Health Byte:

Weight gain and breast cancer

Research has already made a clear connection between obesity and breast cancer. But now a new study shows that weight gain over time also ups breast cancer risk.

Research has shown that being obese increases the risk of breast cancer, providing motivation for women to work diligently to drop unhealthy pounds and get fit. Now new studies show that there's more to the overweight-breast cancer connection than just being obese - even slow weight gain over a period of years increases a woman's breast cancer risk.

Studies show that post-menopausal obese women - based on their body mass index or BMI - have about double the breast cancer risk of women with a healthy body weight. Of course, when you factor in other risk factors like family history, taking hormone replacement therapy, leading a sedentary lifestyle, and consuming excessive amounts of alcohol, breast cancer risk rises even more.

As researchers delved deeper into the relationship between weight and breast cancer, they discovered something startling - that if you gain weight as you age, your breast cancer risk rises even if you are not obese.

What weight gain does

A study of 72,000 women who did not take any hormone therapy medication after menopause (itself a risk factor for breast cancer) found that women who had gained about 30 pounds in as many years were at twice the risk of developing breast cancer as women who had maintained their weight.

What's even more interesting is that these women didn't have to be obese to have an increased risk of breast cancer. The risk increased due to weight gain alone, even if the women never reached the definition of obesity, which is having a BMI of greater than 30.

Researchers don't yet fully understand how or why weight gain increases breast cancer risk, though it could be due to excess oestrogen production that could result from increased body fat.

- Everyday Health