CHAPEL HILL, N.C. -- We know obesity is often a risk factor for breast cancer, but a new study found that younger women with higher body fat were actually less likely to develop breast cancer prior to menopause.

Spectrum News anchor Caroline Blair wanted to know how this was possible, and sat down with UNC Lineberger Comprehensive Cancer Center researcher Dr. Hazel Nichols for a look at the international study.

Researchers from around the world, through 19 different studies, polled a group of 758,592 women under the age of 55 for this research. And their analysis links higher BMI or body mass index, to lower breast cancer risk for pre-menopausal women. But Nichols says there was no threshold where having a higher body mass index was linked to have a lower risk of cancer.

We know breast cancer is more common in older women, with the median age diagnosed at 62 years old in the U.S. And while obesity is linked to higher chances of breast cancer in post-menopausal women, they found that wasn’t the case for those in the younger category. Nichols says this is not an excuse however to gain weight, because obesity is linked to a number of other health issues. But she says that there are multiple factors that could be contributing to this link.

Nichols says that estrogen can be a driver in breast cancer, but estrogen levels change at different points in our lives. She says before menopause, our main source of estrogen comes from women’s ovaries. this means estrogen produced by fat tissue may actually reduce the amount of estrogen our body produces prior to menopause. But the exact opposite happens after menopause. Nichols says women with higher body fat tend to have higher estrogen levels thus increasing their chance for breast cancer.

Nichols and other researchers at UNC say that’s why understanding your risk factors for cancer is so incredibly important. She says the team will now continue to look at the research to determine how to better serve younger women who are at risk.

For more details on UNC’s Lineberger Comprehensive Cancer Center, visit their website.