Risk factors for idiopathic congenital/infantile cataract.

PURPOSE To investigate maternal, demographic, and pre- and perinatal risk factors for idiopathic congenital/infantile (ICI) cataract. METHODS Based on national registries, a cohort of all children born in Denmark and aged 0 to 17 years during 1977 to 2001 was established, and congenital/infantile cataract cases were identified. Cases of unknown/idiopathic cause were included in the study. Associations between maternal, demographic, and pre- and perinatal factors with the development of cataract were investigated. RESULTS In a cohort of 2.9 million children, 1027 cases of congenital/infantile cataract were identified. Of the children in those cases, 629 were born in Denmark and had ICI. Bilateral isolated cataract cases were male dominated (62%; 95% confidence interval [CI], 56%-69%) but not unilateral isolated cases (40%; 95% CI, 34%-47%). Older age (> or =40 years) of mothers at delivery and caesarean section increased the risk of ICI cataract. Low birth weight (< 2000 g) was associated with a 10.6-fold (95% CI, 6.99-16.10) increased risk of bilateral, but not unilateral, ICI cataract. No significant associations were found with birth order, month/place of birth, or cigarette smoking during pregnancy. CONCLUSIONS Variables indicative of environmental influence were not associated with ICI cataract. Low-birth-weight children (< 2000 g) had a significantly increased risk of bilateral ICI, whereas no strong risk factors were found for unilateral cataract. Together with the sex difference, this suggests that the etiologies of bilateral and unilateral cataract are different.