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Table 1 Characteristics of cases and controls whose Cape Cod residences were served by public water supplies.

From: Breast cancer risk and drinking water contaminated by wastewater: a case control study

Characteristic Cases (n = 824) No. (%) Controls (n = 745) No. (%) Adjusted OR (95% CI)a
Family history of breast cancerb
   No 620 (75) 602 (81) 1.0 (reference)
   Yes 204 (25) 143 (19) 1.4 (1.1 – 1.7)
Age at birth of first child
   Under 30 510 (62) 530 (71) 1.0 (reference)
   Nulliparous, or 30+ 314 (38) 215 (29) 1.6 (1.3 – 2.0)
Prior breast cancer diagnosis
   No 761 (92) 680 (91) 1.0 (reference)
   Yes 63 (8) 65 (9) 0.8 (0.5 – 1.1)
Highest grade completed
   Less than high school graduate 54 (7) 75 (10) 0.6 (0.4 – 0.9)
   High school graduate 280 (34) 237 (32) 1.0 (reference)
   Some college/vocational 249 (30) 221 (30) 1.0 (0.7 – 1.2)
   College graduate 140 (17) 131 (18) 0.9 (0.7 = 1.3)
   Graduate study/degree 101 (12) 81 (11) 1.1 (0.8 – 1.6)
  1. a Adjusted for all other variables in the table and diagnosis/reference year, age at diagnosis/reference year, birth decade, study, and vital status
  2. b Breast cancer diagnosis in a mother, sister, or daughter.