Capillaries prevail at bone remodelling sites in adult human bone

Abstracts / Bone 48 (2011) S187–S203 fracture-type in the Austrian population has not yet been assessed so far. Objectives: The aim of the present study was to assess the incidence of humeral fractures in the Austrian population aged 50 years and above, over a period of two decades (1989–2008), and to estimate the trend in average annual change. Methods: The number of humeral fractures was obtained from the Austrian Hospital Discharge Registry (AHDR) for the entire population ≥ 50 years of age. A correction factor for multiple registrations of the same diagnosis was determined. Incidence rates (cases per 100,000) of humeral fracture were calculated in 5-year age intervals. To analyze the overall change in this type of fracture for the period, average annual changes expressed as incidence rate ratios (ΔIRRs, using negative binomial regression models) were calculated. Results: ( Fig. 1). The age standardized incidence in the entire population increased over the period of 20 years. The ΔIRR for the whole period was 1.043 (1.029–1.057; 95% CI) in women, 1.008 (1.004–1.013; 95% CI) in men, and 1.024 (1.017–1.031; 95%CI) in the entire population. Conclusion: The present study indicates that age-adjusted incidence rates in humeral fractures in the Austrian population, 50 yrs of age and above, are high. In contrast to trends in hip fracture incidence rates, IRRs for humeral fractures exhibit a continuing positive trend, with no evidence of a downward trend or levelling-off in the recent past.

This article is part of a Special Issue entitled ECTS 2011. Disclosure of interest: None declared.

doi:10.1016/j.bone.2011.03.449

PP289-S Dietary potassium and bone health: A systematic review and meta-analysis H. Lambert a, ⁎, V. Boyd a, A. Darling a, D. Torgerson b, P. Burckhardt c, L. Frassetto d, S. Lanham-New a a Nutritional Sciences Division, Faculty of Health and Medical Sciences, University of Surrey, Guildford, UK b Centre for Health Economics, University of York, York, United Kingdom c Clinique Bois-Cerf, Lausanne, Switzerland d CTSI Clinical Research Centre, San Francisco, USA Abstract: There have been many recent studies researching the effect of potassium on bone health1. The Western diet is an acidic one, and including potassium-rich foods such as fruit and vegetables in the diet may help counteract the detrimental effect acid can have on the skeleton2. Bone acts as a ‘buffer’ due to its alkalinity, but there is at present no consensus as to whether potassium-rich foods could be ‘bone sparing’. This study aimed to collate the data produced and conduct a systematic review and meta-analysis on the effects of potassium on bone health indices. The following words were entered into Pubmed: ‘potassium’ and ‘citrate’, bicarbonate, ‘health’ ‘bone’ ‘fracture’ and ‘density’ and searched for all cross-sectional, longitudinal and intervention studies. 1922 papers were identified. Of the 75 applicable studies, 27 were eligible to be included in the systematic review, and eight in the meta-analysis. For cross-sectional studies, the systematic review showed a positive correlation between potassium intake and BMD for all sub-groups combined (r2 = 0.0033) and for all sites combined 2 (r = 0.007). For longitudinal studies there was a positive correlation between dietary potassium intakes and BMD (r2 = 0.007). Meta-analysis showed the following significant associations: Potassium bicarbonate and urinary calcium (p = 0.009, mean difference (95%CI)− 1.27(−2.22– 0.31)). Potassium and urinary calcium (p= 0.02, mean difference (95%CI)− 38.36(−70.24– 6.47)). Potassium and hydroxyproline (p= 0.04, mean difference (95%CI)− 3.63(−7.06–0.21)). Potassium and bone resorption (p = 0.03, mean difference (95%CI)− 0.48(−0.91–0.05)). These data suggest that potassium has a small (~1%) effect on bone health. Further research is needed into the longer term effects of potassium on fracture risk as well as further intervention studies using more rigorous methodology and a wider range of dependent variables. However, these preliminary results suggest a positive effect of potassium on bone, which may have an impact on the prevention and treatment of osteoporosis. This article is part of a Special Issue entitled ECTS 2011. Disclosure of interest: None declared.

