Influence of age and sex steroids on bone density

Authors: K A Ward S R Pye J E Adams S Boonen D Vanderschueren H Borghs J Gaytant E Gielen G Bartfai F F Casanueva J D Finn G Forti A Giwercman T S Han I T Huhtaniemi K Kula F Labrie M E J Lean N Pendleton M Punab A J Silman F C W Wu T W O’Neill The EMAS study group

Publish Date: 2010/10/30

Volume: 22, Issue: 5, Pages: 1513-1523

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Abstract

The influence of age and sex steroids on bone density and geometry of the radius was examined in two European Caucasian populations Agerelated change in bone density and geometry was observed In older men bioavailable oestradiol may play a role in the maintenance of cortical and trabecular bone mineral density BMDEuropean Caucasian men aged 40–79 years were recruited from population registers in two centres Manchester UK and Leuven Belgium for participation in the European Male Ageing Study Total testosterone T and oestradiol E2 were measured by mass spectrometry and the free and bioavailable fractions calculated Peripheral quantitative computed tomography was used to scan the radius at distal 4 and midshaft 50 sitesThree hundred thirtynine men from Manchester and 389 from Leuven mean ages 602 and 600 years respectively participated At the 50 radius site there was a significant decrease with age in cortical BMD bone mineral content BMC cortical thickness and muscle area whilst medullary area increased At the 4 radius site trabecular and total volumetric BMD declined with age Increasing bioavailable E2 bioE2 was associated with increased cortical BMD 50 radius site and trabecular BMD 4 radius site in Leuven but not Manchester men This effect was predominantly in those aged 60 years and over In older Leuven men bioavailable testosterone Bio T was linked with increased cortical BMC muscle area and SSI 50 radius site and total area 4 radius siteThere is agerelated change in bone density and geometry at the midshaft radius in middleaged and elderly European men In older men bioE2 may maintain cortical and trabecular BMD BioT may influence bone health through associations with muscle mass and bone areaThe EMAS Study Group Florence Gianni Forti Luisa Petrone Giovanni Corona Leuven Dirk Vanderschueren Steven Boonen Herman Borghs Lodz Krzysztof Kula Jolanta SlowikowskaHilczer Renata WalczakJedrzejowska London Ilpo Huhtaniemi Malmö Aleksander Giwercman Manchester Frederick Wu Alan Silman Terence O’Neill Joseph Finn Philip Steer Abdelouahid Tajar David Lee Stephen Pye Santiago Felipe Casanueva Mary Lage Szeged Gyorgy Bartfai Imre Földesi Imre Fejes Tartu Margus Punab Paul Korrovitz Turku Min JiangOsteoporosis in men is an increasing but underappreciated clinical and public health problem with the lifetime risk of fracture in men at age 50 years estimated at 21 1 As in women increasing age is one of the major determinants of osteoporosis and fracture risk in men Most studies examining changes in bone health with age have focused on “areal” bone mineral density g/cm2 BMDa 2 as measured by dualenergy Xray absorptiometry DXA 3 4 5 6 There are limitations however in assessment of bone health using DXA In particular DXA tends to overestimate BMD in larger and underestimate in smaller bones Furthermore bone strength and susceptibility to fracture is influenced not only by the bone mineral content BMC but also bone shape and mineral distribution and the loading conditions to which the bone is subjected Peripheral quantitative computed tomography pQCT allows assessment of both bone geometry and material properties including volumetric density BMD In contrast to agerelated changes in DXA BMDa in men there are relatively few data concerning change in BMD as assessed by pQCT and bone structure with ageLevels of sex steroids are known to be associated with BMDa as assessed using DXA and also rate of bone loss 7 8 9 10 11 12 13 The contribution of oestradiol E2 to BMD has been reasonably well established but the effect of testosterone T is less clear as are the effects of sex hormones on bone structural parameters Khosla et al 9 14 showed that oestradiol E2 was the most constant predictor of BMD and geometry measured by QCT with the effect being more marked in elderly men as agerelated declines in sex steroids become relevant Similarly in the MINOS cohort E2 was related to DXA BMDa cortical thickness and area 15 There is some evidence to suggest a threshold effect of oestrogen particularly in cortical bone below which the male skeleton may suffer oestrogenrelated bone loss similar to that in the post menopausal female—the threshold level being the median value of bioavailable bio E2 30 pM in older 60 years men 8 14 Testosterone T has been linked with cortical and trabecular BMD 14 16 with conflicting data on effects on bone geometry Some studies have observed an association between testosterone and bone loss in males 13 whilst others have shown little or no effect be it assessing BMDa or increased fracture risk 15 17 18 19 geometric parameters were not reported in these studies

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