Women with larger breast size have a higher incidence of developing breast cancer than women with small or average sized breasts, a new study from Australia reported.

In the present study, conducted by researchers at The University of Western Australia and BreastScreen WA, researchers collected data from more than 700,000 women in Australia. All women were more than 40 years old and 55,000 women in the study group had large breasts.

Researchers described large breast size that required larger mammogram film cassette of 24 x 30cm whereas standard mammogram films require 18 x 24cm.

Women with larger breasts have more tissue available for the cancer to grow and also because larger breast are tied to higher estrogen levels.

Earlier studies have shown that breast morphology like density increase risk of breast cancer but a cause and effect link between breast size and cancer has not been established yet.

Medical Daily had earlier reported on a study that said that genetic factors associated with larger breasts were co-related to those that cause breast cancer. The average bra size in the U.S. has gone up from 34B to 36C in just one generation.

Experts say that multiple factors are associated with a woman developing breast cancer like age, menopause, ethnicity, obesity, lifestyle factors etc. 

"This study confirms the appropriateness of mammographic screening for women with large breasts," the authors of the study wrote in the journal.

Yearly mammography is recommended for all women after age 40 but recent studies have shown that these once-a-year tests have caused an over diagnosis of the cancer in the U.S.  Experts say that these diagnoses cause additional stress, anxiety and medical treatment.

The present study was published in the journal The Breast.