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Eisenhauer A, Müller M, Heuser A, Kolevica A, Glüer CC, Both M, Laue C, Hehn UV, Kloth S, Shroff R, Schrezenmeir J. Calcium isotope ratios in blood and urine: A new biomarker for the diagnosis of osteoporosis. Bone Rep 2019; 10:100200. [PMID: 30997369 PMCID: PMC6453776 DOI: 10.1016/j.bonr.2019.100200] [Citation(s) in RCA: 32] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/02/2019] [Accepted: 03/10/2019] [Indexed: 11/30/2022] Open
Abstract
We assessed the potential of Calcium (Ca) isotope fractionation measurements in blood (δ44/42CaBlood) and urine (δ44/42CaUrine) as a new biomarker for the diagnosis of osteoporosis. One hundred post-menopausal women aged 50 to 75 years underwent dual-energy X-ray absorptiometry (DXA), the gold standard for determination of bone mineral density. After exclusion of women with kidney failure and vitamin D deficiency (<25 nmol/l) 80 women remained in the study. Of these women 14 fulfilled the standard diagnostic criteria for osteoporosis based on DXA. Both the δ44/42CaBlood (p < 0.001) and δ44/42CaUrine (p = 0.004) values were significantly different in women with osteoporosis (δ44/42CaBlood: −0.99 ± 0.10‰, δ 44/42CaUrine: +0.10 ± 0.21‰, (Mean ± one standard deviation (SD), n = 14)) from those without osteoporosis (δ44/42CaBlood: −0.84 ± 0.14‰, δ44/42CaUrine: +0.35 ± 0.33‰, (SD), n = 66). This corresponded to the average Ca concentrations in morning spot urine samples ([Ca]Urine) which were higher (p = 0.041) in those women suffering from osteoporosis ([Ca]Urine-Osteoporosis: 2.58 ± 1.26 mmol/l, (SD), n = 14) than in the control group ([Ca]Urine-Control: 1.96 ± 1.39 mmol/l, (SD), n = 66). However, blood Ca concentrations ([Ca]Blood) were statistically indistinguishable between groups ([Ca]Blood, control: 2.39 ± 0.10 mmol/l (SD), n = 66); osteoporosis group: 2.43 ± 0.10 mmol/l (SD, n = 14) and were also not correlated to their corresponding Ca isotope compositions. The δ44/42CaBlood and δ44/42CaUrine values correlated significantly (p = 0.004 to p = 0.031) with their corresponding DXA data indicating that both Ca isotope ratios are biomarkers for osteoporosis. Furthermore, Ca isotope ratios were significantly correlated to other clinical parameters ([Ca]Urine, ([Ca]Urine/Creatinine)) and biomarkers (CRP, CTX/P1NP) associated with bone mineralization and demineralization. From regression analysis it can be shown that the δ44/42CaBlood values are the best biomarker for osteoporosis and that no other clinical parameters need to be taken into account in order to improve diagnosis. Cut-off values for discrimination of subjects suffering from osteoporosis were − 0.85‰ and 0.16‰ for δ44/42CaBlood and δ44/42CaUrine, respectively. Corresponding sensitivities were 100% for δ44/42CaBlood and ~79% for δ44/42CaUrine. Apparent specificities were ~55% for δ44/42CaBlood and ~71%. The apparent discrepancy in the number of diagnosed cases is reconciled by the different methodological approaches to diagnose osteoporosis. DXA reflects the bone mass density (BMD) of selected bones only (femur and spine) whereas the Ca isotope biomarker reflects bone Ca loss of the whole skeleton. In addition, the close correlation between Ca isotopes and biomarkers of bone demineralization suggest that early changes in bone demineralization are detected by Ca isotope values, long before radiological changes in BMD can manifest on DXA. Further studies are required to independently confirm that Ca isotope measurement provide a sensitive, non-invasive and radiation-free method for the diagnosis of osteoporosis.
