Introduction
Materials and methods
Never HT (n = 14,070) | Past HT (n = 7914) | Current E (n = 15,407) | Current EP (n = 16,934) | |
---|---|---|---|---|
Mean age in years | 66.5 | 68.2 | 63.3 | 58.9 |
% Non-Hispanic white | 85.3 | 87.9 | 90.1 | 92.2 |
% First-degree family history of breast cancer | 15.2 | 14.9 | 13.2 | 12.2 |
% BMI overweight or obese ≥25 kg/m2 | 45.2 | 45.2 | 41.6 | 34.9 |
% High alcohol intake (average ≥20 g/day) | 8.6 | 9.3 | 9.5 | 10.4 |
% Highest quartile of residential socioeconomic status | 44.4 | 44.8 | 47.5 | 52.5 |
% Menarche at age 11 years or younger | 22.0 | 23.4 | 23.6 | 20.9 |
% Nulliparous | 23.5 | 19.5 | 18.8 | 19.5 |
% Parous before age 35 years | 70.2 | 74.8 | 76.3 | 75.1 |
Results
Baseline characteristics according to HT use history
Breast cancer incidence rates
Period | Woman |
In situ
| Invasive | ER positive | ER negative | ||||
---|---|---|---|---|---|---|---|---|---|
years | n | AAIR (95% CI) | n | AAIR (95% CI) | n | AAIR (95% CI) | n | AAIR (95% CI) | |
1996-99 | 208,860 | 207 | 95.2 (81.6-108.7) | 1072 | 501.7 (470.3-533.1) | 765 | 358.7 (332.1-385.3) | 127 | 59.5 (48.6-70.3) |
2000-02 | 158,917 | 197 | 113.7 (96.5-130.9) | 914 | 528.0 (491.1-564.9) | 676 | 390.6 (358.8-422.3) | 103 | 59.4 (46.9-71.9) |
2003-05 | 149,509 | 161 | 98.2 (79.1-117.3) | 682 | 390.6 (355.6-425.7) | 504 | 293.8 (261.9-325.7) | 94 | 51.0 (40.5-61.5) |
Total cases | 565 | 2668 | 1945 | 324 | |||||
% change 1996-99 to 2000-02 | 19.4% P = 0.09 | 5.2% P = 0.30 | 8.9% P = 0.13 | -0.2% P = 0.99 | |||||
% change 2000-02 to 2003-05 | -13.6% P = 0.24 | -26.0% P < 0.001 | -24.8% P < 0.001 | -14.1% P = 0.38 |
Incidence rates by HT use history
Period | Never HT | Past HT | Current E | Current EP |
---|---|---|---|---|
AAIR (95% CI) | AAIR (95% CI) | AAIR (95% CI) | AAIR (95% CI) | |
Invasive breast cancer | ||||
1996-99 | 399.0 (341.7-456.3) | 343.7 (268.8-418.6) | 567.5 (501.1-633.9) | 680.8 (576.7-784.8) |
2000-02 | 334.7 (278.5-390.9) | 410.6 (300.7-520.6) | 509.6 (438.9-580.2) | 782.7 (687.1-878.2) |
2003-05 | 374.1 (308.1-440.1) | 297.8 (218.5-377.2) | 376.4 (314.7-438.1) | 424.6 (353.5-495.7) |
% change 1996-99 to 2000-02 | -16.1% P = 0.13 | 19.5% P = 0.31 | -10.2% P = 0.11 | 15.0% P = 0.016 |
% change 2000-02 to 2003-05 | 11.8% P = 0.38 | -27.5% P = 0.17 | -26.1% P = 0.010 | -45.8% P < 0.001 |
In Situ breast cancer | ||||
1996-99 | 65.0 (41.1-88.9) | 87.5 (43.2-131.7) | 85.4 (60.2-110.6) | 187.0 (128.3-245.6) |
2000-02 | 64.5 (39.5-89.6) | 96.6 (29.7-163.5) | 107.5 (78.1-136.9) | 169.2 (128.6-209.9) |
2003-05 | 103.1 (60.5-145.7) | 131.7 (163.5-160.6) | 82.4 (56.5-108.3) | 90.1 (65.4-114.8) |
% change 1996-99 to 2000-02 | -0.8% P = 0.98 | 10.4% P = 0.82 | 25.9% P = 0.12 | -9.5% P = 0.38 |
% change 2000-02 to 2003-05 | 59.8% P = 0.10 | 36.3% P = 0.51 | -23.3% P = 0.23 | -46.7% P = 0.008 |
Period | Never HT | Past HT | Current E | Current EP |
---|---|---|---|---|
AAIR (95% CI) | AAIR (95% CI) | AAIR (95% CI) | AAIR (95% CI) | |
Invasive breast cancer | ||||
2001-02 | 369.3 (285.6-452.9) | 561.1 (432.4-689.8) | 534.9 (424.7-645.1) | 665.8 (565.9-765.7) |
2003-05 | 343.7 (272.8-414.5) | 340.0 (265.6-414.4) | 406.4 (324.7-488.0) | 461.9 (392.5-531.4) |
% change | -6.9% P = 0.33 | -39.4% P = 0.003 | -24.0% P = 0.030 | -30.6% P = 0.001 |
In Situ breast cancer | ||||
2001-02 | 86.6 (44.0-129.1) | 100.5 (32.4-168.6) | 137.7 (83.2-192.3) | 135.0 (95.2-174.9) |
2003-05 | 107.2 (63.1-151.3) | 99.5 (60.3-138.8) | 123.6 (67.3-179.9) | 115.5 (78.1-152.8) |
% change | 23.8% P = 0.26 | -1.0% P = 0.49 | -10.2% P = 0.35 | -14.4% P = 0.22 |