Table 1 Breast cancer risk associated with estrogen-alone therapy (ET) in women with hysterectomy and estrogen plus progestin therapy (EPT) in women with intact uteri; restricted to postmenopausal women with follow-up MHT information in 2004 the National Institutes of Health-AARP Diet and Health Study cohort

Total

940

1539

MHT use

 Never

232

1.00 (referent)

436

1.00 (referent)

 Ever

708

0.90 (0.74–1.11)

1103

1.20 (1.06–1.37)

Ever MHT use

 BMI < 25

420

0.88 (0.62–1.24)

695

1.32 (1.09–1.61)

 BMI 25 < 30

284

1.10 (0.75–1.62)

479

1.10 (0.87–1.39)

 BMI ≥ 30.0

214

0.74 (0.51–1.07)

338

1.21 (0.91–1.62)

p_trend = 0.87

p_trend < 0.0001

Recency

 Former

596

0.77 (0.62–0.96)

1023

1.14 (0.99–1.30)

 Current

112

1.35 (1.04–1.75)

80

1.80 (1.39–2.32)

Duration, years

 < 5

20

0.77 (0.39–1.50)

164

0.83 (0.64–1.08)

 5–9

35

0.90 (0.55–1.48)

184

1.04 (0.81–1.32)

 10–14

85

1.05 (0.73–1.51)

296

1.37 (1.12–1.68)

 15–19

106

1.12 (0.80–1.56)

227

1.39 (1.11–1.75)

 ≥ 20

254

0.93 (0.72–1.21)

113

1.21 (0.86–1.72)

p_trend = 0.57

p_trend = 0.002

Time since last use, former users, years

 < 5

193

0.69 (0.47–1.02)

358

1.23 (0.96–1.58)

 5–9

80

0.82 (0.60–1.12)

189

1.18 (0.98–1.42)

 ≥ 10

78

0.80 (0.57–1.13)

92

1.18 (0.93–1.49)

p_trend < 0.0001

p_trend < 0.0001