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Obesity and low visual acuity (VA) in school-age children are major public health problems worldwide. Body mass index (BMI) has received significant attention for its role in the development and progression of various age-related ocular diseases. However, the relationship between BMI and low VA in school-age children and adolescence was not quite certain. The purpose of the present study was to investigate the association between BMI and low VA among adolescents in urban areas of Northeast China.
Data were obtained from the national survey on students’ constitution and health carried out by the government in 2014 in Liaoning Province, China. In this study, 8402 students of Han nationality aged 13 to 18 years in the urban areas were included. Unaided distance VA was measured using a retroilluminated logMAR chart with tumbling-E optotypes. Obesity was defined by using the references developed by Working Group on Obesity in China (WGOC). Logistic regression models were conducted to examine the relationship between BMI and low VA. All analyses were performed separately for both sexes.
The prevalence of low VA was 84.1% and 76.7% in females and males. Univariate logistic regression models suggested that higher prevalence of low VA was associated with older age, higher systolic blood pressure (SBP), diastolic blood pressure (DBP), shorter sleep duration, less time spent for outdoor activity, and more time spent for homework in both sexes, and associated with higher BMI only in females. In multivariable logistic regression models, each 1- kg/m2 increment in BMI was associated with 3.2% (95% CI: 0.3% -6.2%) increased hazard of low VA after adjusting for age, SBP, DBP, sleep duration, outdoor activity time and homework time for females. Overweight and obese females had the odds ratios of 1.167 (95% CI: 0.873-1.559) and 2.210 (95% CI: 1.262-3.868) for low VA compared with the reference group (normal-weight). Similar results were not observed for males.
Higher BMI was significantly associated with higher prevalence of low VA in adolescent females. Furthermore, there was a dose-dependent association between BMI categories and the prevalence of low VA, that is, females with higher BMI experienced greater prevalence of low VA.