title: Correlates of osteoprotegerin levels in women and men.
abstract: Osteoprotegerin (OPG) is a potent antiresorptive molecule that binds the final effector for osteoclastogenesis, receptor activator of NF-kappaB ligand (RANK-L). OPG production is regulated by a number of cytokines and hormones, including sex steroids, but there are few data on age and gender effects on circulating serum OPG levels, as well as possible relationships between OPG levels and bone turnover markers or bone mineral density (BMD). Thus, we measured serum OPG levels in an age-stratified, random sample of men (n = 346 age range, 23-90 years) and women (n = 304; age range 21-93 years) and related them to sex steroid levels, bone turnover markers and BMD. Serum OPG levels increased with age in both men (R = 0.39, p < 0.001) and women (R = 0.18, p < 0.01). Premenopausal women had higher OPG levels than men under age 50 years (171 +/- 6 pg/ml vs 134 +/- 6 pg/ml, respectively, p < 0.001), whereas serum OPG levels were no different in postmenopausal women compared with men = 50 years (195 +/- 7 pg/ml vs 188 +/- 7 pg/ml, respectively, p = 0.179). OPG levels correlated inversely with serum bioavailable testosterone levels in men = 50 years (R = -0.27, p < 0.001), but no associations were present with either estrogen or testosterone levels in the women. In the men, there was a trend for OPG levels to be associated positively with bone resorption markers and inversely with BMD. Collectively, the gender difference in OPG levels suggests that sex steroids may regulate OPG production in vivo, as has been found in vitro. Moreover, OPG production may also rise with increases in bone turnover, probably as a homeostatic mechanism to limit bone loss. Further studies directly testing these hypotheses should provide additional insights into the potential role of OPG in bone loss related to aging and sex steroid deficiency.
authors.affiliation: Department of Internal Medicine, Mayo Clinic and Foundation, Rochester, MN 55905, USA. Khosla.Sundeep@Mayo.Edu
authors.forename: S
authors.initials: S
authors.lastname: Khosla
authors.forename: H M
authors.initials: HM
authors.lastname: Arrighi
authors.forename: L J
authors.initials: LJ
authors.lastname: Melton
authors.forename: E J
authors.initials: EJ
authors.lastname: Atkinson
authors.forename: W M
authors.initials: WM
authors.lastname: O'Fallon
authors.forename: C
authors.initials: C
authors.lastname: Dunstan
authors.forename: B L
authors.initials: BL
authors.lastname: Riggs
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000375:Aging / Q000097:blood*; D016723:Bone Remodeling / Q000502:physiology; D004797:Enzyme-Linked Immunosorbent Assay; D004958:Estradiol / Q000097:blood; D005260:Female; D006023:Glycoproteins / Q000097:blood*; D006801:Humans; D008297:Male; D008875:Middle Aged; D053244:Osteoprotegerin; D017698:Postmenopause / Q000502:physiology; D017697:Premenopause / Q000502:physiology; D018160:Receptors, Cytoplasmic and Nuclear / Q000097:blood*; D018124:Receptors, Tumor Necrosis Factor; D012727:Sex Characteristics; D018709:Statistics, Nonparametric; D013739:Testosterone / Q000097:blood
chemical_list: D006023:Glycoproteins; D053244:Osteoprotegerin; D018160:Receptors, Cytoplasmic and Nuclear; D018124:Receptors, Tumor Necrosis Factor; C506030:TNFRSF11B protein, human; D013739:Testosterone; D004958:Estradiol