Body Mass Index gain throughout adulthood may increase risk of postmenopausal breast cancer

April 20, 2010

Reported mid-life increase in body mass index (BMI) may lead to substantially higher risk of postmenopausal breast cancer, according to results of a prospective cohort study presented at the American Association for Cancer Research 101st Annual Meeting 2010, held here April 17-21.

In previous studies, excess weight has been linked with increased risk of postmenopausal breast cancer. Scientists have speculated that in , produced in adipose tissue, or body fat, may promote breast cell proliferation. Relatively few studies have looked specifically at increase in BMI and its timing in relation to postmenopausal breast cancer risk, which this study investigated.

The researchers analyzed information from 72,007 women in the Prostate, Lung, Colorectal and Ovarian Trial cohort, who were 55 to 74 years old at study entry. The analysis included 3,677 cases of postmenopausal breast cancer, which makes this one of the larger studies of its kind, according to the researchers.

The researchers observed the strongest associations among women who had never used menopausal hormone therapy; results were shown only for this group of women.

"Compared with women who maintained approximately the same BMI, those who had an increase of 5 kg/m2 or more between age 20 and study entry had a nearly twofold increased risk of breast cancer," said Laura Sue, M.P.H., a cancer research fellow at the National Cancer Institute (NCI).

Results showed that nearly 57 percent of the study population's BMI increased 5 kg/m2 or more between age 20 and study entry. A BMI increase of 5 kg/m2 is equivalent to a woman of average height, 5'4", gaining approximately 30 pounds.

Women who reported a BMI increase of 5 kg/m2 or more between age 20 and 50 were at an 88 percent increased risk of developing postmenopausal breast cancer, compared with women who reported a stable BMI. For women who reported a BMI increase of 5 kg/m2 or more between age 50 and study entry, risk increased 56 percent, compared with women who maintained BMI. BMI gain both before and after age 50 independently contribute to increased risk of postmenopausal .

Explore further: Overweight and obesity cause 6,000 cancers a year in UK women

Related Stories

Strong link between obesity and colorectal cancer

December 14, 2007

A clear, direct link between obesity and colorectal cancer, the second most common form of cancer in Australia with more than 12,000 new cases each year, has been shown in a new analysis by The George Institute for International ...

Estrogen therapy increases benign breast disease risk

April 8, 2008

Women who took conjugated equine estrogen, a commonly prescribed form of estrogen, had more than twice the risk of developing specific types of benign breast disease as women who took a placebo, according to a randomized ...

Obesity linked with poorer breast cancer outcomes

December 10, 2009

Breast cancer patients with a high body mass index (BMI) have a poorer cancer prognosis later in life. Specifically, their treatment effect does not last as long and their risk of death increases.

Recommended for you

How the finch changes its tune

August 3, 2015

Like top musicians, songbirds train from a young age to weed out errors and trim variability from their songs, ultimately becoming consistent and reliable performers. But as with human musicians, even the best are not machines. ...

Machine Translates Thoughts into Speech in Real Time

December 21, 2009

( -- By implanting an electrode into the brain of a person with locked-in syndrome, scientists have demonstrated how to wirelessly transmit neural signals to a speech synthesizer. The "thought-to-speech" process ...


Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.