Table 1 Baseline characteristics of the analytic cohort
Premenopausal | Postmenopausal, current HT use | Postmenopausal, not using HT | ||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|
(N = 46,822) | (N = 36,977) | (N = 21,788) | ||||||||||
Number | % | Median | IQR | Number | % | Median | IQR | Number | % | Median | IQR | |
Age (years) | 41 | 34–46 | 57 | 52–65 | 64 | 55–72 | ||||||
Age at menarche (years) | 12 | 12–13 | 12 | 12–13 | 13 | 12–13 | ||||||
Parous | 30,580 | 65.3% | 28,793 | 77.9% | 16,440 | 75.5% | ||||||
Age at first full-term pregnancy (among parous) | 28 | 25–30 | 25 | 22–28 | 25 | 23–29 | ||||||
History of benign breast biopsy | 4491 | 9.6% | 7726 | 20.9% | 3776 | 17.3% | ||||||
Mother or sister with breast cancer | 4482 | 9.6% | 4503 | 12.2% | 3241 | 14.9% | ||||||
Consumption of a plant-based diet (factor score) | -0.35 | -0.86 -0.33 | -0.07 | -0.65 -0.65 | 0.01 | -0.60 -0.76 | ||||||
Alcohol consumption (g/day) | ||||||||||||
none | 15,215 | 32.5% | 10,463 | 28.3% | 7810 | 35.8% | ||||||
<20 | 26,397 | 56.4% | 21,315 | 57.6% | 10,803 | 49.6% | ||||||
≥20 | 2692 | 5.7% | 3575 | 9.7% | 1918 | 8.8% | ||||||
Socioeconomic status (deciles) | ||||||||||||
1–2 (low) | 1820 | 3.9% | 1053 | 2.8% | 968 | 4.4% | ||||||
3–4 | 5858 | 12.5% | 3676 | 9.9% | 2833 | 13.0% | ||||||
5–6 | 8656 | 18.5% | 5552 | 15.0% | 3683 | 16.9% | ||||||
7–8 | 14,884 | 31.8% | 10,673 | 28.9% | 6224 | 28.6% | ||||||
9–10 (high) | 15,041 | 32.1% | 15,559 | 42.1% | 7777 | 35.7% | ||||||