Table 1.

Characteristics of postmenopausal women by NSAID use, Group Health, 1996-2006

CharacteristicsNonuser (n = 20,653), %Initiator (n = 5,978), %Discontinuer (n = 1,156), %Continuer (n = 838), %Mixed (n = 659), %P*
% Women in each category70.520.44.02.92.2
Age at first mammogram (y)
    ≤498.57.18.14.46.8<0.0001
    50-5938.330.433.324.426.6
    60-6928.927.929.027.928.1
    70-7918.926.923.632.730.2
    80-985.47.76.010.68.3
Age at second mammogram (y)
    ≤495.34.46.02.84.4<0.0001
    50-5935.327.830.222.125.0
    60-6930.528.429.525.926.4
    70-7921.428.225.234.031.9
    80-1007.511.29.115.212.3
Race
    White89.189.388.190.189.80.056
    Black6.96.97.05.65.3
    American Indian/Alaska Native2.12.33.02.93.3
    Asian/Hawaiian/Pacific Islander1.51.21.61.20.8
    Unknown0.40.30.30.20.8
Ethnicity
    Hispanic3.33.94.23.14.20.15
    Not Hispanic96.395.795.296.295.0
    Unknown0.40.40.60.70.8
BMI (at first mammogram)
    <2542.734.336.029.625.5<0.0001
    25-3030.532.230.531.630.3
    >3022.829.029.834.438.1
    Unknown4.04.53.64.46.1
BI-RADS category at first mammogram
    Entirely fat (1)9.311.29.213.810.6<0.0001
    Scattered fibroglandular (2)43.847.647.250.151.0
    Heterogeneously dense (3)39.535.538.031.933.1
    Extremely dense (4)7.45.75.64.25.3
BI-RADS category at second mammogram
    Entirely fat (1)7.69.57.410.711.4<0.0001
    Scattered fibroglandular (2)43.146.948.949.646.4
    Heterogeneously dense (3)42.538.439.535.637.5
    Extremely dense (4)6.85.24.24.14.7
HRT use
    Nonuser26.623.123.321.219.6<0.0001
    Initiator1.92.31.52.11.5
    Discontinuer31.030.832.431.230.8
    Continuer40.343.642.645.047.5
    Unknown0.20.20.20.50.6
Days between exams
    Mean634.9632.3639.1613.3619.3<0.0001
    SD130.5125.7128.5137.8135.7
    Median676670674661671
Age at menarche (y)
    Never0.30.40.40.70.5<0.0001
    <115.66.17.08.96.4
    11-1472.273.570.073.477.2
    ≥1510.510.812.09.28.0
    Unknown11.49.210.67.87.9
Family history
    No family history58.760.757.555.557.40.0004
    First-degree relative17.817.719.922.119.9
    Second-degree relative14.314.113.812.813.8
    Unknown9.27.58.89.68.9
Age at first birth (y)
    Not parous15.113.113.410.912.8<0.0001
    ≤1916.620.119.821.721.8
    20-2437.737.839.439.341.7
    25-2919.118.217.618.416.7
    ≥309.59.07.57.05.5
    Unknown2.01.82.32.71.5
  • * P values calculated from χ2 tests of independence between NSAID use category and each calculated for categorical characteristics and from ANOVA for continuous variables.