A study recently published in Nutrients evaluated the association between retinal vein occlusion (RVO) prevalence and magnesium (Mg) intake.
Give me some background.
RVO largely affects older adults and has risk factors in common with cardiovascular disease—but usually does not require a comprehensive systemic examination.
While there has been an improved understanding of the pathophysiology of RVO, identifying its modifiable risk factors is crucial to identify potential pathways for preventative and therapeutic interventions, the study authors noted.
Now bring in magnesium.
Mg is an essential dietary mineral fundamental to several physiological processes, including:
Note: All of these are critical factors in the pathogenesis of vascular occlusions, suggesting its potential to reduce the risk of cardiovascular disease.
- Further: Mg deficiency has been linked to the development of atherosclerosis, which may promote vascular calcification and lipid accumulation in vascular plaques.
Now talk about the study.
In this cross-sectional study, investigators included 16,358 participants (aged ≥19 years) from the Korean National Health and Nutrition Examination Survey (KNHANES) 2017-2021.
- Note: The KNHANES is a government-led, population-based, cross-sectional survey designed to evaluate the health and nutritional status of the Korean population.
And the setup?
First: The research team categorized participants into three groups (listed below) based on their daily Mg intake and compared the characteristics between groups:
- Low (< 120 mg)
- Intermediate (men: 120-300 mg, women 120-400 mg)
- Sufficient (men: ≥300 mg, women: ≥400 mg)
How RVO was assessed: Via fundus imaging or self-reported survey results.
And the findings?
The prevalence of RVO in the cohort was 0.7%.
Compared to the non-RVO group, the RVO group was characterized by:
- Older individuals
- Fewer current alcohol consumers
- A higher prevalence of hypertension and chronic kidney disease
- Lower intake of fiber, iron, calcium, Vitamin E, and Mg
Expert opinion?
After full adjustment, sufficient Mg intake was significantly associated with a 64% reduced risk of RVO (odds ratio [OR] 0.36, 95% confidence interval [CI] 0.18-0.71, p = 0.003).
This association was particularly notable among specific subgroups, including those:
- Aged 19-59 years (OR 0.18, 95% CI 0.04-0.82, p = 0.027)
- Diagnosed with hypertension (OR 0.29, 95% CI 0.13-0.67, p = 0.003)
- Diagnosed without glaucoma (OR 0.33, 95% CI 0.15-0.71, p = 0.004)
Expert opinion?
“We speculate that younger individuals may benefit more from the protective effects of Mg due to greater vascular plasticity, better endothelial function, and less cumulative vascular damage,” the study authors explained.
Moreover: Patients with hypertension may also experience stronger effects due to Mg’s role in maintaining vascular health and blood pressure homeostasis.
Anything else?
The study authors reported that a higher fiber intake was significantly associated with reduced RVO risk, however the OR was not sufficiently low to establish its clinical significance—suggesting the need for further research on this potential link.
Limitations?
These included:
- The cross-sectional design limited the establishment of causality between Mg intake and RVO risk—in fact the observed inverse association between the two should be interpreted with caution
- Due to the relatively small proportion of participants with RVO, residual confounding factors (ex., genetic predispositions, dietary and lifestyle factors) could have influenced the observed associations
- In the KNHANES dataset, blood Mg concentrations were not analyzed and it was not possible to distinguish between RVO and arterial occlusions
- Also, ocular risk factors for RVO and distinctions between RVO subtypes were not accounted for in the analysis
- Dietary Mg intake and RVO diagnosis were assessed through self-reported surveys in 19 cases, which may have introduced recall bias and potential misclassification
- The study population was limited to Korean adults, potentially reducing the generalizability of the findings
Take home.
These findings suggest that sufficient Mg intake may reduce RVO risk among:
- Adults aged <60 years
- Individuals with hypertension
- Those without glaucoma
Next steps?
The study authors highlighted that future prospective studies should:
- Confirm the protective effect of Mg supplementation in preventing RVO
- Determine its underlying mechanisms
- Identify the optimal dosage and safety profile of Mg intake
- Explore its potential preventative effect in high-risk populations and across diverse subgroups