[Family history and risk of insulin-dependent diabetes mellitus: a population-based case-control study]

Insulin-dependent diabetes mellitus (IDDM) is a worldwide occurrence disease of childhood with genetic, environmental and familial risk factors. Our study aims to evaluate family history as a determinant of IDDM. In a population-based case-control study informations on all incident IDDM cases, age 0-14, diagnosed between January 1st 1990 and December 31st 1996 were taken from the IDDM population-based register of the Abruzzo Region. The control group was taken from the lists of children attending family paediatricians. The family history data collection for IDDM and non insulin-dependent diabetes (NIDDM) were obtained by a questionnaire, administered to parents. Risk of IDDM associated with familiarity in first and second degree relatives was estimated using conditional regression analysis. Our results show that the risk of developing IDDM is increased by positive family history (OR = 3.99; 95% c.i. 1.56-10.23). The risk of IDDM for children whose fathers or brothers are affected by IDDM is respectively 11 and 20 times higher than for children with no family history. Family history for NIDDM does not influence the risk.