Table 3.
Associationa Between Exogenous Hormone Use and Postmenopausal Breast Cancer Risk by Histological Type in the NIH-AARP Diet and Health Study Cohort, 1995–2006
| Person-Years | Histological Type |
P for Heterogeneityb | |||||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Ductal |
Mucinous |
Tubular |
Lobular |
Mixed Ductal-Lobular |
|||||||||||||
| No. of Cases | HR | 95% CI | No. of Cases | HR | 95% CI | No. of Cases | HR | 95% CI | No. of Cases | HR | 95% CI | No. of Cases | HR | 95% CI | |||
| Any MHT | |||||||||||||||||
| Never use | 846,195 | 2,213 | 1 | Reference | 91 | 1 | Reference | 30 | 1 | Reference | 350 | 1 | Reference | 243 | 1 | Reference | <0.01 |
| Former use | 171,131 | 445 | 1.08 | 0.97, 1.21 | 20 | 1.05 | 0.62, 1.80 | 7 | 1.31 | 0.54, 3.19 | 59 | 0.91 | 0.68, 1.23 | 35 | 0.82 | 0.56, 1.20 | |
| Current use | 821,582 | 2,667 | 1.39 | 1.30, 1.49 | 105 | 1.40 | 0.99, 1.97 | 95 | 4.39 | 2.77, 6.96 | 426 | 1.45 | 1.22, 1.72 | 357 | 1.75 | 1.44, 2.13 | |
| Years of MHT use | |||||||||||||||||
| Never use | 846,195 | 2,139 | 1 | Reference | 91 | 1 | Reference | 30 | 1 | Reference | 344 | 1 | Reference | 231 | 1 | Reference | 0.02 |
| <5 | 353,116 | 1,007 | 1.19 | 1.10, 1.30 | 36 | 1.14 | 0.74, 1.77 | 28 | 2.52 | 1.44, 4.40 | 150 | 1.17 | 0.94, 1.44 | 120 | 1.29 | 1.01, 1.64 | |
| 5–9 | 250,532 | 848 | 1.38 | 1.26, 1.52 | 25 | 1.16 | 0.70, 1.93 | 36 | 4.48 | 2.62, 7.66 | 135 | 1.47 | 1.18, 1.84 | 113 | 1.69 | 1.32, 2.18 | |
| ≥10 | 391,198 | 1,260 | 1.46 | 1.34, 1.59 | 64 | 1.58 | 1.07, 2.35 | 38 | 4.84 | 2.82, 8.30 | 200 | 1.43 | 1.15, 1.77 | 161 | 1.83 | 1.44, 2.33 | |
| P-trend | <0.01 | 0.03 | <0.01 | <0.01 | <0.01 | ||||||||||||
| Estrogen-only MHTc | |||||||||||||||||
| Never use | 429,280 | 1,156 | 1 | Reference | 48 | 1 | Reference | 19 | 1 | Reference | 181 | 1 | Reference | 117 | 1 | Reference | 0.27 |
| Former use | 87,972 | 210 | 0.97 | 0.82, 1.13 | 12 | 0.98 | 0.48, 2.00 | 1 | 36 | 1.14 | 0.78, 1.68 | 19 | 0.98 | 0.59, 1.63 | |||
| Current use | 228,010 | 597 | 1.15 | 1.01, 1.29 | 34 | 1.30 | 0.76, 2.21 | 11 | 2.50 | 1.04, 6.02 | 114 | 1.51 | 1.12, 2.03 | 77 | 1.60 | 1.13, 2.28 | |
| Combination (estrogen plus progestin) MHTc | |||||||||||||||||
| Never use | 429,280 | 1,156 | 1 | Reference | 48 | 1 | Reference | 19 | 1 | Reference | 181 | 1 | Reference | 117 | 1 | Reference | 0.02 |
| Former use | 119,810 | 377 | 1.23 | 1.08, 1.40 | 22 | 1.84 | 1.06, 3.21 | 8 | 1.10 | 0.40, 3.04 | 57 | 1.24 | 0.90, 1.70 | 43 | 1.39 | 0.96, 2.02 | |
| Current use | 187,165 | 844 | 1.74 | 1.58, 1.93 | 18 | 1.21 | 0.66, 2.21 | 48 | 4.97 | 2.74, 9.01 | 130 | 1.66 | 1.29, 2.14 | 129 | 2.50 | 1.89, 3.30 | |
| Oral contraceptives | |||||||||||||||||
| Never use | 1,117,014 | 3,216 | 1 | Reference | 163 | 1 | Reference | 71 | 1 | Reference | 505 | 1 | Reference | 379 | 1 | Reference | 0.10 |
| Ever use | 710,050 | 2,071 | 1.06 | 0.99, 1.13 | 52 | 0.67 | 0.47, 0.95 | 61 | 1.33 | 0.91, 1.94 | 325 | 1.10 | 0.94, 1.30 | 254 | 1.09 | 0.91, 1.31 | |
| Years of oral contraceptive use | |||||||||||||||||
| Never use | 1,117,014 | 3,216 | 1 | Reference | 163 | 1 | Reference | 71 | 1 | Reference | 505 | 1 | Reference | 379 | 1 | Reference | 0.09 |
| 1–4 | 315,458 | 904 | 1.04 | 0.96, 1.13 | 31 | 0.91 | 0.59, 1.38 | 26 | 1.38 | 0.85, 2.24 | 130 | 1.00 | 0.81, 1.24 | 119 | 1.18 | 0.94, 1.49 | |
| 5–9 | 222,214 | 650 | 1.08 | 0.98, 1.18 | 15 | 0.64 | 0.36, 1.12 | 15 | 1.07 | 0.60, 1.92 | 100 | 1.05 | 0.82, 1.34 | 77 | 1.05 | 0.81, 1.38 | |
| ≥10 | 172,378 | 517 | 1.07 | 0.97, 1.18 | 6 | 0.28 | 0.11, 0.70 | 20 | 1.53 | 0.90, 2.60 | 95 | 1.35 | 1.06, 1.71 | 58 | 0.98 | 0.73, 1.32 | |
| P-trend | 0.08 | <0.01 | 0.17 | 0.04 | 0.86 | ||||||||||||
Abbreviations: CI, confidence interval; HR, hazard ratio; MHT, menopausal hormone therapy; NIH, National Institutes of Health.
a Estimates were adjusted for age at baseline, education, race, marital status, age at menarche, parity/age at first birth, type of and age at menopause, alcohol use, body mass index, frequency of vigorous physical activity, number of previous breast biopsies, family history of breast cancer (first-degree relative), and all other variables in the table, except where noted. Associations are not shown for comparisons involving fewer than 5 cases.
b Two-sided P value from the Wald test, simultaneously comparing associations for ductal, mucinous, tubular, lobular, and mixed ductal-lobular types.
c Assessed only among women who completed the second study questionnaire.