Irregular Menstrual Cycles Bring Higher Risk of Diabetes
Nov. 20, 2001 -- Having an irregular or absent menstrual cycle is one of the dominant characteristics of polycystic ovary syndrome, a hormonal disorder that still is somewhat a mystery today and affects as many as one in 10 women. The condition is known to be associated with reduced fertility, but the evidence is mounting that it also increases a woman's risk of developing diabetes.
Now a newly published study offers the best evidence to date that menstrual cycle irregularity is directly linked to type 2 diabetes risk. Researchers at Boston's Brigham and Women's Hospital and the Harvard School of Medicine followed more than 100,000 women participating in the Nurses Health Study II, the largest ongoing study of risk factors for chronic diseases in women.
Young women with cycles of more than 40 days or cycles that were too irregular to estimate were found to be twice as likely to develop diabetes as those with normal cycles. The increased risk was seen even when the researchers accounted for obesity, which is a common characteristic of polycystic ovary syndrome (PCOS) and a well-established risk factor for diabetes. The findings were reported Nov. 21 in The Journal of the American Medical Association.
"Women and their doctors need to be aware that irregular menstrual cycles could have broader ramifications than those that they normally think of," lead author Caren G. Solomon, MD, tells WebMD. "We know that women with PCOS have higher rates of diabetes ..., independent of their weight. We also know from other data that the majority of women with irregular cycles probably have PCOS."
The findings suggest that maintaining a healthy weight may be even more important for women who have been diagnosed with PCOS or have irregular cycles. Obesity, specifically excess weight around the abdomen, is a characteristic feature of PCOS. Having an 'apple shape' body type is also a specific risk factor for diabetes and heart disease.
A soon-to-be published national study suggests that those at high risk for diabetes can cut that risk in half by losing a modest amount of weight and exercising regularly as little as 30 minutes a day. Researchers found that moderate weight loss and exercise were twice as effective as taking medication at reducing risk.
"We know that no matter what your risk factors are, maintaining a healthy weight and exercising are key to reducing your risk of this disease," diabetes researcher Edward E. Horton, MD, tells WebMD. Horton, is director of clinical research at Boston's Joslin Diabetes Center and a professor at Harvard Medical School.
"No matter what your cycles are, we know that being overweight and being sedentary are risk factors for diabetes," Solomon adds. "But I think the important message here is that obesity clearly exacerbates the risk that is associated with an irregular cycle. Every woman should eat a healthy diet and get regular exercise, but this is group that may stand to benefit from that even more than others."