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Table 1 Demographic Characteristics and Breast Cancer History of Female Kaiser Permanente Members Aged 40–65 in Marin County and East/Central Contra Costa County, California

From: Differences in reproductive risk factors for breast cancer in middle-aged women in Marin County, California and a sociodemographically similar area of Northern California

  Marin East/Central Contra Costa  
  Base No. Percent (95% CI) Base No. Percent (95% CI) p-value
Age 426   363   p < .053
   40 – 45 years   20.0 (15.9 – 24.1)   22.8 (18.3 – 27.4)  
   46 – 50 years   20.1 (16.4 – 23.9)   23.7 (19.3 – 28.2)  
   51 – 55 years   23.8 (19.8 – 27.8)   23.1 (18.7 – 27.6)  
   56 – 60 years   20.3 (16.4 – 24.2)   17.1 (13.1 – 21.1)  
   61 – 65 years   15.8 (12.4 – 19.1)   13.2 (10.2 – 16.2)  
Race/Ethnicity 423   361   p = .007
   Caucasian   88.3 (85.2 – 91.4)   84.3 (80.5 – 88.1)  
   African American   1.2 (0.1 – 2.2)   0.9 (<0.1 – 1.7)  
   Hispanic   4.9 (2.8 – 7.0)   3.7 (1.7 – 5.6)  
   Asian   4.2 (2.2 – 6.1)   10.8 (7.6 – 14.1)  
   Other   1.4 (0.3 – 2.5)   0.3 (<0.1 – 0.8)  
Ashkenazi Jewish heritage 416 12.8 (9.6 – 16.0) 357 7.1 (4.4 – 9.8) p = .012
Household income 405   345   p = .14
   ≤ $35, 000   11.6 (8.4 – 14.7)   6.3 (3.8 – 8.9)  
   > $35,000 to $50,000   10.2 (7.3 – 13.1)   9.9 (6.8 – 13.2)  
   > $50,000 to $80,000   26.0 (21.7 – 30.3)   27.2 (22.5 – 32.0)  
   > $80,000 to $100,000   17.6 (13.8 – 21.4)   17.2 (13.1 – 21.2)  
   > $100,000   34.6 (29.9 – 39.3)   39.1 (33.9 – 44.5)  
Education level 425   363   p = .47
   ≤High school grad   6.4 (4.1 – 8.7)   6.1 (3.6 – 8.5)  
   Some college/tech school   36.4 (31.8 – 41.0)   36.7 (31.7 – 41.8)  
   College graduate   30.2 (25.8 – 34.7)   34.5 (29.6 – 39.5)  
   Graduate degree   25.6 (21.4 – 29.8)   22.7 (18.2 – 27.1)  
History of breast cancer 425 5.0 (2.9 – 7.0) 363 4.6 (2.4 – 6.8) p = .77
First degree relatives with history of breast cancer 426   363   
   Daughter   1.1 (0 – 2.3)   0.6 (0 – 1.4) p = .61
   Mother   13.7 (10.2 – 17.3)   11.4 (7.9 – 14.9) p = .44
   Sister   3.6 (1.7 – 5.6)   4.4 (2.1 – 6.8) p = .56
   ≥ 1 first degree female relative   14.8 (11.4 – 18.2)   13.6 (10.0 – 17.2) p = .43
≥1 biopsy to check for cancer 425 21.8 (17.9 – 25.7) 363 17.2 (13.3 – 21.2) p = .12