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References [1] Chan RS, Woo J, Chan DC, Cheung CS, Lo DH. Estimates of net endogenous acid production and intake of bone health-related nutrients in Hong Kong Chinese adolescents. Eur J Clin Nutr Jan 30 2008. [2] Thorpe M, Mojtahedi MC, Chapman-Novakofski K, McAuley E, Evans EM. A positive association of lumbar spine bone mineral density with dietary protein is suppressed by a negative association with protein sulfur. J Nutr Jan 2008;138(1):80–5. doi:10.1016/j.bone.2011.03.450

PP290-M Capillaries prevail at bone remodelling sites in adult human bone H.B. Kristensen a, ⁎, T.L. Andersen a, N. Marcussen b, L. Rolighed c, J.-M. Delaissé a a Department of Clinical Cell Biology, Vejle Hospital/University of Southern Denmark, Vejle, Denmark b Department of Pathology, University of Southern Denmark, Odense, Denmark c Medical Endocrinology department C, Aarhus Sygehus, Tage-Hansens Gade 2, Aarhus, Denmark Abstract: Osteogenesis in bone development and fracture healing depends critically on vascularisation, but it is not known whether there is a relation between vascularisation and remodelling of adult human cancellous bone. Here, we investigate how capillaries and a putative osteoblast progenitor marker, smooth muscle actin (SMA) distribute above eroded, bone forming and quiescent surfaces and relate to the presence of the bone remodelling compartment (BRC) canopy. The study includes nine iliac crest biopsies from control patients. Adjacent sections were stained in such a way that information from histomorphometry and immunohistochemistry could be combined. The distance from the bone or canopy to the CD34 class II stained capillary was measured on an orthogonal line up to 100 μm into the bone marrow, and the number of randomized hits were summed up for each surface, recording also whether a BRC canopy was present or not. The zone spanning 100 μm above eroded surfaces (ES) and osteoid surfaces (OS), compared to that above quiescent surfaces (QS), show respectively a 1.79 and 1.3 times higher capillary density in the absence of the BRC canopy, and a 2.55 and 1.8 higher level in its presence. Moreover light microscope-assessed capillary-canopy contacts are as much as 3.39 and 2.35 times higher above respectively ES and OS, compared to capillary-QS contacts. Densities above remodelling sites decrease progressively with increased distance from the bone surface, and at a 50 μm distance, they equal the level above QS. Electron microscopy shows that the capillaries line the BRC canopy at less than 1 μm distance between the two membranes, and that cells perform diapedesis through the capillary wall and the BRC canopy. The density of SMA in the BRC canopy is 2.56 times higher above ES compared to QS, and on the bone surface the density is 1.47 times higher on ES, compared to OS. Furthermore, when SMA is not expressed in the canopy it is very rarely expressed on the bone surface below the canopy. All the reported differences are highly statistically significant. These data support that capillaries are an important component of the mechanism controlling adult human cancellous bone remodelling. The higher levels of capillaries above ES compared to OS suggest that capillaries are present from the beginning of the remodelling process, thereby participating in recruitment of osteoclast and osteoblast progenitors as suggested by our observations of diapedesis and SMA distribution. This article is part of a Special Issue entitled ECTS 2011. Disclosure of interest: None declared. doi:10.1016/j.bone.2011.03.451

PP291-T Prevalence of osteoporosis in the Korean population based on the fourth Korea National Health and Nutrition Examination Survey (KNHANES IV), 2008–2009 I. Joo a, ⁎, H. Oh a, B. Yu b, K. Kim c, H. Choi d a Family Medicine, Cheil General Hospital, Kwandong University, Seoul, Republic of Korea b Family Medicine, Gonyang University Hospital, Daejeon, Republic of Korea c Family Medicine, Catholic University Hospital, Seoul, Republic of Korea d Family Medicine, Eulji University, Daejeon, Republic of Korea Abstract: Context: In 2008, the Ministry of Health and Welfare in Korea started a nationwide, cross-sectional survey measuring the BMD (g/cm2) at the lumbar spine (L2–4), femoral neck, trochanter, and Ward's triangle by dual-energy X-ray absorptiometry (DXA) (Hologic Discovery, Hologic, USA) for the first time. Objective: To investigate the prevalence of osteoporosis in Korea, we analyzed age-related changes of BMD and compared with that of U.S participant and Japanese. Participants, design and setting: Bone mineral measurements were obtained from 4660 men and 5670 women aged 19 years and older through the