Myopia and BMI: a nationwide study of 1.3 million adolescents

Abstract

ObjectiveThis study analyzed the association between adolescent BMI and myopia severity.MethodsThis cross‐sectional study comprised 1,359,153 adolescents who were medically examined before mandatory military service. Mild‐to‐moderate and high myopia were defined based on right‐eye refractive data. BMI was categorized based on the US age‐ and sex‐matched percentiles. Logistic regression models were applied separately for women and men to estimate odds ratios (ORs) for myopia per BMI category.ResultsA total of 318,712 adolescents had mild‐to‐moderate myopia and 23,569 had high myopia. Compared with low‐normal BMI (reference group), adjusted ORs for mild‐to‐moderate and high myopia increased with increasing BMI status, reaching 1.39 (95% CI: 1.23‐1.57) and 1.73 (95% CI: 1.19‐2.51) for men with severe obesity, respectively, and 1.19 (95% CI: 1.12‐1.27) and 1.38 (95% CI: 1.14‐1.65) for women with mild obesity, respectively. ORs for mild‐to‐moderate and high myopia were also higher in men with underweight (OR = 1.20; 95% CI: 1.18‐1.23 and OR = 1.39; 95% CI: 1.30‐1.47) and women with underweight (OR = 1.06; 95% CI: 1.03‐1.09 and OR = 1.12; 95% CI: 1.04‐1.22). The overall size effect was greater for men than women (pinteraction < 0.001), in whom the group with severe obesity did not reach statistical significance.ConclusionsBMI was associated with myopia in a J‐shaped pattern, with the size effect being greater for adolescent men than women. This study indicates that both low BMI and high BMI are associated with mild‐to‐moderate and severe myopia.

Analysis of Secondhand Smoke Exposure and Myopia Among Children Aged 6 to 8 Years in Hong Kong

“…Model 1 included the established fundamental confounders of age, sex, and parental myopia. 9,35 Model 2 added other well-recognized confounders of BMI, outdoor time, nearwork time, and family income, [36][37][38][39] and the interaction effects of age and SHS exposure on myopia were further tested. Analyses of the association between SHS exposure and ocular parameters (SE and AL) were eye-based; data from both eyes were included, using generalized estimating equations with standard errors to adjust for intereye correlation.…”

Body mass index and visual impairment in Israeli adolescents: A nationwide study

“…35 Finally, other common factors might influence both BMI and VI, thereby shaping their interconnection. Myopia, affecting up to 30% of our source population, 36 similarly shares a J-shaped association with BMI 19 and might culminate in ocular changes leading to BCVA reduction. 37 In this context, an analysis of adolescents without moderate-to-severe myopia demonstrated comparable point estimates, thereby weakening the possibility of confounding by myopia as a cause for VI.…”

“…Body measurements included weight and height measured barefoot and in underwear, using a beam balance and stadiometer. 16,19 Body mass index (BMI) was calculated as the weight (kg) divided by the squared height (m 2 ). BMI was classified according to the age-(in months) and sexadjusted percentiles of the United States Centers for Disease Control and Prevention (CDC), which were validated for Israeli adolescents.…”

“…In some adolescents, BCVA and refraction were recorded based on the documentation of measurements performed by an optometrist or ophthalmologist. [17][18][19] BCVA <6/9 in one eye defined unilateral VI; BCVA <6/9 in both eyes defined bilateral VI; BCVA ≥6/9 in both eyes defined normal vision. [8][9][10][11]…”

“…To account for possible confounding by other comorbidities, we included only adolescents with unimpaired health status, as evaluated during the medical screening process.b. In light of recent evidence indicating an association between BMI and myopia using a similar dataset, we excluded adolescents with moderate-to-severe myopia (defined as right eye spherical equivalent ≤ À3.0 diopters) to address the possibility of confounding by BCVA reduction associated with myopia 19.…”