Obesity linked to breast cancer

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By Jimmy Downs

Saturday Sept 29, 2012 (foodconsumer.org) -- Women who live with obesity are at higher risk for breast cancer compared with those who have a normal body mass index (BMI), according to a new study in the International Journal of Cancer.

Kami K. White at University of Hawaii Cancer Center in Honolulu, HI and colleagues conducted the study and found Native Hawaiian women who had a body mass index 30 kg/m2 or greater or obesity were 82 percent more likely to develop breast cancer compared to those who had a BMI of 20 to 24.9 kg/m2.  

Among Japanese women in Hawaii and California, those who had a BMI of 30 kg/m2 or greater or obesity were at 59 percent increased risk of breast cancer, compared to those who had a BMI of 20 to 24.9 kg/m2.

White et al. found the associations after analysing data from 82,971 White, African, native Hawaiian, Japanese and Latina women aged 45 to 75 years and residing in Hawaii and California, who were recruited for the Multiethnic Cohort study between 1993 and 1996.  Of participants, 3,030 were diagnosed with invasive breast cancer.

Overall, they found body mass index, height, weight and adulthood weight gain were all correlated with a significantly higher risk  and the associations were found to vary from one ethnic group to another for all the factors with the exception of height.

The impact of BMI on the risk of breast cancer was influenced by the status of the hormone replacement therapy use. BMI had a higher impact on the risk in non- or former users of hormone therapy compared to the current users.  Also advanced breast cancer was more significantly associated with BMI, compared to localized breast cancer.

When both BMI and weight gain were analysed together, adult weight gain had a more significantly positive impact on the risk of breast cancer than BMI, suggesting it is important to maintain a healthy weight throughout adulthood for the prevention of breast cancer in postmenopausal women.

Breast cancer is preventable in many cases.  But obesity may not be the biggest risk for the disease.  According to an authoritative organization, two major risk factors for breast cancer, which are absolutely certain, are medical radiation used in medical diagnostics and hormone therapy.  Some experts claim that preventing vitamin D deficiency may help prevent 75 percent of breast cancer cases.

Previous studies have associated green tea drinking, high intake of omega-3 fatty acids found in fish oil, soy protein, and choline and betaine supplements all may reduce the risk of breast cancer.

About 230,000 women are expected to be diagnosed with breast cancer in 2012 in the United States and the disease and the complications from the disease and treatment kill nearly 40,000 in 2012  in the country, according to the National Cancer Institute.

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