Renal insufficiency and magnesium deficiency correlate with a decreased formation of biologically active cholecalciferol: a retrospective observational study.
Level 4 - case-series / case-control
Retrospective cross-sectional observational study of outpatient laboratory values
PubMed 36334229 · doi:10.1007/s11096-022-01485-6
What was done
This retrospective observational study analyzed anonymized outpatient serum laboratory data collected over a 2-year period. The investigators evaluated relationships between 25-hydroxyvitamin D (25D), active 1,25-dihydroxyvitamin D (1,25D), serum magnesium, and renal function assessed via serum creatinine and estimated glomerular filtration rate (eGFR).
What was found
Renal function and magnesium levels showed negligible correlation with 25D levels (r = -0.144 and r = 0.030, respectively). Mean serum 1,25D concentrations decreased significantly from 106.5 ± 44.3 pmol/l in individuals with normal renal function to 51.7 ± 18.9 pmol/l in those with severe renal insufficiency (p < 0.01). There were weak positive correlations between 1,25D and eGFR (r = 0.317) and between 1,25D and serum magnesium (r = 0.217).
Why it matters
Standard assessment of 25D may overestimate functional vitamin D status in patients with kidney dysfunction or magnesium deficiency. The findings highlight the physiological role of renal function and magnesium as an enzymatic cofactor in synthesizing active 1,25D.
Limits
The abstract does not disclose the sample size, patient demographic characteristics, comorbidities, or medication/supplement use. Due to the cross-sectional, observational design, causality cannot be confirmed, and the observed correlations were weak.
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