title: Higher serum free testosterone concentration in older women is associated with greater bone mineral density, lean body mass, and total fat mass: the cardiovascular health study.
abstract: BACKGROUND
  The physiological importance of endogenous testosterone (T) in older women is poorly understood.
  
  
  OBJECTIVE
  The aim of the study was to determine the association of higher total and free T levels with bone mineral density (BMD), lean body mass, and fat mass in elderly women.
  
  
  METHODS
  Total and free T were measured using sensitive assays in 232 community-dwelling women aged 67-94 yr who were enrolled in the Cardiovascular Health Study and had dual-energy x-ray absorptiometry scans. Cross-sectional analyses were performed to examine associations between total and free T and BMD and body composition.
  
  
  RESULTS
  In adjusted models, total T was directly associated with BMD at the lumbar spine (P = 0.04) and hip (P = 0.001), but not body composition outcomes, in all women, and after excluding estrogen users and adjusting for estradiol (P = 0.04 and 0.01, respectively). Free T was positively related to hip BMD, lean body mass, and body fat (all P < 0.05), with more than 10% differences in each outcome between women at the highest and lowest ends of the free T range, with attenuation after excluding estrogen users and adjusting for estradiol.
  
  
  CONCLUSIONS
  In the setting of the low estradiol levels found in older women, circulating T levels were associated with bone density. Women with higher free T levels had greater lean body mass, consistent with the anabolic effect of T, and, in contrast to men, greater fat mass. Mechanistic studies are required to determine whether a causal relationship exists between T, bone, and body composition in this population and the degree to which any T effects are estrogen-independent.
authors.affiliation: Division of Endocrinology, University of Pennsylvania School of Medicine, Philadelphia, Pennsylvania 19104, USA.
authors.forename: Chevon M
authors.initials: CM
authors.lastname: Rariy
authors.forename: Sarah J
authors.initials: SJ
authors.lastname: Ratcliffe
authors.forename: Rachel
authors.initials: R
authors.lastname: Weinstein
authors.forename: Shalender
authors.initials: S
authors.lastname: Bhasin
authors.forename: Marc R
authors.initials: MR
authors.lastname: Blackman
authors.forename: Jane A
authors.initials: JA
authors.lastname: Cauley
authors.forename: John
authors.initials: J
authors.lastname: Robbins
authors.forename: Joseph M
authors.initials: JM
authors.lastname: Zmuda
authors.forename: Tamara B
authors.initials: TB
authors.lastname: Harris
authors.forename: Anne R
authors.initials: AR
authors.lastname: Cappola
mesh_terms: D000273:Adipose Tissue / Q000033:anatomy & histology* / Q000473:pathology; D000368:Aged; D000369:Aged, 80 and over; D015992:Body Mass Index; D015519:Bone Density / Q000502:physiology; D002320:Cardiovascular Physiological Phenomena; D015331:Cohort Studies; D005260:Female; D006262:Health; D006801:Humans; D009929:Organ Size; D009994:Osmolar Concentration; D015663:Osteoporosis, Postmenopausal / Q000097:blood / Q000453:epidemiology / Q000473:pathology; D013739:Testosterone / Q000032:analysis / Q000097:blood*; D013851:Thinness / Q000097:blood* / Q000473:pathology; D015854:Up-Regulation
chemical_list: D013739:Testosterone