The status of biochemical parameters in varying degrees of vitamin D deficiency

Abstract

Vitamin D (Vit D) is an essential element for the regulation of serum calcium, phosphate, and alkaline phosphatase (Alk Ph). Because the Vit D serum level is not usually measured directly, Vit D deficiency is diagnosed indirectly by changes in serum calcium, phosphate, and Alk Ph leves. The current study assessed the status of these biochemical parameters in subjects with different degrees of Vit D deficiency. We selected 1,210 subjects, between 20 and 69 years old, randomly from the Tehran population. Subjects with diseases or medications that modified bone metabolism were excluded from the study. Serum 25(OH) D, calcium, phosphate, Alk Ph, and parathyroid hormone (PTH) levels were measured and the status of these biochemical parameters was compared in subjects with different degrees of Vit D deficiency. Vit D deficiency was diagnosed in 79.6% of the subjects. Different degrees of Vit D deficiency were classified as follows: group 1, severe; group 2, moderate; and group 3, mild. Serum PTH levels in the Vit D-deficient groups were significantly higher than that in group 4 (normal Vit D). Serum calcium and phosphate levels in groups 1 and 2 were significantly lower than those in groups 3 and 4. No significant difference was seen in serum Alk Ph in the groups with different degrees of Vit D deficiency. The sensivity for at least one biochemical variable (calcium, phosphorus, or Alk Ph) for the detection of severe, moderate, and mild Vit D deficiency was 24.2%, 13.8%, and 6%, respectively. When the serum 25(OH) D level was reduced to less than 25 nmol/l (groups 1 and 2), the effects of Vit D deficiency on calcium and phosphate levels were obvious. Therefore, the usual biochemical parameters (calcium, phosphate, Alk Ph) alone do not have sufficient sensitivity to detect mild deficiency of Vit D.

Hypovitaminosis D in a healthy female population, aged from 40 to 85 years, in the west of Ireland

“…It has been demonstrated that calcium, inorganic phosphate and alkaline phosphatase levels alone do not identify 25(OH)D depletion except when 25(OH)D is deficient (\25 nmol/L) [27], although our study does not entirely concur with this. We found a significant correlation between 25(OH)D and alkaline phosphatase, in that 15% of subjects in our study had elevated alkaline phosphatase concentrations and, of these, 57% had insufficient 25(OH)D. In general, patients with alkaline phosphatase concentrations greater than 120 IU/L, in the absence of liver or other bony diseases, are likely to have low 25(OH)D concentrations.…”

Can vitamin D status be assessed by serum 25OHD in children?

“…Only four children had PTH levels above the normal reference values, two of them were infants and two were in the 2-5 years' group. These four children had 25OHD concentrations greater than 20 ng/ml and did not present clinical or biochemical data of secondary hyperparathyroidism [42].…”

Association of obesity with vitamin D deficiency and the clinical implications

“…Vitamin D level ≤12.5 nmols/l was classified as severe vitamin D deficiency, 12.5-25 nmols/l was classified as moderate Vitamin deficiency and >25 nmols/l was classified as mild vitamin D deficiency. 16 After measuring the height in cm and weight in kg, Body Mass Index (BMI) was calculated. The weight was measured with light clothing and no shoes.…”