Women who want to have an idea of their risks for developing breast cancer may want to check out their skirt sizes over the years. Findings of a University College London (UCL) study reveal that women whose skirt size barely changed since they were in their 20's have the best odds of avoiding breast cancer.

For the new study published in the journal BMJ Open on Sept. 24, Usha Menon from the Department of Women's Cancer of the UCL Institute for Women's Health in the U.K, and colleagues involved over 90,000 post-menopausal women who were at least 50 years old, 1,090 of whom developed breast cancer during the three-year follow-up period.

The researchers found that women whose dress size increased by one unit every ten years from when they were 25 years old to when they reach post-menopausal age, had 33 percent increased risks for breast cancer. Women whose waistline increased by two dress sizes in one decade, on the other hand, were associated with 77 percent increased risk for the condition regardless of their BMI.

"CSS is associated with BC risk independent of BMI. A unit increase in UK SS (eg, 12-14) every 10-years between 25 and postmenopausal-age is associated with postmenopausal BC risk by 33 percent," the researchers reported.

Although the researchers said that the study does not prove that increased waistline could lead to increased risks for developing breast cancer as there may have been changes in the sizing over the years, and the study relied on the participants recalling their skirt size when they were much younger, an expanding waistline is known to be associated with other forms of cancer include those that affect the ovaries, pancreas and the lining of the womb.

"Although the exact mechanism of these relationships need to be better understood, there is a suggestion that body fat around the waist is more metabolically active than adipose tissue elsewhere," Menon said adding that extra fat is known to increase the level of estrogen, the female hormone that fuels breast cancer cells.

The researchers also said that obesity, midriff fat in particular, is considered a significant risk factor for the development of breast cancer and the study has provided an easy measure for monitoring weight gain over time.

"This study highlights an easy way to monitor your weight gain over time," Simon Vincent, from the Breakthrough Breast Cancer said. "Women are more likely to remember their skirt size when they were younger than their BMI."