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- Statistical methods for analysis of combined biomarker data from multiple nested case-control studies
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Statistical methods for analysis of combined biomarker data from multiple nested case-control studies
Stat Methods Med Res. 2021 Jul 7;9622802211025992. doi: 10.1177/09622802211025992
Chao Cheng 1, Abigail Sloan 2, Molin Wang 2 3 4VitaminDWikiTests for Vitamin D contains the following overview/opinion
- Fact: Many countries no longer pay for more than 1 (some not pay for even a single Vit D test)
They feel that Vit D testing is not needed except for a few conditions (Rickets, etc) Japan is an exception - Fact: Vit D tests are not very accurate
The best lab tests have accuracies and repeatabilities of +-5 ng
Low cost vitamin D Blood Tests - both in lab and at home
Many lab tests have accuracies and repeatabilities of +- 10 ng - or worse
Vitamin D deficiency of a group - 15% to 48% - Fact: Low-cost office/home Vit D tests are available around the world (not US as of 2018)
Low-cost 35 ng Y/N test by Nanospeed
Low-cost Vitamin D testers (two yes-no tests for 42 dollars) - 2023 Nanospeed
Quick, free, self test for deficiency - Fact: 3 major Vit D gene problems are not noticed by Vit D tests
~ 20% of people have poor Vit D genes
Hint that Vit D not getting to cells: Vit D related diseases run in your family
Another hint - you have one of the 40 diseases which are 2X more likely if have poor genes - Fact: A Vit D test will rarely (<1 in 1000) indicate that you are getting too much
- Opinion: If only getting a single test, wait till after supplementing with Vit D
3 months after starting a maintenance dose or 4 weeks after a loading dose
- 4 popular vitamin D testers gave very different results (no surprise) – June 2021
- Vitamin D testing accuracies, including dried blood spot – Jan 2020
- Problems with Vitamin D Testing – chapter – Aug 2019
- Vitamin D deficiency of a group - 15 pcnt to 48 pcnt (depends on tester used) - Nov 2017
By combining data across multiple studies, researchers increase sample size, statistical power, and precision for pooled analyses of biomarker-disease associations. However, researchers must adjust for between-study variability in biomarker measurements. Previous research often treats the biomarker measurements from a reference laboratory as a gold standard, even though those measurements are certainly not equal to their true values. This paper addresses measurement error and bias arising from both the reference and study-specific laboratories. We develop two calibration methods, the exact calibration method and approximate calibration method, for pooling biomarker data drawn from nested or matched case-control studies, where the calibration subset is obtained by randomly selecting controls from each contributing study. Simulation studies are conducted to evaluate the empirical performance of the proposed methods. We apply the proposed methods to a pooling project of nested case-control studies to evaluate the association between circulating 25-hydroxyvitamin D (25(OH)D) and colorectal cancer risk.
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How to compare Vitamin D measurements from multiple studies – July 2021Printer Friendly Follow this page for updates770 visitors, last modified 27 Nov, 2022, This page is in the following categories (# of items in each category) - Fact: Many countries no longer pay for more than 1 (some not pay for even a single Vit D test)
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