Immunoassay and Nb2 lymphoma bioassay prolactin levels and mammographic density in premenopausal and postmenopausal women the Nurses’ Health Studies

Abstract

Background Higher circulating prolactin levels have been associated with higher percent mammographic density among postmenopausal women in some, but not all studies. However, few studies have examined associations with dense area and non-dense breast area breast or considered associations with prolactin Nb2 lymphoma cell bioassay levels. Methods We conducted a cross-sectional study among 1124 premenopausal and 890 postmenopausal women who were controls in breast cancer case-control studies nested in the Nurses’ Health Study (NHS) and NHSII. Participants provided blood samples in 1989–1990 (NHS) or 1996–1999 (NHSII) and mammograms were obtained from around the time of blood draw. Multivariable linear models were used to assess the associations between prolactin levels (measured by immunoassay or bioassay) with percent density, dense area, and non-dense area. Results Among 1124 premenopausal women, percent density, dense area, and non-dense area were not associated with prolactin immunoassay levels in multivariable models (p-trends=0.10, 0.18, and 0.69, respectively). Among 890 postmenopausal women, those with prolactin immunoassay levels in the highest versus lowest quartile had modestly, though significantly, higher percent density (difference=3.01 percentage points, 95%CI: 0.22, 5.80) as well as lower non-dense area (p-trend=0.02). Among women with both immunoassay and bioassay levels, there were no consistent differences in the associations with percent density between bioassay and immunoassay levels. Conclusions Postmenopausal women with prolactin immunoassay levels in the highest quartile had significantly higher percent density as well as lower non-dense area compared to those in the lowest quartile. Impact Future studies should examine the underlying biologic mechanisms, particularly for non-dense area.

Early-Life and Adult Anthropometrics in Relation to Mammographic Image Intensity Variation in the Nurses' Health Studies

“…Details of mammographic density measurement were described elsewhere (33). Briefly, a Lumysis 85 laser film scanner was used to digitize the craniocaudal views of both breasts for all mammograms in the NHS and for the first two batches of mammograms in the NHSII.…”

A comprehensive evaluation of interaction between genetic variants and use of menopausal hormone therapy on mammographic density

“…In humans, prolactin is primarily produced in the anterior pituitary gland, but it is also expressed in the mammary gland itself and adipose tissue, among others [ 49 ]. In postmenopausal women, higher prolactin levels have been associated with higher mammographic density in three studies [ 50 – 52 ], two other studies found no association [ 53 , 54 ].…”

Residential particulate matter and distance to roadways in relation to mammographic density: results from the Nurses’ Health Studies

“…Despite these high within-person intraclass correlation coefficients, between-batch variability was present in the NHSII. Batch adjustment methods were applied to the second and third NHSII batch measurements to reflect the density measurements had they been evaluated in the first batch [ 26 , 29 ]. The primary outcome of interest was percent mammographic density (i.e., the dense area divided by the total breast area), and secondary outcomes of interest included absolute dense area (cm 2 ) and absolute nondense area (cm 2 ).…”