Interaction Between Magnesium Intake and Serum 25-Hydroxyvitamin D Levels in Modulating the Likelihood of Chronic...

While vitamin D is known to facilitate intestinal magnesium (Mg) absorption, the combined effect of these nutrients on the prevalence of chronic kidney disease (CKD) remains unclear. This study investigated how serum 25-hydroxyvitamin D [25(OH)D] levels modify the association between dietary Mg intake and CKD.

Cross-sectional subject evaluations were performed using data from the 2009-2014 National Health and Nutrition Examination Surveys. The assessment of dietary Mg intake conducted through a 24-hour dietary recall, while the determination of 25(OH)D serum levels was accomplished using a radioimmunoassay kit. CKD was defined based on the presence of albuminuria and estimated glomerular filtration rate. A probability sample (n = 12,435) aged ≥20 years was drawn from the noninstitutionalized civilian population of the United States. Multiple regression analysis was employed to ascertain the independent association between total Mg intake, serum 25(OH)D, and CKD, while controlling for age, sex, race/ethnicity, body mass index, and energy intake. Given the intricate nature of the survey design, all analyses were weighted.

A notable correlation was observed between increased Mg consumption and a reduced likelihood of CKD (odds ratio [OR] = 0.836, 95% confidence interval [CI]: 0.729-0.959, P = .014). The relationship between Mg intake and the prevalence of CKD was found to differ based on the levels of 25(OH)D. Specifically, among individuals with 25(OH)D levels equal to or below 50 nmol/L, no significant association was observed (OR: 1.054, 95% CI: 0.730-1.522, P = .764). In contrast, among those with 25(OH)D levels greater than 50 nmol/L, higher Mg intake was associated with lower odds of CKD (OR: 0.796, 95% CI: 0.685-0.926, P = .006). A significant interaction was observed (interaction P value = .002). Notably, among vitamin D-sufficient participants with moderate to severe CKD (stages G3-G5), each unit increase in Mg z-score was associated with 33% lower odds of CKD (OR = 0.67, 95% CI: 0.49-0.92), with a clear dose-response trend (P for trend = .023).

The renal protective effect of Mg consumption appears dependent on adequate vitamin D status, particularly in advanced CKD, suggesting combined nutritional supplementation strategies may warrant investigation in CKD prevention.