This study involved a multiethnic cohort of 5711 six-year-old children living in a densely populated area of the Netherlands. The aim of the study was to examine whether differences in myopia prevalences in socioeconomic risk groups could be explained by differences in lifestyle factors.
A two-stage ophthalmic examination revealed that 137 participants (2.4%) had myopia. The ophthalmic examination results were paired with data collected through a parent questionnaire focusing on the child's daily activities, ethnicity, factors representing family socioeconomic status. and housing.
Findings indicated that children with myopia spent more time indoors and less time outdoors than children without myopia. The children with myopia also had lower vitamin D levels, a higher body mass index, and participated less in sports. Additionally, children of non-European descent, low maternal education, and low family income were more often myopic. They were also more likely to live with unmarried parents and to live in a rental home. Young children from families with a non-European ethnic background and/or a low socioeconomic status tended to be more often myopic in Rotterdam, one of the most densely-populated cities in The Netherlands.
These findings suggest that the risk profiles based on education and income aren't the cause of myopia, but reflect certain lifestyle factors that are more directly involved in the development of myopia. Some of these lifestyle factors (including both behaviors and living conditions) can be modified to reduce the risk of myopia. Increasing the level of outdoor activity is one important factor that can be modified for individual children. This modification can also be implemented as a population intervention by dedicating more school time to outdoor activities.
This research is consistent with other studies providing evidence that children's daily activities are an important cause of myopia and suggesting that lifestyle changes with more time outdoors is one way to reduce children's risk of developing myopia.