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Table 2 Rate of invasive breast cancer among postmenopausal women (50-79 years old) enrolled in the Women's Health Initiative Observational Study (1993-2003)

From: Family history of later-onset breast cancer, breast healthy behavior and invasive breast cancer among postmenopausal women: a cohort study

Number of breast healthy behaviors participated in FHLBC Cases Woman-years Rate (per 10,000 woman-years) Rate difference Attributable proportion
All three Yes 25 4,206 59 24 41%
  No 108 30,807 35   
Two Yes 95 17,136 55 14 25%
  No 544 130,438 42   
One Yes 182 29,020 63 23 36%
  No 901 225,716 40   
None Yes 25 3,585 70 23 33%
  No 117 25,002 47   
  1. The women are stratified by family history of breast cancer (in a first-degree relative at the age of 45 years or more) and the degree of participation in behaviors recommended for breast cancer-preventive behaviors. To focus on the comparison of greatest contrast, women exhibiting partial adherence were excluded from the following calculation: interaction contrast = [RBHB = all three, FHLBC = 1 - RBHB = all three, FHLBC = 0] - [RBHB = none, FHLBC = 1 - RBHB = none, FHLBC = 0] = 0.0001; 95% confidence interval = -0.0036, 0.0039. FHLBC, family history of later-onset breast cancer.