Incidence of type 1 diabetes in children under 15 years in northern Thailand, from 1991 to 1997.

The annual incidence of Type 1 diabetes in children under 15 years in northern Thailand from 1991 to 1997 was a retrospective study by analyzing the data gathered from the Pediatric Endocrine Division, Faculty of Medicine, Chiang Mai University and through a mail survey to 202 hospitals in the government and private sector in northern Thailand. The response to the mail survey from 1991 to 1992 and 1993 to 1997 was 90.1 per cent and 94.5 per cent respectively. During the seven year period, 76 new cases of Type 1 diabetes were identified. The crude annual incidence ranged from 0.31-0.56/100,000 per year, with an average incidence of 0.37/100,000 per year (95% C.I. = 0.29-0.46). This very low figure had risen 2.2 fold (over 100%) from that reported in 1984. The annual incidence was relatively constant from 1991 to 1996, although there was a moderate rise in 1997 (0.56/100,000 per year). There was no statistically significant difference between the annual incidence of 1996 and 1997. It remains for further studies to confirm the trend of increased incidence. The median age of onset was 11 years, whereas, the peak age of onset occurred in the 10-14 year age group of both sexes. There was a greater incidence among female in this study. These date confirm the need to develop a national registry of Type 1 diabetes for further epidemiological research.