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Investigation of the Vitamin D Metabolite Ratio (VMR) as a Marker of Functional Vitamin D Deficiency: Findings from the SarcoPhAge Cohort

2024; Multidisciplinary Digital Publishing Institute; Volume: 16; Issue: 19 Linguagem: Inglês

10.3390/nu16193224

2072-6643

Aurélie Ladang, Anne-Sophie Gendebien, Stéphanie Kovacs, Céline Demonceau, Charlotte Beaudart, Stéphanie Peeters, Majed S. Alokail, Nasser M. Al‐Daghri, Caroline Le Goff, Jean‐Yves Reginster, Olivier Bruyère, Étienne Cavalier,

Pharmacological Effects and Toxicity Studies

Background: The vitamin D metabolite ratio (VMR) has recently been identified as a potentially better indicator of vitamin D deficiency than 25-hydroxyvitamin D (25(OH)D) alone. This study aims to validate these findings by demonstrating that VMR is more strongly correlated with parathyroid hormone (PTH) levels than 25(OH)D and 24,25-dihydroxyvitamin D (24,25(OH)2D). In addition, the study investigates VMR as a more effective predictor of mortality than 25(OH)D and 24,25(OH)2D. Methods: The SarcoPhAge cohort is a Belgian cohort of community-dwelling older adults. Levels of 25(OH)D and 24,25(OH)2D were measured in 204 serum samples collected at the second year of follow-up using liquid chromatography–tandem mass spectrometry (LC–MS/MS), and VMR was calculated using the formula: VMR = (24,25(OH)D/25(OH)D) × 100. Vitamin D deficiency cut-offs were defined at 25(OH)D < 20 ng/mL, 24,25(OH)2D < 1.2 ng/mL, or VMR < 4% according to previously proposed cut-offs. Participants were followed for up to 9 years. Results: A total of 35 individuals (17.2%) had 25(OH)D < 20 ng/mL, 40 individuals (19.6%) had 24,25(OH)2D < 1.2 ng/mL, and 14 individuals (7.0%) had VMR < 4%. All three markers, 25(OH)D, 24,25(OH)2D, and VMR, were independently associated with PTH levels, with VMR showing the strongest correlation (rho: −0.292; p < 0.0001). When categorized into quartiles, only 24,25(OH)2D and VMR showed significant increases in PTH levels across quartiles (p = 0.002 and p < 0.0001, respectively). When cut-offs for low vitamin D status were applied, patients with low VMR had the highest rate of all-cause mortality. However, in a Cox proportional hazard regression model, both low VMR profile and low 25(OH)D profile were risk factors for all-cause mortality. Conclusions: This study confirms that VMR is an efficient biomarker for assessing functional vitamin D deficiency.