Correlation of triglyceride–glucose index with myopia in adolescents: A cross-sectional analysis utilizing NHANES data from 1999 to 2008

The global prevalence of myopia among adolescents is rising. While metabolic factors are known to influence various health outcomes, their relationship with adolescent myopia remains poorly understood. This study aimed to investigate the association between the triglyceride–glucose (TyG) index and myopia severity in adolescents. This cross-sectional study included adolescents aged 12 to 19 years from the National Health and Nutrition Examination Survey (NHANES) 1999 to 2008 cycles. After excluding participants with missing data, 3579 adolescents were included. Weighted multivariable logistic regression, TyG quartile analysis, restricted cubic spline modeling, and subgroup interaction analyses were performed using fasting subsample weights and NHANES survey design variables. Among 3579 adolescents aged 12 to 19 years, the prevalence of myopia was 30.5%. After adjustment, the TyG index was significantly associated with moderate myopia (odds ratio [OR] = 1.68; 95% confidence interval [CI]: 1.07–2.63; P  = .024) and high myopia (OR = 2.91; 95% CI: 1.05–8.08; P  = .040). Participants in the highest TyG quartile had higher odds of high myopia than those in the lowest quartile (OR = 3.04; 95% CI: 1.05–9.25; P  = .042), whereas no significant association was observed for mild myopia. Restricted cubic spline modeling suggested an increasing estimated risk of moderate-to-high myopia at higher TyG levels. Subgroup analyses suggested possible effect modification by sex, race/ethnicity, poverty-to-income ratio, and body mass index, but these findings were exploratory. This cross-sectional NHANES analysis identified an association between a higher TyG index and moderate and high myopia in adolescents aged 12 to 19 years. While these results support further research on metabolic correlates of adolescent myopia, they do not demonstrate causality or define a clinically applicable cutoff.