Circulating levels of sex hormones and their relation to risk factors for breast cancer: a cross-sectional study in 1092 pre- and postmenopausal women (United Kingdom).
OBJECTIVE
To investigate the relationships between plasma concentrations of sex hormones and risk factors for breast cancer.


METHODS
We investigated the relationship of plasma concentrations of estradiol, progesterone, follicle-stimulating hormone (FSH), luteinizing hormone (LH) and sex hormone-binding globulin (SHBG) with breast cancer risk factors in 636 premenopausal and 456 postmenopausal women. Risk factor data were obtained from questionnaires and hormone concentrations measured by immunoassays; variations in geometric means were compared using analysis of covariance.


RESULTS
SHBG decreased with increasing body mass index and increasing waist-hip ratio both in pre- and postmenopausal women. In postmenopausal women only, estradiol increased with increasing body mass index. In premenopausal women, estradiol decreased with increasing physical activity, estradiol was higher in current than in ex- and non-smokers, and FSH decreased with increasing alcohol intake. No associations were observed between sex hormones and age at menarche, parity, age at menopause, and previous use of oral contraceptives in either pre- or postmenopausal women.


CONCLUSIONS
Certain factors such as obesity and perhaps waist-hip ratio, physical activity and alcohol consumption, but probably not age at menarche and parity, may mediate their effects on breast cancer risk by changing circulating concentrations of sex hormones.
Verkasalo
P K
PK
Imperial Cancer Research Fund Cancer Epidemiology Unit, University of Oxford, UK. p.verkasalo@icrf.icnet.uk
Thomas
H V
HV
Appleby
P N
PN
Davey
G K
GK
Key
T J
TJ
D000328:Adult; D000368:Aged; D000428:Alcohol Drinking / Q000009:adverse effects; D000704:Analysis of Variance; D001824:Body Constitution; D015992:Body Mass Index; D001943:Breast Neoplasms / Q000453:epidemiology / Q000209:etiology*; D003430:Cross-Sectional Studies; D004958:Estradiol / Q000097:blood*; D015444:Exercise; D005260:Female; D005640:Follicle Stimulating Hormone / Q000097:blood*; D012739:Gonadal Steroid Hormones / Q000097:blood*; D006801:Humans; D008019:Life Style; D007986:Luteinizing Hormone / Q000097:blood*; D008875:Middle Aged; D009765:Obesity / Q000150:complications / Q000175:diagnosis; D017698:Postmenopause / Q000097:blood*; D017697:Premenopause / Q000097:blood*; D011374:Progesterone / Q000097:blood*; D012307:Risk Factors; D012738:Sex Hormone-Binding Globulin / Q000378:metabolism*; D012907:Smoking / Q000009:adverse effects; D011795:Surveys and Questionnaires; D006113:United Kingdom / Q000453:epidemiology
D012739:Gonadal Steroid Hormones; D012738:Sex Hormone-Binding Globulin; D011374:Progesterone; D004958:Estradiol; D007986:Luteinizing Hormone; D005640:Follicle Stimulating Hormone