VITAMIN-D STATUS AND CALCIUM-REGULATING HORMONES IN SAUDIS - A PROSPECTIVE-STUDY

Objective: To evaluate the nutritional status of vitamin D in relation to calcium-regulating hormones and related minerals. Methods: A prosp ective study was conducted of 451 Saudi subjects (172 males, 279 femal es) living in the Jeddah area. Serum calcidiol and calcitriol concentr ations were measured together with concentrations of serum intact-para thyroid hormone (PTH), calcitonin, vitamin D binding protein (DBP), al kaline phosphatase, calcium, phosphate and magnesium in the studied Sa udi subjects. Results: The overall means for serum calcidiol and calci triol were 48.15 nmol/l and 82.55 nmol/l, respectively. No significant difference was observed between serum calcidiol and calcitriol values among males and females studied. Subclinical vitamin D deficiency (se rum calcidiol < 20 nmol/l) was observed in 23 males and 46 females giv ing an overall rate of 15.3%. Severe biochemical vitamin D deficiency (serum calcidiol <12.5 nmol/l) was observed in three males (1.74%) and eight females (2.4%), respectively. Serum calcidiol correlated with s erum calcitriol (r=0.773, p<0.001); calcium (r=0.227, p<0.001); intact -PTH (r=-0.219, p<0.001) and alkaline phosphatase (r=-0.327, p<0.001), respectively. Whereas, serum calcitriol correlated with serum calcium (r=0.113, p<0.01); and alkaline phosphatase (r=-0.307, p<0.001), resp ectively. Stepwise multiple-regression analysis showed that calcitriol and phosphate contributed significantly to the variation in serum cal cidiol with minor contributions from intact-PTH, calcitonin and calciu m. Conclusion: These observations provide detailed information on the nutritional status of vitamin D in the local population in relation to calcium-regulating hormones and minerals and show that 15.3% of the s tudied population exhibited subclinical vitamin D deficiency.