Dietary Magnesium Intake Level Modifies the Association Between Vitamin D and Insulin Resistance: A Large Cross-Sectional Analysis of American Adults

Associations between Vitamin D Levels and Insulin Resistance in Non-Diabetic Obesity: Results from NHANES 2001-2018

OBJECTIVE

Obesity is often accompanied by insulin resistance (IR) and diabetes. We explored the association between vitamin D levels and IR in non-diabetic obesity.

METHODS

We conducted a cross-sectional study based on the data of National Health and Nutrition Examination Survey (NHANES) from 2001 to 2018. Non-diabetic individuals (aged ≥20 years) with obesity (BMI ≥ 30kg/m2) were included in the study. And HOMA-IR ≥ 2.5 was defined as IR. The multivariable linear regression models were constructed to evaluate the associations between levels of 25(OH)D and HOMA-IR. We calculated the odds ratio (OR) and 95% confidential intervals (CIs) for associations between 25(OH)D deficiency and IR in obesity using multivariable logistic regression models.

RESULTS

Overall, a total of 3887 individuals were included in this study. Serum vitamin D level was significant lower in obesity participants with IR than that of non-IRs. The linear regression models showed that vitamin D level was inversely associated with HOMA-IR in obesity after adjusting for covariables (β=-0.15, 95%CI (-0.28, -0.02), p = 0.028). And the multivariable logistic regression models indicated an association between vitamin D deficiency and IR in obesity ((OR= 1.38, 95%CI (1.09-1.73), p = 0.007)). The further stratified regression analyses among different BMI demonstrated that vitamin D deficiency (OR = 1.4, 95%CI (1.05,1.86), p = 0.022) only contributed to developing IR in class I obesity.

CONCLUSION

This study suggested an association of vitamin D levels with IR in obesity. And vitamin D deficiency contributed to IR in class I obesity.

The Significance of Low Magnesium Levels in COVID-19 Patients

Magnesium is the fourth most common mineral in the human body and the second richest intracellular cation. This element is necessary for many physiological reactions, especially in the cardiovascular and respiratory systems. COVID-19 is an infectious disease caused by SARS-CoV-2. The majority of people who become ill as a result of COVID-19 have mild-to-moderate symptoms and recover without specific treatment. Moreover, there are people who develop severe forms of COVID-19, which require highly specialized medical assistance. Magnesium deficiency may play a role in the pathophysiology of infection with SARS-CoV-2. The primary manifestation of COVID-19 remains respiratory, but the virus can spread to other organs and tissues, complicating the clinical picture and culminating in multiorgan failure. The key mechanisms involved in the disease include direct viral cytotoxicity, endothelial dysfunction, and exaggerated release of inflammatory cytokines. The aim of this review was to summarize the available data regarding the role of magnesium in COVID-19 patients and its particularities in different clinical settings.

Associations between dietary magnesium intake and handgrip strength were modified by serum vitamin D level among the US elderly

Objective

The present study aimed to evaluate the associations between dietary magnesium intake and handgrip strength, and whether these associations were affected by serum vitamin D status.

Methods

A total of 2,127 participants aged 60 and above from the National Health and Nutrition Examination Survey (NHANES) of the 2011-2014 cycles were included in the analyses. Magnesium intake was obtained by 24-h dietary recalls and 30-day dietary supplement. Participants in the lowest sex-specific tertile of magnesium intake were defined as having low magnesium intake. Serum 25-hydroxyvitamin D [25(OH)D)] concentrations were examined by using ultra-high performance liquid chromatography tandem mass spectrometry and categorized into three levels: deficient, suboptimal, and sufficient. Handgrip strength was determined by using a dynamometer. Multivariable linear regression models were used to investigate the associations between dietary magnesium intake and handgrip strength.

Results

Low magnesium intake was not associated with handgrip strength, but interactions between low magnesium intake and serum 25(OH)D level existed on handgrip strength. The stratified analyses found that only in participants with deficient serum 25(OH)D, low magnesium intake was associated with reduced handgrip strength. The combined analyses shown that participants with both low magnesium intake and deficient serum 25(OH)D had highest decrease of handgrip strength.

Conclusion

Findings suggested that low magnesium intake was associated with reduced handgrip strength only in participants with deficient serum 25(OH)D. Increased magnesium intake was recommended for participants with deficient serum 25(OH)D in maintaining muscle strength.