Risk of invasive breast cancer was found to be more in postmenopausal women who were overweight or obese than women having normal weight.

Study researchers have used data from the Women's Health Initiative clinical trials to reach at the above mentioned conclusion. Study researcher Marian L. Neuhouser from the Fred Hutchison Cancer Research Center said they have studied the link between being overweight or obese and risk of postmenopausal invasive breast cancer.

The study is based on the observation of 67,142 postmenopausal women enrolled from 1993 to 1998 and they were followed for 13 years. The researchers said 3,388 invasive breast cancers were involved.

The researchers said, "Obesity is associated with a dose-response increased postmenopausal breast cancer risk, particularly for estrogen receptor- and progesterone receptor-positive disease, but risk does not vary by HT use or race/ethnicity".

The study findings encourage the need of carrying out clinical trials so that the role of obesity prevention can be found out.

Important Findings of the study are:

"Having BMI of 35 and above was linked with heightened risk of estrogen and progesterone receptor-positive breast cancer.

"In comparison to normal weight, women who were obese or overweight were at increased risk of having the cancer.

"The risk of cancer was the most for women having BMI greater than 35. These women had 58% increased risk of having the cancer.

"No benefit in risk decline even when overweight or obese women reduced weight.

Experts said that overweight and obesity is an increasing global challenge. There is a need to maintain weight.