| Intra-individual variation in serum C-reactive protein over 4 years: an implication for epidemiologic studies. | |
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MedLine Citation:
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PMID: 20135215 Owner: NLM Status: MEDLINE |
Abstract/OtherAbstract:
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BACKGROUND: Data on long-term intra-individual variability in high-sensitivity C-reactive protein (hsCRP) are needed to determine whether one measurement adequately reflects usual levels in prospective studies of on the etiology of cancer and other chronic diseases; when not reflective, the ability to statistically detect modest to moderate associations is reduced. The authors estimated the size of this source of variability and consequent attenuation of the relative risk (RR). METHODS: High-sensitivity C-reactive protein (hsCRP) concentration was measured using a high-sensitivity immunoturbidometric assay in sera collected at years 2, 4, and 6 from 50 men in the placebo arm of the Prostate Cancer Prevention Trial (PCPT). After natural logarithm-transformation of hsCRP, analysis of variance was used to estimate the within- and between-individual variances from which the intra-class correlation coefficient (ICC) was calculated. RESULTS: The observed RR due to an ICC < 1 was calculated by e((ln true RR*ICC)) for a range of true RRs. The 4-year ICC was 0.66. Measuring hsCRP once and assuming no other error, if the true RRs were 1.50, 2.00, and 3.00 when comparing high with low concentration, then the observed RRs would be 1.31, 1.58, and 2.06, respectively. CONCLUSION: Investigators planning to measure hsCRP only once should design adequately sized studies to preserve inferences for hypothesized modest to moderate RRs. |
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Authors:
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Elizabeth A Platz; Siobhan Sutcliffe; Angelo M De Marzo; Charles G Drake; Nader Rifai; Ann W Hsing; Ashraful Hoque; Marian L Neuhouser; Phyllis J Goodman; Alan R Kristal |
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Publication Detail:
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Type: Journal Article; Multicenter Study; Research Support, N.I.H., Extramural Date: 2010-02-05 |
Journal Detail:
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Title: Cancer causes & control : CCC Volume: 21 ISSN: 1573-7225 ISO Abbreviation: Cancer Causes Control Publication Date: 2010 Jun |
Date Detail:
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Created Date: 2010-05-14 Completed Date: 2010-08-20 Revised Date: 2013-05-31 |
Medline Journal Info:
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Nlm Unique ID: 9100846 Medline TA: Cancer Causes Control Country: Netherlands |
Other Details:
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Languages: eng Pagination: 847-51 Citation Subset: IM |
Affiliation:
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Department of Epidemiology, Johns Hopkins Bloomberg School of Public Health, 615 N. Wolfe St., Rm E6132, Baltimore, MD 21205, USA. eplatz@jhsph.edu |
Export Citation:
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APA/MLA Format Download EndNote Download BibTex |
| MeSH Terms | |
Descriptor/Qualifier:
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Aged C-Reactive Protein / diagnostic use, metabolism* Clinical Laboratory Techniques / adverse effects Epidemiologic Studies Humans Male Middle Aged Prospective Studies Research |
| Grant Support | |
ID/Acronym/Agency:
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CCOP2016//PHS HHS; P01 CA 108964/CA/NCI NIH HHS; P01 CA108964-01A1/CA/NCI NIH HHS; P01 CA108964-06/CA/NCI NIH HHS |
| Chemical | |
Reg. No./Substance:
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9007-41-4/C-Reactive Protein |
| Comments/Corrections | |
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine
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