Insulin resistance syndrome, also known as metabolic syndrome, has long been known to increase the risk of diabetes and heart disease. However, a new study that was released in the July 2009 issue of Cancer Epidemiology, Biomarkers and Prevention, also presents convincing evidence for a link between metabolic syndrome and postmenopausal breast cancer.
While this might not sound like good news, in fact it is -- or rather, it could be.
Insulin Resistance, or Metabolic Syndrome
Insulin resistance syndrome is usually associated with poor diet and lack of exercise. It is considered a preventable condition and can even at times be reversible through adapting a healthy lifestyle. This new study suggests that with proper lifestyle management, millions of women can decrease their likelihood of contracting postmenopausal breast cancer.
It has long been known that metabolic syndrome most commonly occurs in sedentary people who are overweight, eat junk food and make poor nutrition choices in general. Commonly recognizable symptoms are abdominal obesity, hypertension, and high blood sugar, as well as high blood pressure.
An alarmingly high number of Americans now suffer from metabolic syndrome. Recently, the National Heart, Lung and Blood Institute noted that nearly 25 percent of all Americans have the condition. The condition is growing at such an fast rate due to the increase in obesity, which is well on its way to overtaking smoking as the leading risk factor for heart disease.
Metabolic Syndrome and Breast Cancer
In this latest study, Dr. Geoffrey Kabat of Albert Einstein College of Medicine in New York, has determined that a detection of insulin resistance syndrome 3 to 5 years before a breast cancer diagnosis was associated with an increased risk of total and invasive breast cancer.
Dr. Kabat's study, which was the first to explore a possible link between insulin resistance and breast cancer, used existing data collected on 4,888 postmenopausal women from the Women's Health Initiative. That particular large group study was created to explore major causes of chronic diseases in women.
All the women in the Kabat study were free of diabetes at baseline. With a median follow-up of eight years time, Dr. Kabat and his colleagues recorded 165 incidents of breast cancer, of which 131 were invasive and 34 were in situ.
Initially, baseline presence of metabolic syndrome was not found to be associated with an increased cancer risk. However it was the analysis of repeated measurements over time that lead to the identification of the condition occurring 3 to 5 years prior to the breast cancer diagnoses, which was ultimately associated with the elevated risk toward total and invasive breast cancer.
The researchers further reported that higher blood glucose levels, triglycerides and diastolic blood pressure were individually linked to a greater cancer risk. Increased diastolic blood pressure alone raised the risk of breast cancer 2.4 times.
As the researchers stated it, "The metabolic syndrome could influence the risk of breast cancer through changes in a number of interrelated hormonal pathways, including those involving insulin, estrogen, cytokines, and growth factors."
Tim Byers, a researcher and associate dean at the Colorado School of Public Health and interim director of the University of Colorado Cancer Center, suggests that these findings can help to explain why being overweight is a known risk factor for causing postmenopausal breast cancer.
"We have assumed that the relationship between weight and breast cancer risk is due to increased circulating estrogens among postmenopausal women who are overweight or obese," he said in a statement released to the media. "An alternative explanation is explored here: that some other aspect of the metabolic syndrome might be involved, such as growth-stimulating effects of insulin, or insulin-like growth factors."
Dr. Byers has also suggested that further research may be necessary to determine specific ways in which the metabolism of the female hormone estrogen is linked to the metabolic syndrome. "Though estrogens are produced in adipose (fat) tissues, just how these are metabolized in various subgroups of women needs better study. In addition, the hyper-inflammatory state of obesity and the metabolic syndrome need to be better described relative to cancer risk," he said.
Dr. Kabat has agreed that ultimately more research is necessary. “Much more work is needed to understand the role of these metabolic factors and their interplay with better established breast cancer risk factors, such as reproductive and hormonal factors," he noted.
And Now, the Good News
There is a light at the end of the tunnel. Women who are worried about breast cancer and are already exhibiting symptoms of insulin resistance syndrome now have a clear-cut reason to take charge and make changes in their lives.
Studies have long supported the idea that metabolic syndrome is a preventable and in many cases reversible condition. Such simple steps as smoking cessation, exercise and a reduced calorie diet may go a long way towards stemming off the onset of the condition in the first place.
Other measures, such as adopting a Mediterranean style diet, with abundant plant foods, fresh fruit as a typical desert, olive oil as the primary source of fat and dairy, fish and poultry consumed in moderate portions, have been known to reverse the onset of insulin resistance syndrome. While a major lifestyle shift may not be for everyone, even the simple measures of taking 30 minutes of exercise a day and improving one's diet slightly will achieve some measure of good.
With this new evidence suggesting the link between insulin resistance syndrome and breast cancer, we could be at the doorway of a golden opportunity. In past studies, the conclusion has been made that measures such as those suggested here are effective only in a small minority of people, primarily due to a failure to comply with the lifestyle and diet change.
But with such strong past evidence linking insulin resistance syndrome to heart disease and diabetes now being bolstered by new evidence tying it to breast cancer, one would hope that the message will finally be heard and taken seriously.