Table 3.

Associations between predictor variables and percentage of breast density

Predictor variablesAll (n = 412)
Premenopausal (n = 206)
Postmenopausal (n = 206)
raPbraPbraPb
Age (yrs)−0.422 × 10−190.030.7−0.322 × 10−6
Height (inches)0.090.30.020.70.090.4
Weight (pounds)−0.352 × 10−14−0.411 × 10−9−0.322 × 10−6
BMI (kg/m2)−0.402 × 10−17−0.432 × 10−10−0.382 × 10−8
Age at menopausec (yrs)0.070.08
Age at menarche (yrs)0.050.80.100.30.020.6
Age at first birthd (yrs)0.070.30.140.2−0.040.9
  • Note: Data presented for women included in the mammogram-gene analysis.

  • a Pearson correlation coefficient (unadjusted).

  • b P value for trend (generalized linear model) adjusted for age (yrs, continuous) and BMI (kg/m2, continuous). Height, weight, and BMI versus breast density were adjusted for age only. Age versus breast density was unadjusted.

  • c Age at menopause only includes women who had natural menopause or bilateral oophorectomy.

  • d Age at first birth of parous women.