[Skip to Content]
Access to paid content on this site is currently suspended due to excessive activity being detected from your IP address 54.197.90.95. Please contact the publisher to request reinstatement.
[Skip to Content Landing]
Citations 0
Letters
April 8, 1998

Effect of Vitamins C and E on Vascular Reactivity

Author Affiliations
 

Margaret A.WinkerMD, Senior EditorIndividualAuthorPhil B.FontanarosaMD, Senior EditorIndividualAuthor

JAMA. 1998;279(14):1069-1070. doi:10-1001/pubs.JAMA-ISSN-0098-7484-279-14-jac80003

To the Editor.—Dr Plotnick and colleagues1 describe the use of duplex ultrasonography to determine changes in the brachial artery diameter associated with a high-fat meal. The authors claimed a significant alteration in arterial diameter, but although the differences may be statistically significant, they should not be construed as clinically significant. Based on the physics of ultrasound probes, the measurements reported by Plotnick et al are within 0.3 mm at best, presuming their machine is properly calibrated by the manufacturer. Their ultrasound machine will give caliper-derived data to within 0.1 mm. The authors report tabular data taken to the nearest 0.01 mm, based on a sample size of 20. The supposedly significant results they report are based on vasoreactivity measurements on the order of 0.2 mm. Can one really believe these data when the measured effect is less than the hidden "noise" of the machine?

First Page Preview View Large
First page PDF preview
First page PDF preview
×