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"The results from this study suggest that weight loss in early adult life (age
18 to 30) protects against early onset BRCA-associated breast cancers," write
Steven Narod, MD, PhD, and colleagues in Breast Cancer Research .
"Weight gain should also be avoided, particularly among BRCA1 mutation carriers
who elect to have at least two [full-term] pregnancies," they continue.
Narod is a professor in the University of Toronto's public health sciences
department. He also directs the Familial Breast Cancer Research Unit at the
university's Centre for Research in Women's Health.
About the Study
More than 2,000 women from five countries participated. All had BRCA1 or BRCA2
gene mutations. Those with breast cancer were compared with women of similar
backgrounds without the disease.
The women filled out questionnaires about their weight at age 18, 30, and 40.
Self-reports of weight from past years aren't always accurate.
Some of the women reported fairly stable weight over the years. Others reported
losing or gaining more than 10 pounds.
Key Findings
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Breast cancer risk was 65% lower in women with the BRCA1 gene mutation who lost
10 pounds between ages 18 and 30, compared with those who didn't lose or gain
more than 10 pounds.
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Breast cancer risk was 44% higher in women with the BRCA1 gene mutation who had
two full-term pregnancies and gained more than 10 pounds between ages 8 and 30,
compared with women with relatively stable weight.
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Weight changes from age 30-40 didn't affect the risk of getting breast cancer
before or after menopause.
Age Mattered
"The period between age 18 and 30 years appears to be a critical one when weight
gain should be avoided in mutation carriers," write the researchers.
How much weight did the women lose?
Women with the BRCA1 gene mutation who lost more than 10 pounds from age 18-30
reported weighing an average of 142 pounds at age 18 and losing nearly 19
pounds, on average, by age 30.
The study doesn't say how the women lost weight. So, it's not known if they
exercised more, crash dieted, bounced up and down the scale, or permanently
upgraded their eating habits.
What About BRCA2?
In women with the BRCA2 gene mutation, weight loss in early adulthood brought
"modest" protection, but the benefit was mainly seen in women with the BRCA1
mutation.
That finding should be checked in the future, write the researchers. They note
that their study had a relatively small group of women with the BRCA2 gene
mutation, which might make it harder to detect patterns in those women.
If you are considering losing weight or have questions about your breast cancer
risk, consult your doctor.
A healthy lifestyle may also help reduce your risk of breast cancer. According
to the Susan G. Komen Foundation these may help:
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Be physically active.
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Maintain a normal weight.
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Reduce the amount of "bad" fats (saturated and trans fats) in your diet, and
eat foods that contain more "good" fats (polyunsaturated and monounsaturated
fats, like olive and canola oil). Certain types of fat may contribute to
increased risk of breast cancer and some can lower the risk.
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Take multivitamins with folic acid (often called folate on nutrition labels).
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Limit alcohol to less than a drink a day.
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Breastfeed instead of formula feed your infant if possible.
By Miranda Hitti
Reviewed By Kathleen Zelman, MPH, RD, July 25, 2007.
Medically updated July 25, 2007.
SOURCES: Kotsopoulos, J. Breast Cancer Research , Aug. 19,
2005; vol 7: pp R833-R843. News release, BioMed Central.
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