Coffee consumption may reduce breast cancer risk .OT

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Coffee consumption may reduce breast cancer risk

NEW YORK (Reuters Health) - High levels of coffee consumption may

reduce the risk of breast cancer among women with BRCA1 gene

mutations, according to a multicenter team of investigators.

The results of some animal studies have suggested that coffee

consumption may increase the risk of breast cancer, while others have

found that coffee may suppress breast tumors, Dr. A. Narod, of

the University of Toronto, Ontario, and colleagues report.

In a matched case-control study, the researchers examined the

association between coffee consumption and the risk of breast cancer

among 1690 high-risk women with BRCA1 or BRCA2 mutations. Included in

the study were women from 40 clinical centers in four countries. A

self-administered questionnaire was used to assess the average

lifetime coffee consumption, and conditional logistic regression

analysis was used to estimate odds ratios.

The odds ratios for breast cancer among BRCA mutation carriers who

drank no coffee, 1 to 3 cups, 4 to 5 cups, or 6 or more cups of

coffee were 1.00, 0.90, 0.75, and 0.31, respectively, (p for trend =

0.02) after adjustment for potential confounders, according to the

report in the January issue of the International Journal of Cancer.

When the investigators stratified the women by mutation status, they

found a significant protective trend for increasing caffeinated

coffee consumption among women with a BRCA1 mutation (p = 0.009). No

such trend was found for carriers of a BRCA2 mutation.

The investigators note that coffee is an important source of

phytoestrogens, which may have chemoprotective effects.

" The mechanism by which phytoestrogens may beneficially influence the

risk of breast cancer has predominantly been attributed to their

structural similarity to endogenous estrogens and their ability to

bind to estrogen receptors, " Dr. Narod and colleagues explain.

" Coffee consumption has been associated with a higher level of

circulating sex hormone binding globulin, which decreases the level

of bioavailable estrogen. "

" It will be of importance to confirm this association in other

populations and, if confirmed, to explore the biologic basis for this

observation, " the researchers conclude.

Int J Cancer 2006;118:103-107.