Childhood overweight and obesity as risk factors for astigmatism: a longitudinal analysis.

OBJECTIVE: The association between body mass index (BMI) and astigmatism among children remains unclear. We conducted a longitudinal study to examine the relationship between BMI and astigmatism in a large pediatric cohort. DESIGN: A population-based retrospective cohort study. PARTICIPANTS: A total of 22,130 children aged 6 to 10 years from Maccabi Healthcare Services, Israel's second-largest health maintenance organization, who underwent refractive assessment between 2012 and 2022 and had at least 2 years of follow-up. METHODS: BMI was categorized using U.S. Centers for Disease Control and Prevention percentiles. Astigmatism was defined as ≥0.75 D and classified by severity and axis. Multinomial logistic regression assessed the associations between baseline BMI and astigmatism at follow-up, adjusting for sociodemographic factors. The population attributable fraction was calculated. RESULTS: Mean baseline age was 8.1 years, mean follow-up was 62.9 months, and 53.6% of participants were female. Astigmatism at follow-up increased across baseline BMI categories (p < 0.001). In multivariable analysis, overweight and obesity were associated with higher odds ratios (ORs) for low-to-moderate astigmatism (OR: 1.10; 95% CI: 1.01-1.21; p = .026 and OR: 1.24; 95% CI: 1.14-1.34; p < .001, respectively) and high astigmatism (OR: 1.40; 95% CI: 1.00-1.96; p = .048 and OR: 1.76; 95% CI: 1.30-2.38; p < .001, respectively). BMI was also associated with against-the-rule astigmatism, with the strongest association observed in obesity (OR: 1.41; 95% CI: 1.29-1.55; p < .001). Population attributable fractions were 4.3% for low-to-moderate astigmatism and 13.4% for high astigmatism. CONCLUSIONS: Overweight and obesity were associated with increased risk of astigmatism. Early vision screening in children with high BMI may support timely correction and reduce visual impairment.