Body mass index, circulating levels of sex-steroid hormones, IGF-I and IGF-binding protein-3: a cross-sectional study in healthy women.
OBJECTIVE
Excess weight has been associated with increased risk of cancer at several organ sites. In part, this effect may be modulated through alterations in the metabolism of sex steroids and IGF-I related peptides. The objectives of the study were to examine the association of body mass index (BMI) with circulating androgens (testosterone, androstenedione and dehydroepiandrosterone sulfate (DHEAS)), estrogens (estrone and estradiol), sex hormone-binding globulin (SHBG), IGF-I and IGF-binding protein (IGFBP)-3, and the relationship between sex steroids, IGF-I and IGFBP-3.


METHODS
A cross-sectional analysis was performed using hormonal and questionnaire data of 620 healthy women (177 pre- and 443 post-menopausal). The laboratory measurements of the hormones of interest were available from two previous case-control studies on endogenous hormones and cancer risk.


RESULTS
In the pre-menopausal group, BMI was not related to androgens and IGF-I. In the post-menopausal group, estrogens, testosterone and androstenedione increased with increasing BMI. The association with IGF-I was non-linear, with the highest mean concentrations observed in women with BMI between 24 and 25. In both pre- and post-menopausal subjects, IGFBP-3 did not vary across BMI categories and SHBG decreased with increasing BMI. As for the correlations between peptide and steroid hormones, in the post-menopausal group, IGF-I was positively related to androgens, inversely correlated with SHBG, and not correlated with estrogens. In the pre-menopausal group, similar but weaker correlations between IGF-I and androgens were observed.


CONCLUSIONS
These observations offer evidence that obesity may influence the levels of endogenous sex-steroid and IGF-related hormones in the circulation, especially after menopause. Circulating IGF-I, androgens and SHBG appear to be related to each other in post-menopausal women.
Lukanova
A
A
Hormones and Cancer Group, International Agency for Research on Cancer, Lyon, France. lukanova@iarc.fr
Lundin
E
E
Zeleniuch-Jacquotte
A
A
Muti
P
P
Mure
A
A
Rinaldi
S
S
Dossus
L
L
Micheli
A
A
Arslan
A
A
Lenner
P
P
Shore
R E
RE
Krogh
V
V
Koenig
K L
KL
Riboli
E
E
Berrino
F
F
Hallmans
G
G
Stattin
P
P
Toniolo
P
P
Kaaks
R
R
D000328:Adult; D000368:Aged; D000728:Androgens / Q000097:blood*; D000735:Androstenedione / Q000097:blood; D015992:Body Mass Index; D016022:Case-Control Studies; D015331:Cohort Studies; D003430:Cross-Sectional Studies; D019314:Dehydroepiandrosterone Sulfate / Q000097:blood; D004958:Estradiol / Q000097:blood; D004967:Estrogens / Q000097:blood; D004970:Estrone / Q000097:blood; D005260:Female; D006801:Humans; D018972:Insulin-Like Growth Factor Binding Protein 3 / Q000097:blood*; D007334:Insulin-Like Growth Factor I / Q000032:analysis*; D008875:Middle Aged; D009765:Obesity / Q000503:physiopathology; D017698:Postmenopause / Q000097:blood*; D017697:Premenopause / Q000097:blood*; D012016:Reference Values; D012738:Sex Hormone-Binding Globulin / Q000032:analysis; D013739:Testosterone / Q000097:blood
D000728:Androgens; D004967:Estrogens; D018972:Insulin-Like Growth Factor Binding Protein 3; D012738:Sex Hormone-Binding Globulin; D004970:Estrone; D013739:Testosterone; D000735:Androstenedione; D004958:Estradiol; D019314:Dehydroepiandrosterone Sulfate; D007334:Insulin-Like Growth Factor I