Childbirth is a type 2 diabetes risk factor

NEW YORK (Reuters Health) - Women who have given birth to five or more infants have an increased risk of developing type 2 diabetes mellitus, researchers report in the journal Diabetes Care. This appears to be the case, even after considering the influence of other known risk factors, such as obesity and socioeconomic status.

Dr. Wanda K. Nicholson and colleagues at the Johns Hopkins School of Medicine in Baltimore, Maryland, came to this conclusion after conducting a study with more than 7,000 Caucasian and African-American women.

The subjects were between 45 and 64 years of age and the average follow-up time was nine years. The women were grouped according to child birth history, defined as no live births (including stillbirths and miscarriages), one to two live births, three to four live births, or more than four live infant births.

There were 754 cases of type 2 diabetes during follow-up. Type 2 diabetes rates were highest among the women with the most births and lowest among women who had no more than two live births.

The researchers acknowledge that the bulk of diabetes risk is due to obesity and lower socioeconomic status. However, after adjusting for these recognized risk factors as well as clinical factors, inflammatory markers and lifestyle factors, multiple births remained a risk factor for type 2 diabetes.

Whether the link between childbirth and diabetes is biological or due to lifestyle factors is unknown. The investigators conclude that the association may be better understood after studies of "specific, pregnancy-related weight gain measures, lifestyle factors and changes in socioeconomic status."

SOURCE: Diabetes Care, November 2006.