IDDM INCIDENCE IN A MULTIRACIAL POPULATION - THE HAWAII IDDM REGISTRY, 1980-1990

OBJECTIVE - The Hawaii IDDM Registry was created to determine the inci dence rate of IDDM among children aged <15 years on Oahu between 1980 and 1990. Because of the multiracial population living in Hawaii, it i s an ideal state in which to study the effect of migration on IDDM inc idence. RESEARCH DESIGN AND METHODS - Data were collected by a retrosp ective hospital chart review and physician survey. Registry criteria i ncluded 0-14 years of age at IDDM diagnosis and primary residence on O ahu. Children who were military dependents were excluded. Denominator data were compared from two sources. RESULTS - A total of 113 new-onse t IDDM cases were identified. Case ascertainment was 97%. The unadjust ed annual incidence rate was 7.04-7.61 per 100,000 (95% CI 5.83-9.19), depending on which denominator source was used. Race- and ethnicity-s pecific rates varied greatly (all rates per 100,000): part Hawaiian, 1 5.34-16.58; Caucasian, 6.21-6.71; Filipino, 3.66-3.96; and Japanese, 2 .85-3.08. Temporally, the incidence fluctuated between a low of 2.96 p er 100,000 in 1981 to highs of 11.11 and 11.85 per 100,000 in 1985 and 1989, respectively. Ascertainment-corrected rates for these years (3. 70, 11.76, and 13.48 per 100,000, respectively) show that the fourfold incidence increase between 1980 and 1989 was not due to ascertainment differences. CONCLUSIONS - IDDM incidence among children <15 years of age in Hawaii was the lowest documented in the U.S. The incidence amo ng part-Hawaiian children was 2.5 times greater than that of Caucasian children in Hawaii. IDDM incidence rates among Japanese children in H awaii were comparable with rates in Japan. The temporal variation in I DDM incidence corresponded with a mid-1980s pandemic of IDDM documente d elsewhere.