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Krebs
Vorbeugen mit B-Vitaminen?
An der Women's Antioxidant and Folic Acid Cardiovascular Studie
nahmen in de USA 5.442 US weibliche Patienten teil, die
ein hohes Herz-Kreislaufrisiko hatten. Die Versuchsteilnehmerinnen
erhielten über 7 Jahre entweder ein Scheinmedikament (Placebo)
oder eine Kombination von täglich 2.5 mg Folsäure, 50 mg Vitamin
B6 und
1 mg Vitamin B12. Viele Experten gingen bisher davon aus,
dass die untersuchten B-Vitamine eine wichtige Rolle bei der Entstehung,
bzw. Vorbeugung von Krebs spielen.
Die
im JAMA (Journal of the American Medical Association) publizierten
Ergebnisse der Untersuchung widerlegten die optimistische Annahme,
dass sich bei Frauen durch die regelmäßige Einnahme der drei B-Vitamine
bestimmte Krebserkrankungen verhindern lassen. Es zeigte
sich, dass in der Therapie- bzw. der Placebo-Gruppe nahezu gleich
viele Fälle von invasivem Krebs und Brustkrebs auftraten. Auch
die Zahl der Krebstodesfälle war nahezu identisch.


Die
vollständige englischsprachige Version dieser Studie
finden Sie
hier
Effect of Combined Folic Acid, Vitamin B6, and Vitamin B12 on
Cancer Risk in Women
A Randomized Trial
Shumin M. Zhang, MD, ScD; Nancy R. Cook, ScD; Christine M. Albert,
MD, MPH; J. Michael Gaziano, MD, MPH; Julie E. Buring, ScD; JoAnn
E. Manson, MD, DrPH
JAMA. 2008;300(17):2012-2021.
Context
Folate, vitamin B6, and vitamin B12 are thought to play an important
role in cancer prevention.
Objective
To evaluate the effect of combined folic acid, vitamin B6,
and vitamin B12 treatment on cancer risk in women at high risk
for cardiovascular disease.
Design, Setting, and Participants
In the Women's Antioxidant and Folic Acid Cardiovascular Study,
5.442 US female health professionals aged 42 years or older, with
preexisting cardiovascular disease or 3 or more coronary risk
factors, were randomly assigned to receive either a daily combination
of folic acid, vitamin B6, and vitamin B12 or a matching placebo.
They were treated for 7.3 years from April 1998 through
July 31, 2005.
Intervention
Daily supplementation of a combination of 2.5 mg of folic
acid, 50 mg of vitamin B6, and 1 mg of vitamin B12 (n = 2721)
or placebo (n = 2721).
Main Outcome Measures
Confirmed newly diagnosed total invasive cancer or breast cancer.
Results
A total of 379 women developed invasive cancer (187
in the active treatment group and 192 in the placebo group). Compared
with placebo, women receiving the active treatment had similar
risk of developing total invasive cancer (101.1/10 000 person-years
for the active treatment group vs 104.3/10 000 person-years for
placebo group; hazard ratio [HR], 0.97; 95% confidence interval
[CI], 0.79-1.18; P = .75), breast cancer (37.8/10 000 person-years
vs 45.6/10 000 person-years, respectively; HR, 0.83; 95% CI, 0.60-1.14;
P = .24), or any cancer death (24.6/10 000 person-years
vs 30.1/10 000 person-years, respectively; HR, 0.82; 95% CI, 0.56-1.21;
P = .32).
Conclusion Combined folic acid, vitamin
B6, and vitamin B12 treatment had no significant effect on overall
risk of total invasive cancer or breast cancer among women during
the folic acid fortification era.
Trial Registration clinicaltrials.gov Identifier: NCT00000541
Author Affiliations: Divisions of Preventive Medicine (Drs Zhang,
Cook, Albert, Gaziano, Buring, and Manson) and Aging (Drs Gaziano
and Buring), Department of Medicine, Brigham and Women's Hospital
and Harvard Medical School; Department of Epidemiology, Harvard
School of Public Health (Drs Cook, Buring, and Manson); Veterans
Affairs Boston Healthcare System (Dr Gaziano); and Department
of Ambulatory Care and Prevention, Harvard Medical School (Dr
Buring), Boston, Massachusetts.
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