Postmenopausal women with elevated insulin levels may face greater risk of developing breast cancer, a new study has found.

U.S. researchers drew the conclusion after examining data on 5,450 women who took part in the Women's Health Initiative, a large study that looked at how various factors influence women's health, according to the study published online on Thursday in the International Journal of Cancer.

The study was conducted by researchers at Albert Einstein College of Medicine of Yeshiva University in New York City.

The researchers found a strong association between elevated insulin levels in the blood and increased risk of breast cancer.

Women with insulin levels in the highest third were twice as likely to develop breast cancer as women in the bottom third, according to the study.

The team also discovered that the link between elevated insulin levels and breast cancer was stronger for thin women than for obese women, who tend to have higher insulin levels.

"Up to now, only a few studies have directly investigated whether insulin levels are associated with breast cancer risk," said Geoffrey Kabat, the lead author and senior epidemiologist in the department of epidemiology and population health at Einstein.

"Our study involved analyzing repeated measurements of insulin taken over several years -- which provides a more accurate picture of the possible association between insulin levels and breast cancer risk," said Kabat.

"This finding is potentially important because it indicates that, in postmenopausal women, insulin may be a risk factor for breast cancer that is independent of obesity," Kabat said.

Kabat recommended that postmenopausal women try to keep insulin at normal levels through weight loss, regular exercise and other methods.

(Xinhua News Agency July 24, 2009)