TABLE 2.
Cox Proportional Hazards Ratios (HRs) for the Association of Education, Body Size, and Breast Cancer Incidence Among Postmenopausal White Women: CLUE II, Washington County, MD, 1989–2005
| Model 1 |
Model 2 |
|||
| Full Sample, HR (95% CI) | Subgroup, HR (95% CI) | Full Sample, HR (95% CI) | Subgroup, HR (95% CI) | |
| Education and BMI | ||||
| Education,a y | 1.06* (1.01, 1.11) | 1.06 (0.99, 1.13) | 1.06* (1.01, 1.11) | 1.06 (0.99, 1.13) |
| BMI,b kg/m2 | 1.03* (1.01, 1.05) | 1.03 (1.00, 1.06) | 1.03* (1.00, 1.05) | 1.03 (1.00, 1.06) |
| Education × BMI at baseline | 0.99 (0.99, 1.00) | 1.00 (0.99, 1.01) | ||
| Education and BMI at age 21 y | ||||
| Education,a y | 1.05* (1.00, 1.10) | 1.05 (0.98, 1.12) | 1.05* (1.00, 1.10) | 1.05 (0.99, 1.12) |
| BMI at age 21 y,c kg/m2 | 0.98 (0.94, 1.02) | 0.99 (0.94, 1.04) | 0.97 (0.93, 1.01) | 0.98 (0.93, 1.03) |
| Education × BMI at age 21 y | 0.98* (0.97, 0.99) | 0.98* (0.96, 1.00) | ||
| Education and BMI change | ||||
| Education,a y | 1.06* (1.01, 1.11) | 1.06 (0.99, 1.13) | 1.06* (1.019, 1.11) | 1.06 (0.99, 1.13) |
| BMI change,d kg/m2 | 1.04* (1.02, 1.07) | 1.04* (1.00, 1.07) | 1.04* (1.02, 1.07) | 1.04* (1.00, 1.07) |
| Education × BMI change | 1.00 (0.99, 1.01) | 1.01 (0.99, 1.02) | ||
Note. CI = confidence interval; BMI = body mass index. We adjusted full group models for age. We adjusted subgroup models for age, hormone use, age at first birth, number of live births, and breastfeeding. Analyses for Model 1 included education and body size measure; analyses for Model 2 included education, body size measure, and the interaction term.
a
Mean years of education = 11.7 years.
b
Mean BMI = 26.2 kg/m2.
c
Mean BMI at age 21 years = 21.2 kg/m2.
d
BMI change is the difference between BMI at baseline and BMI at age 21 years.
*
P < .05, 2 sided.