A new study that included 287,000 women and noticed their mammogram habits, says that increasing weight can boost the risk of developing breast cancer in older women.

Dr. Karla Kerlikowske, who led the study, says: “There are higher levels of circulating estrogens in women have increased body weight that leads to promote tumor growth in them.”

In another study, Kerlikowske and team have examined postmenopausal women with hormone replacement therapy (HRT) and they have found higher risk of breast cancer in them.

In this new study, they looked at postmenopausal women who didn’t receive HRT. The study is to be published in the Journal of the National Cancer Institute, Dec.3 issue.

Some researchers seem to believe that in obese women, the higher risk of the disease is because of their inadequate screening, as their tumors are quite difficult to find out in mammography.

But in the current study, these risk factors have been excluded. “In our study, we also examined how many times they were screened and how well the detection of cancer was and we still found a higher risk in them,” Kelikowske added.

In this study, data from mammograms of more than 287,000 women who had routine mammograms, the researchers concluded that it wasn’t hard to detect tumors in overweight women.