Causal Relationships Between Glycemic Traits and Myopia

Abstract

Purpose Little is known about whether sugar intake is a risk factor for myopia, and the influence of glycemic control remains unclear, with inconsistent results reported. This study aimed to clarify this uncertainty by evaluating the link between multiple glycemic traits and myopia. Methods We employed a two-sample Mendelian randomization (MR) design using summary statistics from independent genome-wide association studies. A total of six glycemic traits, including adiponectin, body mass index, fasting blood glucose, fasting insulin, hemoglobin A1c (HbA1c), and proinsulin levels, were used as exposures, and myopia was used as the outcome. The inverse-variance-weighted (IVW) method was the main applied analytic tool and was complemented with comprehensive sensitivity analyses. Results Out of the six glycemic traits studied, we found that adiponectin was significantly associated with myopia. The genetically predicted level of adiponectin was consistently negatively associated with myopia incidence: IVW (odds ratio [OR] = 0.990; P = 2.66 × 10 −3 ), MR Egger (OR = 0.983; P = 3.47 × 10 −3 ), weighted median method (OR = 0.989; P = 0.01), and weighted mode method (OR = 0.987; P = 0.01). Evidence from all sensitivity analyses further supported these associations. In addition, a higher HbA1c level was associated with a greater risk of myopia: IVW (OR = 1.022; P = 3.06 × 10 −5 ). Conclusions Genetic evidence shows that low adiponectin levels and high HbA1c are associated with an increased risk of myopia. Given that physical activity and sugar intake are controllable variables in blood glycemia treatment, these findings provide new insights into potential strategies to delay myopia onset.

Dietary composition plays a crucial role in the development of myopia through the inflammatory pathway: a Mendelian randomization study

“…Nevertheless, several plausible explanations can be considered: rstly, chronic in ammatory responses may incite damage and in ammatory reactions in ocular tissues, thereby disrupting the normal structure and function of the retina, optic nerve, and other ocular components, consequently promoting the onset of myopia; secondly, in ammatory responses encompass the release of diverse in ammatory mediators, such as cytokines, chemokines, and in ammatory regulators, which may exert detrimental effects on ocular tissues, such as augmented vascular permeability, cellular apoptosis, brosis, and oxidative stress, ultimately culminating in the development of myopia; thirdly, in ammation is intricately linked to the immune system, and aberrant immune system activation and in ammatory responses may impede normal ocular development and growth, consequently giving rise to myopia; lastly, in ammation-induced vascular alterations and aberrant blood circulation may engender inadequate oxygen supply, nutrient de ciencies, and metabolic disturbances in ocular tissues, thereby impinging upon the normal growth and development of the eye. However, these hypotheses necessitate further experimental investigations to substantiate their validity [53,54].Lastly, we have ascertained a negative correlation between the relative intake of proteins and fats and in ammation. Based on this nding, it is plausible to propose a potential mechanism whereby excessive protein and fat…”

Genetic causal association between type 2 diabetes, body mass index, smoking initiation and myopia：A mendelian randomization study

“…These studies may be affected by confounding factors such as education level and outdoor exposure. A previous Mendelian randomization study found a causal relationship between adiponectin, HbA1c and myopia, where low adiponectin levels and high HbA1c can increase the risk of myopia 24 . However, the study did not adjust for confounding factors such as BMI using multivariate Mendelian randomization, so its results require further validation.…”

“…In contrast, some studies have found that young adult men with low BMI have a higher incidence of myopia 28 , while others believe that there is no relationship between BMI and myopia [29][30] .The reason for these discrepancies in research may be that some studies did not include factors such as screen time exposure, outdoor time, dietary habits, and physical activity habits, and different studies may also be in uenced by race and regional factors. The Mendelian randomization study by Li et al did not nd a causal relationship between BMI and myopia 24 . This is inconsistent with our current research result that BMI is an important protective factor for myopia.…”

Dissecting the association between gut microbiota and hypertrophic scarring: a bidirectional Mendelian randomization study

“…While the IVW method is widely used, researchers should also consider sensitivity analyses and other methods, such as weighted median and MR-Egger regression, to assess the robustness of results and detect potential violations of assumptions. Therefore, results from MR were deemed meaningful if the IVW method identified a significant association ( p < 0.05), and concordantly, two additional methods, MR-Egger regression and weighted median (WM), also indicated effects in the same direction ( Li FF et al, 2023 ).…”

“…A higher F-statistic indicates a stronger instrument. Moreover, our analysis was constrained to results derived from a minimum of three shared SNPs ( Li FF et al, 2023 ).…”