Incidence and cumulative risk of childhood cataract in a cohort of 2.6 million Danish children.

PURPOSE To determine the incidence and cumulative risk of childhood cataract in Denmark during 1980 to 2000. METHODS A cohort of 2,616,439 Danish children born between 1962 and 2000 was followed from 1980 or from the day of birth, whichever occurred later, until their 18th birthday, death, emigration, or diagnosis of cataract, whichever occurred first. Cases were ascertained from the Danish National Register of Patients (NRP) and validated by reviewing the medical records. They were divided into four groups: congenital/infantile (CI) cataract, traumatic cataract, complicated cataract, and "other" types of cataract. RESULTS After diagnostic validation, 1311 children with cataract (59% with CI cataract) were included in the study. During 1995 to 2000 the overall cumulative risk of childhood cataract was 108.4 per 100,000 children. There was no significant difference in incidence between girls and boys or over time (1980 to 2000) for CI, complicated, and "other" types of cataract. In contrast, the incidence of traumatic cataract was significantly higher among boys. It remained increased during the entire study period despite a 23% decrease per 5 years among boys. Sixty-six percent of the children diagnosed with CI cataract below 2 years of age underwent surgery within 1 year. CONCLUSIONS The stable incidence during a 20-year period of CI cataract and complicated cataract indicates that risk factors for these conditions have remained unchanged, whereas the marked drop of traumatic cataract among boys most likely reflects changed behavior and an increased focus on preventive measures.