Table 5. Odds ratios for incident breast cancer in relation to tertiles of plasma sex hormone and SHBG level and percentage mammographic density, Breakthrough Generations Study, United Kingdom.
|
Percentage mammographic density (%), tertilesa |
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|---|---|---|---|---|---|---|
| |
1st |
2nd |
3rd |
|||
| Sex hormone or SHBG level (tertiles) | Cases/controls | ORb (95% CI) | Cases/controls | ORb (95% CI) | Cases/controls | ORb (95% CI) |
|
Oestradiolc | ||||||
| 1st | 11/31 | 1.00 | 25/34 | 2.60 (0.96–7.05) | 38/45 | 2.97 (1.16–7.60) |
| 2nd | 17/38 | 1.53 (0.54–4.37) | 28/33 | 4.18 (1.55–11.3) | 33/37 | 2.58 (0.98–6.80) |
| 3rd | 28/41 | 2.88 (1.04–8.02) | 35/44 | 3.68 (1.39–9.76) | 47/27 | 7.81 (2.89–21.1) |
| |
|
|
|
|
|
P interactiond=0.276 |
|
Free oestradiolc | ||||||
| 1st | 12/34 | 1.00 | 25/30 | 3.15 (1.18–8.36) | 44/46 | 3.34 (1.37–8.15) |
| 2nd | 15/38 | 1.21 (0.43–3.42) | 32/37 | 4.02 (1.57–10.3) | 28/34 | 2.53 (0.97–6.57) |
| 3rd | 29/38 | 3.17 (1.17–8.63) | 31/44 | 2.88 (1.11–7.74) | 46/29 | 6.23 (2.40–16.2) |
| |
|
|
|
|
|
P interactiond=0.116 |
|
Testosteronec | ||||||
| 1st | 10/36 | 1.00 | 31/35 | 3.91 (1.46–10.5) | 33/39 | 2.96 (1.10–7.95) |
| 2nd | 23/35 | 2.18 (0.80–5.95) | 26/44 | 2.61 (0.95–7.11) | 40/33 | 4.60 (1.75–12.1) |
| 3rd | 23/40 | 2.18 (0.79–5.99) | 31/32 | 4.23 (1.59–11.3) | 45/39 | 4.57 (1.75–11.9) |
| |
|
|
|
|
|
P interactiond=0.434 |
|
Free testosteronec | ||||||
| 1st | 12/36 | 1.00 | 28/35 | 3.33 (1.28–8.67) | 34/39 | 2.85 (1.11–7.31) |
| 2nd | 15/34 | 1.65 (0.59–4.62) | 22/39 | 2.74 (1.02–7.35) | 37/39 | 3.44 (1.38–8.57) |
| 3rd | 29/41 | 2.35 (0.91–6.07) | 38/37 | 3.60 (1.45–8.93) | 47/33 | 5.00 (2.00–12.55) |
| |
|
|
|
|
|
P interactiond=0.768 |
|
SHBGc | ||||||
| 1st | 31/46 | 1.00 | 31/42 | 1.20 (0.55–2.63) | 30/21 | 2.23 (0.92–5.42) |
| 2nd | 16/33 | 0.62 (0.25–1.57) | 36/36 | 1.68 (0.75–3.76) | 45/41 | 1.52 (0.68–3.38) |
| 3rd | 9/32 | 0.35 (0.13–0.97) | 21/33 | 1.08 (0.43–2.71) | 43/49 | 1.20 (0.53–2.73) |
| P interactiond=0.517 | ||||||
Abbreviations: CI=confidence interval; OR=odds ratio; SHBG=sex hormone-binding globulin.
Tertiles: <9.99, 9.99–24.09, >24.09%.
Covariates: year of entry to the study (⩽2005, 2006, 2007, ⩾2008); age at entry (5-year age groups); blood in post (0–1, 2, ⩾3 days, not known); years breast cancer free in study (0–6); body mass index, kg m−2 (continuous); parity (nulliparous; age at first birth <25 years/1–2 children; age at first birth <25 years/⩾3 children; age at first birth 25–29 years/1–2 children; age at first birth 25–29 years/⩾3 children; age at first birth ⩾30 years/1–4 children); family history of breast cancer (yes, no); age at menarche (⩽12, 13, 14, 15–20, not known); age at menopause (<45, 45–49, 50–54, ⩾55, not known); years of postmenopausal hormone therapy use (never, <2, 2–5, 6–9, ⩾10, not known); alcohol units (0, <5, 5–14, ⩾15 g per day, not known); laboratory batch.
1st, 2nd, 3rd tertile, respectively, oestradiol: <14.77, 14.77–24.45, >24.45 pmol l−1; free oestradiol: <0.35, 0.35–0.61, >0.61 pmol l−1; testosterone: <0.49, 0.49–0.84, >0.84 nmol l−1; free testosterone: <0.0064, 0.0064–0.0115, >0.0115 nmol l−1; SHBG: <35.2, 35.2–52.7, >52.7 nmol l−1.
On the basis of log-likelihood ratio test.