| Never | 1961 (82.3) | 2093 (83.6) | |
| Ever | 422 (17.7) | 409 (16.4) | 1.16 (0.99 to 1.4) |
| Duration of exposure (in years)† | |||
| >0–5 | 123 (5.2) | 124 (5.0) | 1.17 (0.9 to 1.5) |
| >5–10 | 82 (3.4) | 72 (2.9) | 1.27 (0.9 to 1.8) |
| >10 | 217 (9.1) | 213 (8.5) | 1.13 (0.9 to 1.4) |
| p Trend¶ | 0.847 | ||
| Crude average intensity (quantity used in l/mo)† | |||
| ≥1–≤10 | 337 (14.2) | 313 (12.5) | 1.18 (0.99 to 1.4) |
| >10–≤100 | 77 (3.2) | 77 (3.1) | 1.23 (0.9 to 1.7) |
| >100 | 8 (0.3) | 19 (0.8) | 0.61 (0.3 to 1.4) |
| p Trend¶ | 0.368 | ||
| Intensity weighted by duration (in l/mo)† | |||
| ≥1–≤10 | 336 (14.1) | 317 (12.7) | 1.16 (0.98 to 1.4) |
| >10–≤100 | 78 (3.3) | 73 (2.9) | 1.31 (0.9 to 1.8) |
| >100 | 8 (0.3) | 19 (0.8) | 0.61 (0.3 to 1.4) |
| p Trend¶ | 0.590 | ||
| Crude average frequency (h/wk)† | |||
| ≥1–<2 | 33 (1.4) | 20 (0.8) | 1.91 (1.1 to 3.4) |
| ≥2–≤10 | 133 (5.6) | 110 (4.4) | 1.16 (0.9 to 1.5) |
| >10–<20 | 169 (7.1) | 185 (7.4) | 1.06 (0.8 to 1.3) |
| ≥20 | 87 (3.6) | 94 (3.8) | 1.23 (0.9 to 1.7) |
| p Trend¶ | 0.368 | ||
| Average frequency weighted by duration (h/wk)† | |||
| ≥1–<2 | 35 (1.5) | 20 (0.8) | 2.00 (1.1 to 3.5) |
| ≥2–≤10 | 134 (5.6) | 112 (4.5) | 1.16 (0.9 to 1.5) |
| >10–<20 | 165 (6.9) | 182 (7.3) | 1.05 (0.8 to 1.3) |
| ≥20 | 88 (3.6) | 95 (3.8) | 1.23 (0.9 to 1.7) |
| p Trend¶ | 0.305 | ||
| Average latency (years)† | |||
| 0–15 | 41 (1.7) | 34 (1.4) | 1.48 (0.9 to 2.4) |
| >15 | 381 (16.0) | 375 (15.0) | 1.14 (0.97 to 1.3) |
| p Trend¶ | 0.266 | ||
| Cumulative exposure (h*l*years/wk*mo)†,‡ | |||
| >0–39 | 213 (8.9) | 206 (8.2) | 1.19 (0.96 to 1.5) |
| >39 | 209 (8.8) | 203 (8.1) | 1.15 (0.9 to 1.4) |
| p Trend¶ | 0.741 | ||
| Highest intensity*frequency (l*h/mo*wk)†,§ | |||
| I level | 321 (13.5) | 298 (11.9) | 1.19 (0.99 to 1.4) |
| II level | 101 (4.2) | 111 (4.5) | 1.12 (0.8 to 1.5) |
| p Trend¶ | 0.776 | ||
| Crude average probability† | |||
| ≥1–<10% | 130 (5.5) | 128 (5.1) | 1.13 (0.9 to 1.5) |
| ≥10–<50% | 148 (6.2) | 134 (5.7) | 1.19 (0.9 to 1.5) |
| ≥50–<90% | 109 (4.6) | 113 (4.5) | 1.14 (0.9 to 1.5) |
| ≥90% | 35 (1.5) | 34 (1.4) | 1.31 (0.8 to 2.2) |
| p Trend¶ | 0.728 | ||
| Average probability weighted by duration† | |||
| ≥1–<10% | 130 (5.5) | 128 (5.1) | 1.13 (0.9 to 1.5) |
| ≥10–<50% | 146 (6.1) | 131 (5.2) | 1.19 (0.9 to 1.5) |
| ≥50–<90% | 108 (4.5) | 116 (4.6) | 1.11 (0.8 to 1.5) |
| ≥90%ss | 38 (1.6) | 34 (1.4) | 1.44 (0.9 to 2.3) |
| p Trend¶ | 0.674 | ||
↵* Adjusted for age, study site, education, body mass index (BMI), age at menarche, menopausal status, age at menopause (in postmenopausal women), number of full-term births, age at first full-term birth, breastfeeding, family history of breast cancer and previous screening mammography.
↵† Never exposed to organic solvents used as referent.
↵‡ Cumulative exposure: product of frequency, intensity, and duration of exposure summed across all jobs. Cutpoint=median in exposed controls.
↵§ Product of scores for intensity*frequency: I level=≤4, II level=>4.
↵¶ p For trend in ever exposed to organic solvents.