Oxytocin, a new determinant of bone mineral density in post-menopausal women: analysis of the OPUS cohort.
BACKGROUND
Oxytocin (OT), a neurohypophysial hormone regulated by estrogen and leptin, may play a role in bone metabolism in humans as suggested by animal studies. This study assessed the relationship between OT and bone status in a large population of postmenopausal women.


METHODS
Subjects were included in the Osteoporosis and Ultrasound study, a 6-year prospective study in a population-based cohort. Final visit data were used for this cross-sectional study. OT, leptin, and estradiol serum levels were measured in 1097 postmenopausal women and compared with bone mineral density (BMD), fractures, and the bone turnover markers (BTMs) procollagen type 1 N-terminal propeptide, bone alkaline phosphatase, and C-telopeptide of type 1 collagen.


RESULTS
The median age was 70.8 years, 16% were osteoporotic, 48% were osteopenic, and 29% had at least one fracture. The OT serum level was related to spine (r = +0.12, P = .0002) and total hip BMD (r = +0.21, P < .0001) and with BTM (procollagen type 1 N-terminal propeptide: r = -0.13, P < .0001, bone alkaline phosphatase: r = -0.07, P = .02, C-telopeptide of type 1 collagen: r = -0.18, P < .0001). The relationship of OT with BMD was independent of BTM. After adjustment for confounding factors, the correlation between OT serum level and BMD remains significant at the hip in women with unmeasurable estradiol or leptin above the median value. There was no significant relationship between OT serum levels and fractures.


CONCLUSIONS
High OT levels are associated with high BMD, especially at the hip in women with low estradiol or high leptin serum levels. The mechanism may be explained by the effect of OT on bone turnover.
Department of Rheumatology (V.B., H.B.Y., L.E.-Z.), Nice University Hospital, Archet Hospital, Faculté de Médecine (V.B., L.E.-Z., E.-Z.A.), University Nice Sophia Antipolis, Department of Hormonolgy (P.P.-F., H.B.Y., S.F.), Nice University Hospital, St Roch Hospital, and Department of Clinical Research (E.F.), Nice University Hospital, Cimiez Hospital, Nice F-06003, France; Department of Rheumatology (C.R., S.K.), INSERM, Unité 1153, Paris Descartes University, Cochin Hospital, F-75014 Paris, France; Academic Unit of Bone Metabolism (R.E., F.G.), University of Sheffield, Sheffield S10 2JF, United Kingdom; Centre National de la Recherche Scientifique (H.B.Y., E.-Z.A.), Institut de Biologie Valrose Unité Mixte de Recherche 7277, and INSERM (H.B.Y., E.-Z.A.), iBV, Unité 1091, F-06100 Nice, France; and INSERM (C.-L.B.), Unité 658, Centre Hospitalier Régional d'Orléans, F-45032 Orléans Cedex 1, France.
Véronique
V
Breuil
Patricia
P
Panaia-Ferrari
Eric
E
Fontas
Christian
C
Roux
Sami
S
Kolta
Richard
R
Eastell
Hedi
H
Ben Yahia
Sylvie
S
Faure
Fatma
F
Gossiel
Claude-Laurent
CL
Benhamou
Liana
L
Euller-Ziegler
Ez-Zoubir
EZ
Amri
D000368:Aged; D015415:Biomarkers / Q000097:blood; D015519:Bone Density; D016723:Bone Remodeling; D015331:Cohort Studies; D003430:Cross-Sectional Studies; D005260:Female; D050723:Fractures, Bone / Q000097:blood / Q000175:diagnosis; D006801:Humans; D008875:Middle Aged; D015663:Osteoporosis, Postmenopausal / Q000097:blood / Q000175:diagnosis*; D010121:Oxytocin / Q000097:blood*; D017698:Postmenopause / Q000097:blood*; D011379:Prognosis
D015415:Biomarkers; D010121:Oxytocin