Study of diabetic women shows osteoporosis begins after teens

By LOIS BAKER
News Services Editor

Researchers from UB, seeking to determine when the bone loss that results in osteoporosis in 19 percent of diabetic women begins, have found that mean bone density starts to decline sometime after the teen years.

Their study of 15 teen-age girls with long-standing Type 1 (insulin dependent) diabetes found that measures of bone mineral density were still within normal limits, but lower than their age-matched controls when adjusted for body mass index (BMI), a measure of obesity.

Study findings will be presented in San Francisco Sunday at the annual meeting of the Society for Pediatric Research.

"Osteoporosis is well-described in adult women with long-standing diabetes, but there is not a lot of information on when it starts," said Teresa Quattrin, associate professor of pediatrics and lead researcher on the study.

"The ability to assess various markers of bone metabolism-bone formation and bone resorption-is fairly new, so we don't have a natural history of osteoporosis in Type 1 diabetes. We need to follow young women prospectively so we can pinpoint the mechanism and perhaps intervene to stop the bone loss. Our study is a beginning."

The teen-agers in the study were all between the ages of 13 and 19 and had been receiving treatment for diabetes for at least five years in the diabetes clinic at The Children's Hospital of Buffalo. They were age-matched with teen-age girls who did not have diabetes.

Bone mineral density and bone mineral content measurements were taken of the spine, neck of the femur, wrist and total body by dual energy X-ray absorptiometry, or DEXA, one of the most accurate and advanced methods of determining bone status. The results were correlated with measures of glucose control and bone metabolism-osteocalcin, a marker of bone formation, and N-telopeptides, a marker of bone resorption.

Results showed that bone mineral density in the diabetic teens was lower than controls, but still within normal limits. When adjusted for BMI, which was higher in the diabetic teens than controls, there were statistically significant differences in bone mineral density at the spine and for the total body.

While glucose control was less than optimal in more than half of the patients, it was not a predictor of poorer bone mineral density, Quattrin said. In addition, bone mineral density was not influenced by higher insulin levels

Further studies in larger samples of patients, which UB researchers will be conducting, including prospective monitoring of girls with Type 1 diabetes, will help define the course and natural history of osteopenia and osteoporosis in women with Type 1 diabetes, Quattrin said.

Additional key researchers on the study were Jean Wactawski-Wende, assistant professor of gynecology and obstetrics, and Richard P. Donahue, professor of social and preventive medicine.