A major improvement in the prognosis of individuals with IDDM in the past 30 years in Japan. The Diabetes Epidemiology Research International Study Group.

OBJECTIVE

To evaluate the time trends of mortality among individuals with IDDM in Japan.

RESEARCH DESIGN AND METHODS

A historical prospective study of two independent population-based cohorts composed of individuals who were diagnosed between 1965 and 1969 (1960s cohort) and between 1975 and 1979 (1970s cohort), which included 286 IDDM patients (onset age < 18 years) for the 1960s cohort and 779 patients for the 1970s cohort, was performed. After 10 years of observation, mortality status and causes of deaths between the two cohorts were compared.

RESULTS

The age-adjusted mortality rate per 100,000 person-years of the 1960s cohort was 754 (95% CI, 471-1,141); in contrast, that of the 1970s cohort was only 196 (95% CI, 107-329) (P < 0.001). The standardized mortality ratio of the 1960s cohort was 1,432 (95% CI, 898-2,161), and that of the 1970s cohort was 489 (95% CI, 267-821). Analyses of the causes of deaths revealed a marked decline in recent years in the number of deaths by acute complications and renal disease.

CONCLUSIONS

A major decline in the mortality of diabetic children in Japan may be attributed to the dramatic changes in the quality of care and medical infrastructure that occurred after the mid-1970s.