Three-Phase Model Harmonizes Estimates of the Maximal Suppression of Parathyroid Hormone by 25-Hydroxyvitamin D in Persons 65 Years of Age and Older Durazo-Arvizu, Ramon Dawson-Hughes, Bess Carriquiry, Alicia Sempos, Christopher Yetley, Elizabeth Looker, Anne Cao, Guichan Harris, Susan Burt, Vicki Carriquiry, Alicia Picciano, Mary
dc.contributor.department Statistics 2018-02-17T06:24:05.000 2020-07-02T06:57:49Z 2020-07-02T06:57:49Z 2010-01-01
dc.description.abstract <p>The concentration or threshold of 25-hydroxyvitamin D [25(OH)D] needed to maximally suppress intact serum parathyroid hormone (iPTH) has been suggested as a measure of optimal vitamin D status. Depending upon the definition of maximal suppression of iPTH and the 2-phase regression approach used, 2 distinct clusters for a single 25(OH)D threshold have been reported: 16-20 ng/mL (40-50 nmol/L) and 30-32 ng/mL (75-80 nmol/L). To rationalize the apparently disparate published results, we compared thresholds from several regression models including a 3-phase one to estimate simultaneously 2 thresholds before and after adjusting for possible confounding for age, BMI, glomerular filtration rate, dietary calcium, and season (April-September vs. October-March) within a single data set, i.e. data from the Tufts University Sites Testing Osteoporosis Prevention/Intervention Treatment study, consisting of 181 men and 206 women (total n = 387) ages 65-87 y. Plasma 25(OH)D and serum iPTH concentrations were (mean ± SD) 22.1 ± 7.44 ng/mL (55.25 ± 18.6 nmol/L) and 36.6 ± 16.03 pg/mL (3.88 ± 1.7 pmol/L), respectively. The 3-phase model identified 2 thresholds of 12 ng/mL (30 nmol/L) and 28 ng/mL (70 nmol/L); similar results were found from the 2-phase models evaluated, i.e. 13-20 and 27-30 ng/mL (32.5-50 and 67.5-75 nmol/L) and with previous results. Adjusting for confounding did not change the results substantially. Accordingly, the 3-phase model appears to be superior to the 2-phase approach, because it simultaneously estimates the 2 threshold clusters found from the 2-phase approaches along with estimating confidence limits. If replicated, it may be of both clinical and public health importance.</p>
dc.description.comments <p>This article is from <em>Journal of Nutrition</em> 140 (2010): 595, doi: <a href="" target="_blank">10.3945/jn.109.116681</a>.</p>
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dc.identifier archive/
dc.identifier.articleid 1036
dc.identifier.contextkey 7858412
dc.identifier.s3bucket isulib-bepress-aws-west
dc.identifier.submissionpath stat_las_pubs/37
dc.language.iso en
dc.source.bitstream archive/|||Fri Jan 14 23:49:22 UTC 2022
dc.source.uri 10.3945/jn.109.116681
dc.subject.disciplines Biochemical Phenomena, Metabolism, and Nutrition
dc.subject.disciplines Public Health
dc.subject.disciplines Statistics and Probability
dc.subject.keywords 25 hydroxyvitamin D
dc.subject.keywords calcium
dc.subject.keywords parathyroid hormone
dc.subject.keywords body mass
dc.subject.keywords controlled study
dc.subject.keywords elderly care
dc.subject.keywords glomerulus filtration rate
dc.subject.keywords hormone determination
dc.subject.keywords mathematical model
dc.subject.keywords maximum allowable concentration
dc.title Three-Phase Model Harmonizes Estimates of the Maximal Suppression of Parathyroid Hormone by 25-Hydroxyvitamin D in Persons 65 Years of Age and Older
dc.type article
dc.type.genre article
dspace.entity.type Publication
relation.isAuthorOfPublication 6ddd5891-2ad0-4a93-89e5-8c35c28b0de4
relation.isOrgUnitOfPublication 264904d9-9e66-4169-8e11-034e537ddbca
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