Table 4.
Differences in mammographic density measures by quartiles of plasma prolactin immunoassay and bioassay levels (ng/mL) among 234 postmenopausal women in the NHS and NHSII
| Prolactin Immunoassay (ng/ml) (N=234) |
Prolactin Bioassay (ng/ml) (N=234) |
|||||||||
|---|---|---|---|---|---|---|---|---|---|---|
| Q1 <7.0 (N=60) |
Q2 7.0–9.1 (N=57) |
Q3 9.1–12.5 (N=57) |
Q4 12.5+ (N=60) |
p- trend |
Q1 <4.8 (N=59) |
Q2 4.8–6.6 (N=58) |
Q3 6.6–9.6 (N=59) |
Q4 9.6+ (N=58) |
p-trend | |
| Percent density (%) | Percent density (%) | |||||||||
| Model 1a | Ref | 4.45 (−2.53,11.43) |
4.41 (−2.57,11.38) |
2.21 (−5.16,9.59) |
0.73 | Ref | 0.23 (−6.67,7.14) |
6.22 (−0.78,13.23) |
8.92 (1.80,16.05) |
<.0001 |
| Model 2b | Ref | 5.07 (−1.05,11.20) |
1.45 (−4.74,7.64) |
1.07 (−5.35,7.48) |
0.89 | Ref | −1.35 (−7.68,4.98) |
3.60 (−2.73,9.94) |
4.80 (−1.81,11.42) |
0.06 |
| Square-root dense area (cm2) | Square-root dense area (cm2) | |||||||||
| Model 1a | Ref | 0.37 (−0.53,1.26) |
0.14 (−0.76,1.03) |
0.47 (−0.47,1.42) |
0.42 | Ref | 0.01 (−0.87,0.90) |
0.21 (−0.68,1.10) |
1.07 (0.16,1.98) |
0.01 |
| Model 2b | Ref | 0.40 (−0.47,1.26) |
−0.09 (−0.96,0.78) |
0.30 (−0.60,1.20) |
0.70 | Ref | 0.02 (−0.84,0.87) |
−0.22 (−1.09,0.64) |
0.42 (−0.49,1.33) |
0.38 |
| Square-root non-dense area (cm2) | Square-root non-dense area (cm2) | |||||||||
| Model 1a | Ref | −0.15 (−1.26,0.95) |
−0.77 (−1.87,0.34) |
0.06 (−1.11,1.22) |
0.96 | Ref | 0.36 (−0.72,1.44) |
−1.09 (−2.17,0.00) |
−1.44 (−2.55,−0.34) |
<.0001 |
| Model 2b | Ref | 0.04 (−0.79,0.86) |
−0.15 (−0.99,0.68) |
0.14 (−0.73,1.00) |
0.79 | Ref | 0.50 (−0.29,1.30) |
−0.90 (−1.69,−0.11) |
−0.74 (−1.58,0.10) |
0.01 |
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).
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), smoking status (never, past, current), BMI (continuous),and past PMH use