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Table 2 Associations between wastewater impacted public drinking water and breast cancer.

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.
   
  1. a Adjusted for diagnosis/reference year, age at diagnosis/reference year, birth decade, study, vital status, previous breast cancer diagnosis, age at first birth, family history of breast cancer, and education.
  2. b Adjusted for variables in analysis (a), years on Cape Cod and years on the Cape squared.