Table 3.
Differences in mammographic density measures by quartiles of plasma prolactin immunoassay and bioassay levels (ng/mL) among 317 premenopausal women in the NHS and NHSII
| Prolactin Immunoassay (ng/ml) (N=317) |
Prolactin Bioassay (ng/ml) (N=317) |
|||||||||
|---|---|---|---|---|---|---|---|---|---|---|
| Q1 <9.2 (N=79) |
Q2 9.2–13.0 (N=79) |
Q3 13.0–17.4 (N=79) |
Q4 >17.4 (N=80) |
p-trend | Q1 <6.4 (N=80) |
Q2 6.4–8.8 (N=79) |
Q3 8.8–11.9 (N=78) |
Q4 >11.9 (N=80) |
p-trend | |
| Percent density (%) | Percent density (%) | |||||||||
| Model 1a | Ref | 1.23 (−5.33,7.78) |
5.38 (−1.22,11.98) |
3.32 (−3.57,10.22) |
0.28 | Ref | 2.85 (−3.68,9.39) |
6.79 (0.28,13.30) |
5.04 (−1.70,11.78) |
0.10 |
| Model 2b | Ref | 3.23 (−2.63,9.10) |
4.60 (−1.37,10.57) |
6.51 (0.19,12.82) |
0.05 | Ref | 3.06 (−2.80,8.92) |
3.94 (−1.95,9.83) |
3.85 (−2.23,9.93) |
0.22 |
| Square-root dense area (cm2) | Square-root dense area (cm2) | |||||||||
| Model 1a | Ref | 0.63 (−0.19,1.45) |
0.56 (−0.27,1.39) |
0.69 (−0.17,1.55) |
0.18 | Ref | −0.09 (−0.90,0.73) |
0.65 (−0.17,1.46) |
0.34 (−0.51,1.18) |
0.25 |
| Model 2b | Ref | 0.64 (−0.15,1.44) |
0.23 (−0.59,1.04) |
0.90 (0.04,1.75) |
0.09 | Ref | −0.14 (−0.95,0.68) |
0.43 (−0.39,1.25) |
0.34 (−0.51,1.19) |
0.28 |
| Square-root non-dense area (cm2) | Square-root non-dense area (cm2) | |||||||||
| Model 1a | Ref | 0.26 (−0.78,1.31) |
−0.76 (−1.80,0.29) |
0.20 (−0.90,1.29) |
0.98 | Ref | −0.59 (−1.64,0.45) |
−0.91 (−1.95,0.13) |
−0.46 (−1.54,0.62) |
0.39 |
| Model 2b | Ref | −0.03 (−0.85,0.80) |
−0.67 (−1.51,0.17) |
−0.10 (−1.00,0.79) |
0.64 | Ref | −0.76 (−1.60,0.08) |
−0.46 (−1.30,0.38) |
−0.23 (−1.10,0.64) |
0.81 |
Model 1: age at mammography (continuous), month of blood draw (continuous), fasting status (<8 hours or unknown, ≥8 hours since last meal), time of day (12am–5:59am, 6:00am–7:59am, 8:00am–11:59pm), and cohort.
Includes covariates in Model 1 and history of bbd (yes/no), family history of breast cancer (yes/no), age at menarche (<12, 12, 13, 14+), parity and age at first birth (nulliparous, 1–2 children age at first birth <25y, 1–2 children age at first birth 25–29y, 1–2 children age at first birth ≥30 y, 3+ children age at first birth <25y, 3+ children age at first birth 25+y), breastfeeding (<1 month, 1–18 months, 18+ months), alcohol consumption (0, <5, 5–<15, ≥15g/d, missing), and smoking status (never, past, current)
Includes covariates in Model 2 and BMI (continuous)