Incidence of insulin-dependent diabetes mellitus among Sardinian-heritage children born in Lazio region, Italy.

Background: The relative importance of genetic and environmental factors in causing insulin-dependent diabetes mellitus (IDDM) is unknown. We studied this question by assessing the incidence of the disease in children, born in a region with a low incidence of IDDM (Lazio), but whose parents came from a region with high incidence (Sardinia).

Methods: We identified all IDDM cases that occurred between 1989 and 1994.