The permanent effect of reproductive events on blood prolactin levels and its relation to breast cancer risk: a population study of postmenopausal women

Reproductive factors and family history of breast cancer in relation to plasma prolactin levels in premenopausal and postmenopausal women

“…9 In the other 2 studies, the change in prolactin levels with each child was relatively small (<1 ng/mL), similar to what we observed with a continuous variable, and may have been statistically significant given the large sample sizes (n 5 4,550 and 2,119). 12,14 While pregnancy appears to decrease prolactin levels, an additional benefit of earlier age at first birth has not been shown in the few prior studies of this association [11][12][13][14] or in the current study.…”

“…[11][12][13][14][15] Few studies have examined these associations in postmenopausal women. 9,14 A prior analysis of the correlations between breast cancer risk factors and prolactin levels was conducted among 217 postmenopausal women within the Nurses' Health Study (NHS). 16 The current analysis expands upon this preliminary assessment and examines the associations of reproductive factors, benign breast disease and family history of breast cancer with plasma prolactin levels in 1,089 premenopausal and 1,311 postmenopausal women in a cross-sectional study within the NHS and the NHSII.…”

“…Other birthrelated factors, such as age at first birth, time since last birth and history of lactation, have been assessed in only a few studies, with no clear associations. [11][12][13][14][15] Few studies have examined these associations in postmenopausal women. 9,14 A prior analysis of the correlations between breast cancer risk factors and prolactin levels was conducted among 217 postmenopausal women within the Nurses' Health Study (NHS).…”

“…7,8 While the association between prolactin levels and breast cancer risk is fairly consistent, whether lifestyle or reproductive factors influence prolactin levels is not well known. A number of cross-sectional studies have observed an inverse association between parity and prolactin levels in both premenopausal [9][10][11][12][13] and postmenopausal 9,14 women, although whether prolactin levels decline further after the first pregnancy is unclear. Other birthrelated factors, such as age at first birth, time since last birth and history of lactation, have been assessed in only a few studies, with no clear associations.…”

The association of breast mitogens with mammographic densities

“…Blood levels of growth hormone, IGF-I and prolactin also decline with increasing age (Hall et al, 1999). Prolactin levels are also permanently reduced by pregnancy, and are lower after the menopause than before (Reyes et al, 1977;Wang et al, 1988;Metka et al, 1995;Nasu et al, 1997).…”