Women who begin menopause before age 46 or after 55 have an increased risk of developing Type 2 diabetes, according to a new study.

The findings — published in the journal Menopause, the official journal of the North American Menopause Society — are based on an analysis of more than 124,000 women enrolled in the Women's Health Initiative, a large national trial aimed at preventing disease in postmenopausal women.

The study, led by Kaiser Permanente researcher Dr. Erin LeBlanc, found that women who had their final menstrual period before age 46 were 25 percent more likely to develop diabetes, compared to women who had their final period between ages 46 and 55. Women who had their final period after age 55 had a 12 percent increased risk of developing diabetes.

The average age of menopause is 51.

The researchers noted that after menopause, estrogen levels decline. These low levels of estrogen have been linked to increased body fat and appetite, decreased metabolism and high blood-sugar levels.

"Our study suggests the optimal window for menopause and diabetes risk is between the ages of 46 and 55," said LeBlanc. "Women who start menopause before or after that window should be aware that they are at higher risk, and should be especially vigilant about reducing obesity, eating a healthy diet and exercising. These lifestyle changes will help to reduce their risk for Type 2 diabetes."