Oral Presentation The Annual Scientific Meeting of the Endocrine Society of Australia and the Society for Reproductive Biology 2014

Higher bone remodelling rates are associated with reduced diabetes risk and lower estradiol concentrations in older men. (#200)

Bu B Yeap 1 2 , Helman Alfonso 3 , Paul Chubb 4 , Richard Gauci 2 , Elizabeth Byrnes 5 , John P Beilby 6 , David J Handelsman 7 , Peter R Ebeling 8 , Leon Flicker 1 9 , Paul E Norman 10
  1. School of Medicine, University of Western Australia, Perth, WA, Australia
  2. Department of Endocrinology and Diabetes, Fremantle and Fiona Stanley Hospitals, Perth, WA, Australia
  3. School of Public Health, Curtin University, Perth, WA, Australia
  4. PathWest Laboratory Medicine, Fremantle and Royal Perth Hospitals, Perth, WA, Australia
  5. PathWest Laboratory Medicine, Sir Charles Gairdner Hospital, Perth, WA, Australia
  6. PathWest Laboratory Medicine, Sir Charles Gairdner Hospital, Perth, WA, Australia
  7. ANZAC Research Institute, University of Sydney, Sydney, NSW, Australia
  8. Department of Medicine, Monash University, Melbourne, Victoria, Australia
  9. School of Medicine, University of Western Australia, Perth, WA, Australia
  10. School of Surgery, University of Western Australia, Perth, WA, Australia

Context

Osteocalcin (OC) is an osteoblast-derived peptide circulating in undercarboxylated and γ-carboxylated forms. In mice undercarboxylated osteocalcin (ucOC) modulates insulin secretion and sensitivity, and increases testosterone (T) secretion from Leydig cells. Its relevance to humans is unclear.

Objective

We examined cross-sectional associations of ucOC, total OC and other bone turnover markers with diabetes and sex hormones.

Participants

Community-dwelling men aged 70-89 years resident in Perth, Western Australia. 

Outcome measures

Serum total OC, N-terminal propeptide of type I collagen (P1NP) and collagen type I C-terminal cross-linked telopeptide (CTX) were measured by immunoassay, and ucOC by hydroxyapatite binding. T and estradiol (E2) were assayed by mass spectrometry in early morning samples.

Results

There were 2,966 men in the analysis after excluding men with osteoporosis, on bisphosphonates, glucocorticoids or warfarin, and conditions or medications affecting sex hormones. After adjusting for age, smoking, BMI, waist-hip ratio, hypertension, dyslipidemia, creatinine, vitamin D and medical comorbidities, higher ucOC was associated with reduced prevalence of diabetes (odds ratio [OR]=0.55, 95% confidence interval [CI]=0.47-0.64, p<0.001 per 1 SD increase ucOC). Similar results were seen for total OC (OR=0.60, 95% CI=0.50-0.72, p<0.001), P1NP (0.64, 0.54-0.76, p<0.001) and CTX (0.60, 0.52-0.69, p<0.001) but not ucOC/total OC. E2 was inversely associated with ucOC (coefficient -0.04, p=0.031), total OC (-0.05, p=0.001) and CTX (-0.04, p=0.016); and positively with ucOC/total OC (0.05, p=0.002). T was not associated with ucOC, total OC, P1NP, CTX or ucOC/total OC (all p>0.05).

Conclusions

Higher bone remodelling rates are associated with reduced diabetes risk in older men. Although higher ucOC is associated with reduced diabetes risk, it acts as a marker of increased bone remodelling rate, rather than possessing a specific effect. E2, but not T, is inversely associated with bone turnover markers. We found no evidence ucOC, or ucOC/total OC modulates circulating T in men.