From: Breast cancer risk and drinking water contaminated by wastewater: a case control study
 | Cases | Controls | Adjusted OR (95% CI)a | Adjusted OR (95% CI)b |
---|---|---|---|---|
Average annual excess nitrate-N concentration (mg/L) | ||||
0 to < .3 | 327 | 287 | 1.0 (reference) | 1.0 (reference) |
.3 to < .6 | 201 | 175 | 1.0 (0.7 – 1.3) | 0.9 (0.7 – 1.3) |
.6 to < .9 | 155 | 152 | 0.9 (0.6 – 1.2) | 0.8 (0.6 – 1.1) |
.9 to < 1.2 | 120 | 112 | 0.9 (0.6 – 1.2) | 0.9 (0.6 – 1.2) |
≥ 1.2 | 21 | 19 | 0.9 (0.5 – 1.7) | 1.0 (0.5 – 1.9) |
Sum of annual excess nitrate-N concentrations (mg/L) | ||||
0 to < .01 | 19 | 18 | 0.8 (0.4 – 1.6) | 0.9 (0.5 – 1.9) |
.01 to < .1 | 45 | 42 | 0.9 (0.6 – 1.5) | 1.1 (0.7 – 1.7) |
.1 to < 1 | 119 | 118 | 0.9 (0.7 – 1.2) | 1.1 (0.8 – 1.5) |
1 to < 10 | 474 | 418 | 1.0 (reference) | 1.0 (reference) |
≥ 10 | 167 | 149 | 1.0 (0.8 – 1.3) | 0.9 (0.7 – 1.2) |
Number of years exposed to excess nitrate-N > 1 mg/L | ||||
0 | 562 | 504 | 1.0 (reference) | 1.0 (reference) |
< 2 | 58 | 52 | 1.0 (0.7 – 1.5) | 1.1 (0.7 – 1.6) |
2 to < 4 | 93 | 77 | 1.0 (0.7 – 1.4) | 1.0 (0.7 – 1.4) |
4 to < 6 | 36 | 44 | 0.8 (0.5 – 1.2) | 0.7 (0.5 – 1.2) |
6 to < 8 | 50 | 43 | 1.0 (0.6 – 1.5) | 0.9 (0.6 – 1.4) |
≥ 8 | 25 | 25 | 0.9 (0.5 – 1.7) | 0.9 (0.5 – 1.5) |
OR odds ratio. CI confidence interval. | Â | Â | Â |