Dear Owen,
Thank you for your email, and your interest in our study published last week. There are too many differences between the 2 studies you mention to make any direct comparisons (other than both studies consisting of male health professionals).
The Rimm et al study (a cohort study, the Health Professionals Follow-up Study) was conducted among male health professionals aged 40 to 75 years and initially free of coronary heart disease at baseline, and with 3-4 years follow-up. Their endpoint was different - coronary heart disease (MI, CHD death) plus percutaneous coronary interventions.
The Physicians' Health Study II participants were considerably older at baseline (aged 50+ years, and mean age 63). Rates of CHD and/or CVD increase exponentially with age. In addition, some PHS II subjects had baseline cardiovascular disease, further increasing our overall rates of major cardiovascular events. And follow-up in PHS II was much longer (mean of 8 years), which allowed these older participants to develop more events over time. And finally, our primary primary endpoint was different - a combined endpoint of MI, stroke, and CVD death.
So .... the fact that our rates of CVD were higher, even though direct comparisions are not really valid here, is not very surprising....
I hope this clarifies things for you.
Kind regards,
Howard
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Howard D. Sesso, ScD, MPH
Assistant Professor of Medicine
Division of Preventive Medicine
Brigham and Women's Hospital
900 Commonwealth Avenue East - 3rd Floor
Boston, MA 02215
(w) 617-732-8837
(f) 617-731-3843
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From: orfonorow@aol.com [mailto:orfonorow@aol.com]
Sent: Wednesday, November 12, 2008 5:53 PM
To: hsesso@hsph.harvard.edu
Cc: vitamincfoundation@att.net
Subject: question on Vitamin C/E Study
Dear Dr. Sesso,
Thank you for your study as published in JAMA Nov 9.
I found an earlier study by Rimm,
http://content.nejm.org/cgi/content/abs ... 28/20/1450
and I was wondering what your thoughts were on the difference between the rates
of CVD events in your study and the earlier 1993 study. The Rimm study was of 4 years,
39910 male physicians and recorded 667 CVD events.
Your population was about 1/3, but the rate of CVD (on a yearly basis) seems to be at least 3 times higher.
Thank you for your response.
Owen Fonorow
Vitamin C Foundation--------------------------------------------------------------------------------
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