Study Reveals Pregnancy and Diabetes Link : Medicine: The incidence of one type of diabetes increases with successive pregnancies, according to a UC San Diego study.

A woman’s risk of developing Type II diabetes, also known as adult-onset diabetes, increases with each successive pregnancy, according to results of a UC San Diego study published in today’s New England Journal of Medicine.

The increased risk of developing Type II diabetes and impaired glucose tolerance, a condition that leads to diabetes, exists “independent of age, obesity and a family history of diabetes,” conditions normally used to predict who will develop the disease, according to the study’s principal author, Donna Kritz-Silverstein, an epidemiologist in UCSD’s department of community and family medicine.

However, the increased risks associated with multiple pregnancies are slight, and the study should not be used as the basis for family planning, co-author Elizabeth Barrett-Connor, a medical doctor who is chairman of the department of community and family medicine, said.

“I certainly wouldn’t do my family planning based on this study,” Barrett-Connor said. “Rather, we think this study is important because it suggests something new about how people may develop diabetes.”

The study “could be a significant observation,” according to Dr. Orville Kolterman, adjunct professor of medicine and director of UC San Diego Medical Center’s Clinical Diabetes Program. The study suggests that “there’s now another risk factor for the subsequent development of . . . what is a complex disease,” said Kolterman, who was not involved in the article published in the New England Journal of Medicine.

“It’s an exciting observation,” said Dr. Roger Lerner, an endocrinologist and president-elect of the Los Angeles Chapter of the American Diabetes Assn. “We’d like to hear more . . . and have it confirmed in other population studies.”

Researchers now must seek an understanding of how multiple pregnancies affect the “diabetic gene” responsible for Type II diabetes, Lerner said. “The cause or gene (responsible for Type II diabetes) is not yet known,” Lerner said. “That’s the real issue, and this (study) may be one way to help uncover that underlying factor.”

Type II diabetes, also known as non-insulin-dependent diabetes mellitus, or NIDDM, differs from juvenile diabetes, an inherited medical condition that develops in infancy or childhood. Juvenile diabetes, which can lead to serious health problems, often must be treated with medication. Adult-onset diabetes, however, usually is treated by adjusting a patient’s diet and exercise.

Data used in the study was gathered from 1,186 women observed between 1984 and 1987. Those women are part of Barrett-Connor’s long-range study of more than 6,000 residents of Rancho Bernardo. That study, which began in 1972, is funded by the National Institutes of Health. It is designed to identify risk factors for some common disorders associated with aging.

The study dealt with women from the ages of 40 to 92 who were not previously diagnosed as having Type II diabetes. The women did not have family histories of diabetes and were “actually leaner” than most women in related medical studies, Kritz-Silverstein said.