The relationship between obesity and race on inhibin B during the menopause transition.
OBJECTIVE
Data are lacking on the effects of obesity and race on inhibin B levels during the menopause transition. The purpose of this study was to determine the relationship among inhibin B levels, body mass index (BMI), and race during the menopause transition.


METHODS
In the Penn Ovarian Aging Study, a prospective cohort study of reproductive aging, 436 women aged 35 to 47 years were followed up with serial hormones, anthropometric measures, and questionnaires for 6 years. Univariate and multivariable analyses were performed comparing mean log transformed inhibin B levels among menopause stages, age groups, BMI categories, races, and smoking groups.


RESULTS
In the univariate analyses, mean inhibin B levels were negatively associated with menopause stage, age, and BMI, but not significantly with race or smoking. Interactions of menopause status and BMI were significant (P < 0.001). Premenopausal women with a BMI of 25 or higher had significantly lower inhibin B levels compared with women with a BMI of less than 25 (41.8 pg/mL vs 58.4 pg/mL, P < 0.001), whereas postmenopausal women with a BMI of 30 or higher had significantly higher inhibin B levels compared with the postmenopausal women with a BMI of less than 25 (29.1 pg/mL vs 26.7 pg/mL, P < 0.001).


CONCLUSIONS
Although BMI is a significant independent predictor of inhibin B levels, the relationship between BMI and inhibin B changes with advancing menopause stage. These data provide additional evidence that obesity influences hormones during the menopause transition.
Gracia
Clarisa R
CR
Department of Obstetrics/Gynecology , University of Pennsylvania School of Medicine, Philadelphia, PA 19104, USA. cgarcia@obgyn.upenn.edu
Freeman
Ellen W
EW
Sammel
Mary D
MD
Lin
Hui
H
Nelson
Deborah B
DB
D000328:Adult; D000367:Age Factors; D000375:Aging / Q000502:physiology; D044383:Black People; D015992:Body Mass Index; D005260:Female; D005640:Follicle Stimulating Hormone / Q000097:blood; D005500:Follow-Up Studies; D006801:Humans; D007265:Inhibins / Q000097:blood*; D008593:Menopause / Q000502:physiology*; D008875:Middle Aged; D015999:Multivariate Analysis; D009765:Obesity / Q000097:blood / Q000503:physiopathology*; D011446:Prospective Studies; D011795:Surveys and Questionnaires; D044465:White People
C422364:inhibin B; D007265:Inhibins; D005640:Follicle Stimulating Hormone