In the present study, we found that the consumption of SBBs was not significantly associated with the incidence of myopia in the NHANES population under 40 years of age. Furthermore, there were no associations between SSBs and the risk of myopia.
The escalating prevalence of myopia raises significant concerns for public health due to its severe complications such as retinal detachment, glaucoma, and macular degeneration, which are the causes of vision impairment and loss7. SSBs are a prominent part of dietary intake in many societies, especially among young people23, 24. Given this prevalence, it is crucial to identify the potential health impacts associated with SSBs. A few previous studies have identified a possible relationship between high dietary intake of desserts, carbonated drinks, and refined carbohydrates and the incidence and progression of myopia 20, 21, but our research did not find a significant association between SSB consumption and the incidence of myopia in individuals under 40 years based on the NHANES population, even SSBs constitutes a substantial part of the daily sugar intake23, 24.
Sugar intake elevates insulin levels acutely and chronically, this diet-induced hyper-insulinaemia chronically up regulates insulin-like growth factor-1 (IGF-1), which may operate synergistically with plasma reductions in insulin-like growth factor binding protein-3 (IGFBP-3) to accelerate scleral tissue growth27. Sande et al28 reviewed the role of the gap junction delta-2 (GJD2) gene in the refractive error, pointing a link between GJD2 and metabolic control of glucose levels via insulin and glucagon, which have a causal effect on eye growth in chickens29–32. Genetic evidence shows that low adiponectin levels and high HbA1c are associated with an increased risk of myopia33. As for epidemical research, it has been reported that higher refined carbohydrates are associated with higher odds of myopia in girls of age 4–18 years in French 20.While it was also found that intake of specific dietary factors including SSB were not significantly associated with myopic incident at age of 9-year among Singaporean children through a prospective study15, which is consistent with our finding.
To determine if the increased consumption of SBBs is associated with gender, education attainment, and socioeconomic status, we computed the VIF of all covariates to exclude the potential for multicollinearity in multi-regression Model 3. The result implies that there isn't a specific gender or social status more inclined to consume SBBs.
Our findings have two implications for public health policies and interventions. Firstly, the finding emphasized the need for comprehensive strategies for myopia prevention that extend beyond dietary considerations, as our study did not identify SSB consumption as a significant risk factor, just as there was no recommends on specific advice to prevent myopia in dietary aspect in a Singapore cohort study15. This implies that environmental and genetic factors may play more substantial roles in the development of myopia, including near work, outdoor exposure, and genetic predisposition. Secondly, our research offers some reassurance regarding the influence of SSBs on ocular health, particularly in relation to myopia. Although it is well-documented that excessive intake of SSBs results in multiple health complications such as obesity, diabetes and nonalcoholic fatty liver disease22, 34, our study suggests that concerns regarding its contribution to myopia may be unwarranted.
Our study has several advantages and implications. It should be noted that the analysis includes the application of sampling weights attributed to each participant. These weights are essential in facilitating statistical inferences and extrapolating our findings to a broader population beyond the sample size of myopia instances. By incorporating these weights, our study guarantees dependable conclusions and precise statistical power. In addition, our study used PSM to eliminate confounding factors, improving the credibility of the results.
This study faces several limitations. Firstly, these results do not entirely rule out the potential impact of overall diet or other nutritional factors on myopia development. For instance, while SSBs did not show a direct link, other sugar-based or high Glycemic Index (GI) foods might still play a role. The lack of association can also be due to the possibility that the effects of SSBs on myopia might only manifest after a specific age or under certain conditions. Secondly, the data used was self-reported, which could have led to inaccuracies due to recall bias. Also, the study was cross-sectional, restricting us from establishing a cause-effect relationship between SSB consumption and myopia.