Fat raises breast cancer risk
2007-03-22 13:49
New York - A large study of middle-age
women with a wide range of fat in their diet shows that eating
a high-fat diet raises the risk of developing invasive breast
cancer.
The findings, reported in the Journal of the National
Cancer Institute, stem from the National Institutes of
Health-AARP Diet and Health Study, in which 188 736
postmenopausal women reported detailed information on their
diet in the mid-1990s.
During an average follow-up of 4.4 years, 3501 women
developed breast cancer.
Based on responses to a 124-item "food frequency"
questionnaire, researchers found that women who got 40%
of their calories from fat had about a 15% increased
risk of developing breast cancer compared with women got 20%
of their calories from fat.
Using a more precise 24-hour dietary recall questionnaire,
"we found a 32% increased risk of breast cancer" among
women with a high level of fats in their diet, noted study chief Dr.
Anne C. M. Thiebaut from the National Cancer Institute in
Bethesda, Maryland.
Hormone replacement therapy
The increased risk of breast cancer associated with a
high-fat diet was seen for all types of fat (saturated,
monounsaturated and polyunsaturated) and seemed to be confined
to women who were not using hormone replacement therapy at the
start of the study.
The suggestion that hormone therapy mediates the
association between dietary fat intake and risk of breast
cancer should be studied further, the authors suggest.
Thiebaut noted that "other studies have also found these
associations; the higher the fat intake, the higher your risk
for breast cancer". Nonetheless, there is ongoing debate about
the association between dietary fat and the risk of breast
cancer, she noted.
In a commentary on the study, two researchers from Harvard
School of Public Health in Boston think that focusing on
controlling body fat, rather than fat intake, would be more
effective in preventing breast cancer.
The "modest associations" that have been observed between
high-fat diets and increased breast cancer risk "stand in sharp
contrast to the robust evidence for a strong link between (body
fat) and the risk of postmenopausal breast cancer," write Drs.
Stephanie Smith-Warner and Meir Stampfer.
SOURCE: Journal of the National Cancer Institute, March 21,
2007.