Postmenopausal breast cancer risk in relation to sex steroid hormones, prolactin and SHBG (Sweden).
OBJECTIVE
High levels of sex steroid hormones and prolactin have been suggested to enhance breast cancer development. Low levels of SHBG may indicate high levels of (bio-available) steroid hormones. The present study investigates whether high levels of sex steroid hormones and prolactin, and/or low levels of SHBG, are associated with high breast cancer risk.


METHODS
Blood samples were collected in about 65,000 women participating in two population-based prospective cohort studies in Sweden. Follow-up yielded 173 postmenopausal breast cancer cases who had not been exposed to HRT. Levels of estrone, estradiol, SHBG, FSH, prolactin, testosterone, androstenedione and DHEAs were analysed in cases and 438 controls. Logistic regression analysis yielded odds ratios (ORs), with 95% confidence intervals, adjusted for potential confounders.


RESULTS
The risk of breast cancer was associated with the highest versus lowest quartiles of estrone, OR: 2.58 (1.50-4.44), estradiol (dichotomised: high versus low) (1.73: 1.04-2.88), and testosterone (1.87: 1.08-3.25). High risks, although not statistically significant, were seen for androstenedione (1.58: 0.92-2.72) and DHEAs (1.62: 0.89-2.72). No strong associations were seen between SHBG or prolactin and risk of breast cancer.


CONCLUSIONS
High levels of estrone, estradiol, testosterone, and possibly androstenedione and DHEAs, in postmenopausal women are associated with a high risk of subsequent breast cancer.
Manjer
Jonas
J
Department of Community Medicine, Malmö University Hospital, Lund University, Malmö, Sweden. jonas.manjer@smi.mas.lu.se
Johansson
Robert
R
Berglund
Göran
G
Janzon
Lars
L
Kaaks
Rudolf
R
Agren
Asa
A
Lenner
Per
P
D000735:Androstenedione / Q000097:blood; D001943:Breast Neoplasms / Q000097:blood* / Q000453:epidemiology; D016022:Case-Control Studies; D003687:Dehydroepiandrosterone / Q000097:blood; D004958:Estradiol / Q000097:blood; D004970:Estrone / Q000097:blood; D005260:Female; D012739:Gonadal Steroid Hormones / Q000097:blood*; D006801:Humans; D016015:Logistic Models; D008875:Middle Aged; D011388:Prolactin / Q000097:blood; D011446:Prospective Studies; D012307:Risk Factors; D012738:Sex Hormone-Binding Globulin / Q000378:metabolism; D013548:Sweden / Q000453:epidemiology; D013739:Testosterone / Q000097:blood
D012739:Gonadal Steroid Hormones; D012738:Sex Hormone-Binding Globulin; D004970:Estrone; D013739:Testosterone; D000735:Androstenedione; D003687:Dehydroepiandrosterone; D004958:Estradiol; D011388:Prolactin