Myopia (near-sightedness) is an eye disorder caused by a complex interaction between nature (related to genetic factors) and nurture (related to environmental factors). This study investigated whether environmental risk factors can influence the genetic effect in children who are developing myopia.
Previous research has identified environmental risk factors associated with myopia. These include extended near work and minimal outdoor exposure. Previous research also indicates that “lifestyle in childhood is most likely the major cause of the rapid rising prevalence.” What previous research has not determined is whether lifestyle can influence or alter the outcome of a genetic susceptibility for myopia. Studies focusing on the gene-environment interaction in children have been limited. The current study addressed this gap in the literature.
Data for this investigation was based on 3422 children from The Netherlands who were participating in the birth-cohort study Generation R. When the children were nine-years old, they completed an extensive eye examination and their parents completed a lifestyle questionnaire which included items relating to known environmental risk factors. Parents also provided information about their own eye health status.
Researchers used the data to calculate environmental risk scores and genetic risk scores for each child. They then calculated the predictive value of the gene-environment interaction and investigated the relationship between parental myopia and genetic and environmental factors. From these calculations, they were able to assess the predictive value of the environmental and genetic variables to identify children at risk for early onset myopia.
Twelve percent of the children in this sample of nine-year-olds had myopia. The children with myopia were more likely to be non-European, tended to have a short reading distance, and generally spent more time on reading. Children with myopia also had a tendency towards spending less time outdoors and were more likely than their peers to have one or two parents with myopia. The environmental and genetic factors contributing to myopia for children in this study were about equal. The strongest influence occurred when the two factors were combined.
The authors suggest that changes in lifestyle – including spending more time outdoors – may postpone or prevent the development of myopia in children. “Since myopia genes are common in the population, adjustment of lifestyle should be a major focus in the prevention of myopia.”
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