AIMS/HYPOTHESIS: We examined the school marks of diabetic children in Sweden at the time of leaving compulsory education. Marks were examined in comparison with non-diabetic children and with special regard to age at onset of diabetes. SUBJECTS AND METHODS: The study involved 5,159 children who developed diabetes between 1 July 1977 and 1 July 2000, and 1,330,968 non-diabetic children. We linked the nationwide Swedish Childhood Diabetes Register to the Swedish School-Mark Register, which contains school marks for all children in Sweden at the time of leaving compulsory education (usually at 16 years old). Adjustment was made for potential confounders such as year of birth, maternal age, parity and educational level. RESULTS: The mean of all numerical school marks for diabetic children was slightly but statistically significantly lower than those of the referent children (3.15 +/- 0.01 [mean + SD] vs 3.23, p
