Myopia prevalence and risk factors in children.

Purpose: To evaluate the prevalence and risk factors for pediatric myopia in a contemporary American cohort.

Methods: A cross-sectional study of pediatric patients enrolled in the Kaiser Permanente Southern California health plan was done. Eligible patients were 5- to 19-years old between January 1, 2008, through December 31, 2013, and received an ophthalmologic or optometric refraction. Electronic medical records were reviewed for demographic data, refraction results, and exercise data. Prevalence and relative risks of myopia (defined as ≤-1.0 diopter) were characterized. Age, sex, race/ethnicity, median neighborhood income, and minutes of exercise per day were examined as risk factors.

Results: There were 60,789 patients who met the inclusion criteria, of which 41.9% had myopia. Myopia was more common in older children (14.8% in 5- to 7-year olds, 59.0% in 17- to 19-year olds). Asian/Pacific Islander patients (OR 1.64, CI 1.58-1.70) had an increased rate of myopia compared to White patients as did African Americans to a lesser extent (OR 1.08, CI 1.03-1.13). Median neighborhood household income of $25,000-40,000 was associated with lower rates of myopia (OR 0.90, CI 0.83-0.97) compared to median neighborhood household incomes less than $25,000. Having at least 60 min of daily exercise was associated with lower prevalence of myopia (OR 0.87, CI 0.85-0.89).

Discussion: Myopia was common in this large and diverse Southern Californian pediatric cohort. The prevalence of myopia increases with age. Asian children are at highest risk for myopia. Exercise is associated with a lower rate of myopia and represents an important potentially modifiable risk factor that may be a target for future public health efforts.