Table 2.
HRs (95% CIs) for breast cancer incidence (n = 5,676) by quintile of estimated exposure for individual mammary gland carcinogenic compounds and summary MGC variable
| Quintile of concentration | ||||||
|---|---|---|---|---|---|---|
| Compound | Quintile 1 | Quintile 2 | Quintile 3 | Quintile 4 | Quintile 5 | P trend |
| Acrylamide | 1 (Referent) | —a | 1.02 (0.94, 1.10) | 1.09 (1.02, 1.17) | 1.08 (1.01, 1.16) | 0.008 |
| Acrylonitrile | 1 (Referent) | 1.03 (0.95, 1.12) | 1.02 (0.94, 1.11) | 1.05 (0.97, 1.14) | 1.06 (0.97, 1.15) | 0.17 |
| Benzene | 1 (Referent) | 1.09 (1.00, 1.18) | 1.03 (0.95, 1.12) | 1.03 (0.95, 1.12) | 1.06 (0.98, 1.16) | 0.38 |
| Benzidine | 1 (Referent) | —a | 0.98 (0.86, 1.12) | 0.97 (0.91, 1.04) | 1.06 (0.99, 1.14) | 0.24 |
| 1,3-Butadiene | 1 (Referent) | 0.98 (0.91, 1.07) | 1.06 (0.98, 1.15) | 0.99 (0.91, 1.08) | 1.02 (0.94, 1.11) | 0.56 |
| Carbon tetrachloride | 1 (Referent) | 0.98 (0.90, 1.07) | 1.04 (0.96, 1.13) | 1.03 (0.95, 1.12) | 1.08 (1.00, 1.18) | 0.03 |
| Chloroprene | 1 (Referent) | —a | —a | 1.05 (0.96, 1.15) | 1.07 (1.00, 1.14) | 0.04 |
| 1,4-Dioxane | 1 (Referent) | 1.04 (0.96, 1.13) | 1.05 (0.96, 1.14) | 1.07 (0.99, 1.16) | 1.02 (0.94, 1.11) | 0.23 |
| Ethyl carbamate | 1 (Referent) | —a | —a | 0.97 (0.90, 1.05) | 1.07 (1.00, 1.14) | 0.22 |
| Ethylene dibromide | 1 (Referent) | 1.05 (0.97, 1.14) | 1.07 (0.99, 1.16) | 1.03 (0.95, 1.12) | 1.01 (0.93, 1.10) | 0.88 |
| Ethylene dichloride | 1 (Referent) | 1.04 (0.95, 1.12) | 0.94 (0.86, 1.02) | 1.04 (0.96, 1.13) | 1.05 (0.97, 1.14) | 0.25 |
| Ethylene oxide | 1 (Referent) | 0.93 (0.85, 1.00) | 0.92 (0.85, 1.00) | 0.97 (0.89, 1.05) | 1.00 (0.92, 1.08) | 0.70 |
| Ethylidene dichloride | 1 (Referent) | 1.01 (0.93, 1.10) | 1.09 (1.00, 1.18) | 1.08 (0.99, 1.17) | 1.02 (0.94, 1.11) | 0.19 |
| Hydrazine | 1 (Referent) | —a | 0.92 (0.86, 0.99) | 0.98 (0.91, 1.06) | 1.04 (0.97, 1.12) | 0.36 |
| Methylene chloride | 1 (Referent) | 0.97 (0.89, 1.05) | 1.06 (0.98, 1.15) | 1.01 (0.93, 1.10) | 1.04 (0.96, 1.13) | 0.21 |
| 4,4'-Methylene bis(2-chloroaniline) | 1 (Referent) | —a | —a | 1.02 (0.92, 1.13) | 1.07 (1.01, 1.15) | 0.03 |
| Nitrobenzene | 1 (Referent) | —a | —a | 1.04 (0.97, 1.12) | 1.03 (0.96, 1.10) | 0.29 |
| Propylene dichloride | 1 (Referent) | 1.00 (0.92, 1.08) | 0.92 (0.85, 1.01) | 1.01 (0.93, 1.09) | 1.04 (0.96, 1.13) | 0.20 |
| Propylene oxide | 1 (Referent) | 1.05 (0.97, 1.15) | 1.11 (1.02, 1.20)* | 1.05 (0.97, 1.14) | 1.01 (0.93, 1.10) | 0.18 |
| Styrene | 1 (Referent) | 1.04 (0.96, 1.13) | 1.02 (0.94, 1.11) | 1.05 (0.96, 1.14) | 1.04 (0.96, 1.13) | 0.41 |
| 2,4-Toluene diisocyanate | 1 (Referent) | 1.05 (0.96, 1.14) | 1.04 (0.96, 1.13) | 1.03 (0.95, 1.12) | 1.07 (0.98, 1.16) | 0.17 |
| o-Toluidine | 1 (Referent) | —a | —a | 1.10 (1.01, 1.21) | 1.03 (0.97, 1.10) | 0.10 |
| Vinyl chloride | 1 (Referent) | 1.03 (0.94, 1.12) | 1.12 (1.03, 1.21)* | 1.07 (0.99, 1.17) | 1.06 (0.98, 1.16) | 0.06 |
| Vinylidene chloride | 1 (Referent) | 0.97 (0.90, 1.06) | 0.98 (0.90, 1.07) | 1.04 (0.96, 1.13) | 1.03 (0.94, 1.11) | 0.27 |
| Summary variable | 1 (Referent) | 0.98 (0.90, 1.07) | 0.97 (0.89, 1.05) | 1.02 (0.94, 1.10) | 1.05 (0.96, 1.14) | 0.11 |
Models stratified by age and adjusted for race. Quintiles based on distribution of all study participants.
aQuintiles combines when a larger portion of the study participants had same concentration value.
*Remains statistically significant (p < 0.05) after adjustment for multiple comparisons.