THE INCIDENCE OF INSULIN-DEPENDENT DIABETES-MELLITUS IN URBAN DISTRICTS OF SHANGHAI (1989-1993)

A retrospective study on the incidence of insulin-dependent diabetes m ellitus (IDDM) among children aged 0-14 years was carried out from 198 9-1993 in urban Shanghai, China, The average annual population at risk (0-14 yr) consisted of 1,401,664 children, All the cases were collect ed from the hospitals (primary source) and from primary and middle sch ools and kindergartens (second source) with independent validation of case ascertainment. There were 53 IDDM cases from the primary source, 23 from the secondary source, with a total of 58, The ascertainment co rrected total number of IDDM cases was 67 by the capture-recapture met hod, The average crude annual incidence rate was 0.83 [95% confidence interval (CI) 0.61-1.04] and ascertainment corrected incidence rate 0. 96 (95% CI 0.80-1.12) per 100,000, Peak incidence fell in 1992 and in the 9 year-old group. The incidence of childhood IDDM in the urban dis tricts of Shanghai was reconfirmed to be the lowest in the world but b y comparing the results of former investigations a trend was found of increasing incidence of IDDM.