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Affiliation(s)
- A Eisenhauer
- GEOMAR Helmholtz Centre for Ocean Research Kiel, 24148 Kiel, Wischhofstr.1-3, Germany.,OSTEOLABS GmbH, c/o GEOMAR Helmholtz Centre for Ocean Research Kiel, 24148 Kiel, Wischhofstr.1-3, Germany
| | - M Müller
- University Medical Center Schleswig-Holstein (UKSH), Arnold-Heller-Str. 3, 24105 Kiel, Germany.,OSTEOLABS GmbH, c/o GEOMAR Helmholtz Centre for Ocean Research Kiel, 24148 Kiel, Wischhofstr.1-3, Germany
| | - A Heuser
- GEOMAR Helmholtz Centre for Ocean Research Kiel, 24148 Kiel, Wischhofstr.1-3, Germany.,OSTEOLABS GmbH, c/o GEOMAR Helmholtz Centre for Ocean Research Kiel, 24148 Kiel, Wischhofstr.1-3, Germany
| | - A Kolevica
- GEOMAR Helmholtz Centre for Ocean Research Kiel, 24148 Kiel, Wischhofstr.1-3, Germany.,OSTEOLABS GmbH, c/o GEOMAR Helmholtz Centre for Ocean Research Kiel, 24148 Kiel, Wischhofstr.1-3, Germany
| | - C-C Glüer
- Sektion Biomedizinische Bildgebung, Klinik für Radiologie und Neuroradiologie, Am Botanischen Garten 14, 24118 Kiel, Germany
| | - M Both
- Klinik für Neuroradiologie und Radiologie, (UKSH), Arnold-Heller-Str. 3, 24105 Kiel, Germany
| | - C Laue
- Clinical Research Center Kiel GmbH, Schauenburgerstraße 116, 24118 Kiel, Germany
| | - U V Hehn
- Medistat, GmbH, Kieler Straße 15, 24119 Kronshagen, Germany
| | - S Kloth
- OSTEOLABS GmbH, c/o GEOMAR Helmholtz Centre for Ocean Research Kiel, 24148 Kiel, Wischhofstr.1-3, Germany
| | - R Shroff
- Great Ormond Street Hospital for Children NHS Foundation Trust, London WC1N 3JH, United Kingdom of Great Britain and Northern Ireland
| | - J Schrezenmeir
- Clinical Research Center Kiel GmbH, Schauenburgerstraße 116, 24118 Kiel, Germany
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Ceglia L, Abrams SA, Harris SS, Rasmussen HM, Dallal GE, Dawson-Hughes B. Evaluation of an inexpensive calcium absorption index in healthy older men and women. Clin Endocrinol (Oxf) 2010; 72:22-5. [PMID: 19320650 PMCID: PMC4431538 DOI: 10.1111/j.1365-2265.2009.03576.x] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
OBJECTIVE Calcium absorption is an important determinant of calcium retention and bone metabolism. However, most methods of measuring calcium absorption, including the well-established dual stable isotope method, are costly and cumbersome to implement. We evaluated whether an oral calcium tolerance test (OCTT), which involves measuring calcium excretion in a fasting 2-h urine collection and two 2-h collections following an oral calcium dose, may be a useful index of calcium absorption in older adults consuming a fixed calcium intake of 30 mmol/day. DESIGN After a 10-day metabolic diet containing 30 mmol/day of calcium, subjects had calcium absorption measured using the dual stable isotope method and the OCTT. PARTICIPANTS Eleven healthy subjects aged 54-74 years. MEASUREMENTS Fractional calcium absorption (FCA), calcium excretion in a fasting 2-h urine collection and two 2-h collections in response to a 10-mmol calcium dose (total intake 30 mmol/day). RESULTS Calcium excretion from several combinations of the urine collections was examined in relation to FCA. The most predictive of FCA was calcium excretion 4 h following the calcium dose. This measure was significantly correlated with FCA (r = 0.735, P = 0.010), fitting 54% of the variability in FCA. CONCLUSION Urinary calcium excretion during the 4 h after a 10-mmol calcium dose is a useful index of calcium absorption among older adults consuming recommended calcium intakes. This test is inexpensive, easy to implement and potentially useful in large clinical studies.
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Affiliation(s)
- Lisa Ceglia
- Jean Mayer United States Department of Agriculture Human Nutrition Research Center on Aging, Tufts University, Boston, MA 02111, USA.
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Abrams SA, Hicks PD, Hawthorne KM. Higher serum 25-hydroxyvitamin D levels in school-age children are inconsistently associated with increased calcium absorption. J Clin Endocrinol Metab 2009; 94:2421-7. [PMID: 19383779 PMCID: PMC2708956 DOI: 10.1210/jc.2008-2587] [Citation(s) in RCA: 57] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
CONTEXT Increasing serum 25-hydroxyvitamin D (25-OHD) in adults may enhance calcium absorption (Ca-abs). There are few similar pediatric data leading to uncertainty about the optimal target for 25-OHD to maximize Ca-abs. OBJECTIVE Our objective was to evaluate the relationship between 25-OHD and Ca-abs in a large cohort of school-age children and adolescents. DESIGN We evaluated data from 439 Ca-abs measurements performed using dual-tracer stable isotope techniques conducted at our center over a 15-yr period in 251 healthy children, 4.9-16.7 yr of age. RESULTS Serum 25-OHD ranged from 28 to 197 nmol/liter (mean 85 +/- 2 nmol/liter) (sem). Total Ca-abs (intake times fractional absorption) were significantly correlated to 25-OHD in the whole population (r = 0.16, P = 0.001). This relationship was closer in the 197 studies in early puberty (Tanner 2 or 3, r = 0.35, P < 0.001) and not significant in pre- or late pubertal subjects. For the whole population, fractional Ca-abs adjusted for calcium intake were slightly but significantly higher at 25-OHD of 28-50 nmol/liter (0.344 +/- 0.019) compared with 25-OHD of 50-80 nmol/liter (0.280 +/- 0.014) or 25-OHD greater than 80 nmol/liter (0.297 +/- 0.015, P < 0.01 for each), suggesting adaptation to moderately low 25-OHD values. CONCLUSION There is no consistent pattern of relationship between 25-OHD and either fractional or total calcium absorption in school-age children. However, there appears to be a modest calcium absorptive response to higher 25-OHD during early puberty.
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Affiliation(s)
- Steven A Abrams
- United States Department of Agriculture/Agricultural Research Service, Children's Nutrition Research Center, Houston, Texas 77030, USA.
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