Breast cancer ribbonElevated levels of insulin in the blood may increase the possibility of breast cancer in postmenopausal women. Scientists at Albert Einstein College of Medicine of Yeshiva University seem to have found a link between raised insulin and increased chances of breast cancer risk.

In earlier times, obesity and diabetes were known to raise the risk of breast cancer in postmenopausal women. These two conditions include insulin resistance, which was noted to cause an increase in rotating levels of insulin. It was observed that, in animal models, insulin supported cell division and increased breast tumor growth. Experts at Einstein reasoned that relatively elevated insulin levels may contribute to breast cancer risk in women.

“Up to now, only a few studies have directly investigated whether insulin levels are associated with breast cancer risk, and those studies have yielded conflicting results. Those other studies were based on just a single baseline measurement of insulin, while 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,” says lead author and Ph.D., senior epidemiologist in the department of epidemiology and population health at Einstein, Geoffrey Kabat.

For the purpose of this study, Dr. Kabat and his colleagues seem to have examined information on nearly 5,450 women, who were enrolled in the Women’s Health Initiative. This was a large multicenter study which investigated the influence of a number of reasons that affect women’s health.

Many women were involved in the clinical trail part of the study. At the beginning of the study, they gave fasting blood samples and then again at intervals of one, three and six years. Whereas rest of the women participated in a separate ‘observational’ part of the study. They provided fasting blood samples at the beginning and in the third year. Over a period of eight years, approximately 190 cases of breast cancer were recognized among all these women.

Dr. Kabat and colleagues’ analysis revealed a strong connection between elevated insulin levels and increased risk for breast cancer. The participants were classified into three groups based on their insulin levels. Experts found that women in the upper third for insulin level had double the chances of developing breast cancer in contrast to women in bottom third for insulin level.

Women who had not received treatment i.e., the placebo participants or those who were in the observational part showed a stronger connection between insulin level and breast cancer risk. In addition, women in the upper third for insulin level had an additional three-fold elevated risk for breast cancer as compared to those in the bottom third. The connection between insulin level and breast cancer appeared to be the strongest in lean women while weakest among obese women.

“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,” says Dr. Kabat. However, this finding was an opening as the number of lean women was less.

Though these results need affirmation from other studies, Dr. Kabat was of the opinion that by maintaining a healthy weight and engaging in regular physical exercise may assist in reducing insulin levels. These were believed to be the present recommendations for reducing breast cancer risk in postmenopausal women.

This analysis has been published in the online version of the International Journal of Cancer. The paper is named as, ‘Repeated measures of serum glucose and insulin in relation to postmenopausal breast cancer’.