Table 2.

Distribution of participants' demographic characteristics and their association with mammographic density for categorical variables

Data distribution, n (%)Mean (SE) of mammographic densityUnivariate regression adjusted for age*
Estimates (SE)P
Ethnicity
    Hispanic81 (34.32)33.28 (2.82)7.12 (4.70)0.05
    Anglo110 (46.61)37.49 (2.44)11.34 (4.55)
    Native American45 (19.07)26.16 (3.80)
Menopausal status
    Postmenopausal85 (36.64)26.14 (3.86)−12.71 (5.50)0.02
    Premenopausal147 (63.36)38.85 (2.61)
Parous status
    Yes117 (71.34)26.88 (2.34)−17.84 (4.50)0.0001
    No47 (28.66)44.71(3.76)
Ever taken birth control pills
    Yes40 (39.60)39.69 (4.32)11.13 (5.79)0.06
    No61 (60.40)28.56 (3.42)
Ever taken hormone replacement therapy
    Yes21 (21.21)37.11 (5.98)4.06 (6.81)0.55
    No78 (78.79)33.05 (3.02)
Family history of breast cancer
    Yes5 (5.15)37.51 (11.93)3.66 (12.26)0.77
    No92 (94.85)33.85 (2.74)
Breast size
    Small55 (23.40)49.64 (3.31)32.60 (4.90)<0.0001
    Medium136 (57.87)33.17 (2.03)16.13 (4.07)
    Large44 (18.72)17.05 (3.54)
  • * Univariate linear regression analysis of mammographic density against the corresponding demographic variables listed in the left column, adjusted for age.

  • Ps of overall effect for each variable.

  • Variables with missing data.