Table 5.
Risk of breast cancer in relation to the combined effect of prolactin levels and mammographic density
| Percentage mammographic density (%), tertiles |
||||||
|---|---|---|---|---|---|---|
| First |
Second |
Third |
||||
| Category | No. of cases/controls | OR (95% CI) | No. of cases/controls | OR (95% CI) | No. of cases/controls | OR (95% CI) |
| Premenopausal women*,† | ||||||
| Prolactin first tertile | 13/40 | 1.0 | 26/47 | 1.90 (0.78 to 4.67) | 30/49 | 2.71 (1.06 to 6.50) |
| Prolactin second tertile | 16/52 | 1.04 (0.41 to 2.65) | 22/48 | 1.37 (0.53 to 3.53) | 33/36 | 3.60 (1.44 to 9.00) |
| Prolactin third tertile | 20/44 | 1.77 (0.73 to 4.34) | 30/42 | 2.69 (1.11 to 6.54) | 41/49 | 3.15 (1.29 to 7.65) |
| Pinteraction = .44‖ | ||||||
| Postmenopausal women‡,§ | ||||||
| Prolactin first tertile | 41/111 | 1.0 | 65/112 | 2.06 (1.24 to 3.35) | 54/103 | 1.86 (1.07 to 3.25) |
| Prolactin second tertile | 42/110 | 1.09 (0.64 to 1.86) | 59/103 | 1.78 (1.06 to 3.01) | 73/109 | 2.44 (1.42 to 4.17) |
| Prolactin third tertile | 28/105 | 0.65 (0.36 to 1.19) | 44/107 | 1.49 (0.87 to 2.57) | 76/113 | 2.44 (1.44 to 4.14) |
| Pinteraction = .11‖ | ||||||
Mammographic density: Q1: <18.87%, Q2: 18.88–40.43, Q3: >40.44. Prolactin: Q1: <11.49 ng/mL, Q2: 11.50–19.46, Q3: >19.47. BMI = body-mass index; CI = confidence interval; OR = odds ratio.
Adjusted for age and BMI at blood draw, benign breast disorder (no, yes), breast cancer in family (no, yes), smoking status (never, previous, or current smoker), age at menarche, and number of births (0, 1, 2, or ≥3).
Mammographic density: Q1: <4.55%, Q2: 4.56–15.58, Q3: >15.59. Prolactin: Q1: <8.65%, Q2: 8.66–13.46, Q3: >13.47.
Adjusted for age and BMI at blood draw, benign breast disorder (no, yes), breast cancer in family (no, yes), smoking status (never, previous, or current smoker), age at menarche, number of births (0, 1, 2, or ≥3), and ever use of hormone replacement therapy.
On the basis of a two-sided log-likelihood ratio test.