Show simple item record

dc.contributor.authorVreede, Andrew P
dc.contributor.authorJones, Andrea N
dc.contributor.authorHansen, Karen E
dc.date.accessioned2015-09-01T18:47:07Z
dc.date.available2015-09-01T18:47:07Z
dc.date.issued2015-07-31
dc.identifier.citationNutrition Journal. 2015 Jul 31;14(1):73
dc.identifier.urihttp://dx.doi.org/10.1186/s12937-015-0065-5
dc.identifier.urihttp://hdl.handle.net/10724/32072
dc.description.abstractAbstract Background Low fractional calcium absorption (FCA) contributes to osteoporosis but is not measured clinically, as the gold-standard method requires administration of two calcium tracers and a subsequent 24-h urine collection. We evaluated alternate methods to measure FCA, compared to the gold standard method. Methods We administered two stable calcium isotope tracers (~8 mg oral 44Ca and ~3 mg intravenous 42Ca) with breakfast to 20 fasting post-menopausal women (Cohort 1) 59 ± 7 years old with vitamin D insufficiency. We measured subsequent calcium isotope concentrations in 24-h urine samples and serum collected 1, 3 and 5 h post tracer administration during an inpatient research stay. We assessed the candidate serum estimates in a second cohort of 9 women with similar characteristics. Methods of measuring FCA were compared using correlation coefficients and Bland-Altman tests. Results FCA estimated from a 3-h serum sample correlated highest with the levels from the 24-h urine collection (ρ 0.78, p < 0.001), but explained only 58 % of the variance in FCA. The total variance explained by 3-h estimates improved to 61 % with incorporation of glomerular filtration rate (GFR). FCA estimates from the 3-h serum measurement were assessed in a second group of nine women (Cohort 2) 60 ± 7 years old. In this cohort, however, FCA estimated by 3-h serum isotope levels did not correlate with gold-standard FCA measurements, whether determined with (ρ 0.02, p = 0.97) or without GFR values (ρ 0.03, p = 0.93). By contrast, FCA in Cohort 2 correlated best with 5-h serum isotope levels (ρ 0.75, p = 0.02). Conclusions We conclude that serum isotope levels correlate with true fractional calcium absorption, but do not reliably estimate FCA when analyzed using Bland-Altman tests, compared to gold-standard methods. Trial registration ClinicalTrials.gov.Identifier: NCT00933244
dc.titleCan serum isotope levels accurately measure intestinal calcium absorption compared to gold-standard methods?
dc.typeJournal Article
dc.date.updated2015-07-31T03:50:31Z
dc.language.rfc3066en
dc.rights.holderVreede et al.


Files in this item

Thumbnail

This item appears in the following Collection(s)

Show simple item record