To investigate the impact of age at onset on the prognosis of childhood IDDM in Japan.
The study population consisted of 987 prepubertal-onset and 345 pubertal-onset IDDM cases who were registered by two nationwide surveys and who were diagnosed between 1965 and 1979. The living status was identified as of 1 January 1990 with the ascertainment rate of 96.5%. Prognosis was evaluated by cause- and agespecific mortality rates and life-table analyses; in addition, an attained-age-matched case-control study was analyzed by conditional logistic regression.
The adjusted mortality rates per 100,000 person-years for the pubertal-onset cases were significantly higher than those of the prepubertal-onset cases (835 [95% CI 573–1,168] vs. 391 [283–526]). Life-table analyses revealed that the survival rate of the pubertal-onset cases was lower than that of the prepubertal-onset cases for each observation period. Life-table analyses after the age of 15 years indicated that the prognosis of pubertal cases was almost the same as that of the prepubertal cases despite having a shorter duration of diabetes. The attained-age–matched case-control study indicated that the pubertal onset was a potent determinant of death.
The prognosis of pubertal-onset IDDM was considerably poorer than that of prepubertal-onset IDDM.
