High incidence of juvenile Graves' disease in Hong Kong.

Abstract

Childhood Graves' disease has been reported to be rare and epidemiological data on its incidence are limited. In our Paediatric Endocrine Clinic, Graves' disease was the most common thyroid disorder seen. There is no previous epidemiological study on Graves' disease in Chinese children. This study was performed to determine the incidence of childhood Graves' disease in Hong Kong Chinese. We established a registry of childhood Graves' disease in 1990 at our centre, which has a catchment population of 1,010,000 with 240,000 under 15 years of age. Graves' disease was diagnosed on clinical features, diffuse thyroid gland enlargement, elevated free thyroxine or triiodothyronine levels with suppressed TSH level. All confirmed cases were recorded prospectively. Population data were obtained from the Statistics Department of the Hong Kong Government. Forty-six Chinese children under 15 years of age had a confirmed diagnosis of Graves' disease during the study period from January 1990 to December 1994. The overall incidence was 3.8/100,000/year with a 95% confidence interval of 1.8-7.3/100,000/year. Incidence was low in children under 4 years. The highest incidence was in girls between 10 and 14 years of age at 15.5/100,000/year. The cumulative incidence for boys and girls of developing Graves' disease during the first 15 years was 11 and 104 per 100,000 respectively. Our data demonstrate a very high incidence of Graves' disease in Hong Kong Chinese children, with an overall incidence about 5 times that reported in Danish children. A female predominance was found in all three age groups (0-4, 5-9 and 10-14 years) and was particularly striking in the adolescent girls.