Searchable abstracts of presentations at key conferences in endocrinology
Endocrine Abstracts (2015) 38 P11 | DOI: 10.1530/endoabs.38.P11

SFEBES2015 Poster Presentations Bone (18 abstracts)

The effect of oestradiol circadian rhythm on the bone mineral density of adult males

Sajini Wijetilleka 1 , Muhammad Khan 1 , Aung Mon 2 , Frank Joseph 3 , William Fraser 4 & Jiten Vora 1


1Royal Liverpool Hospital, Liverpool, UK; 2University Hospital Aintree, Liverpool, UK; 3Countess of Chester Hospital, Chester, UK; 4Norwich Medical School, Norwich, UK.


Background: Circulating levels of total oestradiol (E2) decrease with age in adult males; the effect of altered E2 circadian rhythm is uncertain. We hypothesised that age-related changes in the circadian rhythm contribute to decreased BMD in older males and investigated this.

Methods: Nineteen subjects were studied: six young-healthy (YH) males (mean age (years) 27.3±4.6) with normal BMD, eight older-healthy (OH) males (mean age (years) 70.5±2.1) with normal BMD, and five older males with osteoporosis (OO) (mean age (years) 75±2.9). Groups were matched for body weight and BMI; subjects excluded had histories of bisphosphonate, corticosteroid, calcium, and/or vitamin D use and skeletal disorders. Volunteers were hospitalised with blood samples obtained every 30 min over a 24-h period. Levels of total E2 and bioavailable E2 were calculated. Circadian rhythm was analysed.

Results: Total 24-h mean bioavailable E2 was less in the OH cohort compared to the YH group (16.7±2.2 pmol/l vs 26.3±3.6 pmol/l; P<0.0001); 24-h mean total E2 concentrations reflected this pattern (P<0.0001). The OO group had significantly less 24-h mean bioavailable E2 than the OH cohort (12.5±1.8 pmol/l vs 16.7±2.2 pmol/l; P<0.0001). IGF1 levels were significantly greater in the OH compared to the OO cohorts (group mean MESOR 112±24 μg/l vs 72±13 μg/l). Total oestrogen demonstrated a concerted circadian rhythm in all three groups, but bioavailable oestrogen did not demonstrate circadian rhythmicity in older men with decreased BMD.

Conclusion: Twenty-four hours mean bioavailable E2 and IGF1 levels are significantly lower in older men with osteoporosis compared to healthy counterparts. Osteoporotic subjects demonstrated a disrupted circadian rhythm with respect to bioavailable oestrogen. Our study demonstrates the role of circadian E2 rhythms in the maintenance of BMD.

Volume 38

Society for Endocrinology BES 2015

Edinburgh, UK
02 Nov 2015 - 04 Nov 2015

Society for Endocrinology 

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