title: Incidence of insulin-dependent diabetes mellitus among Sardinian-heritage children born in Lazio region, Italy.
abstract: 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. We used as the denominator the number of children aged 0-14 born in Lazio of Sardinian parents to calculate incidence. We compared this rate with the incidences of IDDM in the populations of Lazio and Sardinia.
  
  
  RESULTS
  The age-adjusted incidence of IDDM in Sardinian-heritage children born and living in Lazio was 33.8 per 100,000 per year (95% CI 7.0-99.0) for those with two Sardinian parents, and 15.9 (8.7-26.6) for those with only one parent from Sardinia. The former incidence was not different from that recorded in Sardinia (34.4, 31.3-37.9), but was fourtold that of Lazio-heritage children (7.9, 7.1-8.8).
  
  
  CONCLUSIONS
  Our results show that two different ethnic groups living in the same region have a fourfold difference in incidence of IDDM. Children of Sardinian-heritage born in Lazio have the same incidence as the population of origin, which is genetically prone to the disease. Moreover, children with one Sardinian parent had a rate half that of Sardinians and double that of the indigenous population. We conclude that in a given population genetic susceptibility determines the frequency of IDDM in response to the environmental challenge.
authors.affiliation: Centro per le Malattie Dismetaboliche e l'Arterlosclerosi, Associazione ME.DI.CO, Cagilari, Italy.
authors.forename: S
authors.initials: S
authors.lastname: Muntoni
authors.forename: M T
authors.initials: MT
authors.lastname: Fonte
authors.forename: S
authors.initials: S
authors.lastname: Stoduto
authors.forename: G
authors.initials: G
authors.lastname: Marietti
authors.forename: C
authors.initials: C
authors.lastname: Bizzarri
authors.forename: A
authors.initials: A
authors.lastname: Crinò
authors.forename: P
authors.initials: P
authors.lastname: Ciampalini
authors.forename: G
authors.initials: G
authors.lastname: Multari
authors.forename: M A
authors.initials: MA
authors.lastname: Suppa
authors.forename: M C
authors.initials: MC
authors.lastname: Matteoli
authors.forename: L
authors.initials: L
authors.lastname: Lucentini
authors.forename: L M
authors.initials: LM
authors.lastname: Sebastiani
authors.forename: N
authors.initials: N
authors.lastname: Visalli
authors.forename: P
authors.initials: P
authors.lastname: Pozzilli
authors.forename: B
authors.initials: B
authors.lastname: Boscherini
authors.forename: S
authors.initials: S
authors.lastname: Muntoni
mesh_terms: D000293:Adolescent; D002648:Child; D002675:Child, Preschool; D003922:Diabetes Mellitus, Type 1 / Q000208:ethnology* / Q000209:etiology / Q000235:genetics*; D004777:Environment; D005260:Female; D006801:Humans; D015994:Incidence; D007558:Italy / Q000453:epidemiology / Q000208:ethnology; D008297:Male; D010290:Parents