AbstractObjectiveThe aim of the present study was to investigate vitamin D status among female out-patients in Saudi Arabia during the summer and winter seasons.DesignData were retrospectively collected using medical record abstraction.SettingA multidisciplinary hospital in Riyadh between January and December 2009.SubjectsSaudi females (age ≥19 years;n1556) attending out-patient clinics for various complaints comprised the studied population. The population was subdivided into two groups depending on the date of their visit where blood samples were collected: summer (n659) and winter groups (n897). The summer group was further subdivided into premenopausal (age 19–49 years;n425) and postmenopausal subgroups (age ≥50 years;n234). Similarly, the winter group was subdivided into premenopausal (n543) and postmenopausal subgroups (n354). Serum levels of 25-hydroxyvitamin D (25(OH)D) were measured using HPLC.ResultsThe prevalence of vitamin D deficiency (25(OH)D <50 nmol/l) was high in both premenopausal and postmenopausal groups (80 % and 68 %, respectively) during the summer, as well as during the winter (85 % and 76 %, respectively).ConclusionsA high prevalence of vitamin D deficiency among Saudi female out-patients was observed throughout the year despite the routine supplementation with 10–20 μg vitamin D3for postmenopausal women. Clinicians should seriously consider determining the vitamin D status of Saudi females routinely and prescribing them proper supplementation.

Vitamin D binding protein (DBP) is a major carrier protein for the vitamin D metabolites, but may also play an important role in osteoclast differentiation. Polymorphisms of the DBP gene have been reported, including (TAAA)(n)-Alu repeat polymorphisms downstream of intron 8. We have examined the relationship between polymorphisms of the DBP gene and bone mineral density (BMD) and vertebral fractures in a group of 26 men with vertebral fractures but no underlying secondary cause of osteoporosis (median age 64, ages 27-72 years) and 21 male control subjects (median age 65, ages 40-77 years). There was no apparent effect of DBP phenotype on BMD, but there was a relationship between certain genotypes of (TAAA)(n)-Alu repeats and reduced BMD and vertebral fracture. Lumbar spine and femoral neck BMD were significantly lower in men with 10/8 genotype than 10/10 genotype (P < 0.05). Furthermore, the predominant genotype in men with vertebral fractures was 10/8, whereas the most common genotype in control subjects was 10/10 (odds ratio 56; 95% confidence interval 7-445). Plasma DBP was higher in men with 10/8 genotype than those with 10/10 genotype (P < 0.05), and patients with vertebral fractures were found to have higher levels than control subjects (P < 0.0005). Although our study is small because of the relative rarity of idiopathic osteoporosis in men, the results suggest that (TAAA)(n)-Alu polymorphism may have an important effect on plasma levels of DBP, bone density and fracture risk in men.

The study shows that in this population of healthy men there is a weak association between lumbar spine bone mineral density and FokI restriction fragment length polymorphism at the translation initiation site of the vitamin D receptor gene.

CONTEXT:Osteoporosis is a polygenic, multifactorial disease that is characterized by demineralization of bone, and thus presented with decreasing bone mineral mass. Vitamin D receptor (VDR) gene polymorphisms in the 3’-end region (as determined by the enzymes BsmI and ApaI) have been inconsistently associated with bone mineral mass. Another important VDR start codon polymorphism (as determined by the enzyme FokI) has been found to be related to adult bone mineral density (BMD) in pre-and post-menopausal American women.AIMS:This study aims to investigate the prevalence of the FokI VDR gene polymorphism in Jordanian perimenopausal women and study its relationship with bone mineral density.MATERIALS AND METHODS:DNA was isolated from 90 controls (Mean age = 50.41 ± 1.29 y), and 120 patients with symptomatic vertebral fractures (Mean age = 49.14 ± 3.19 y). Restriction Fragment Length Polymorphism (RFLP) analysis of FokI was performed on DNA samples.STATISTICAL ANALYSIS:Data was analyzed using SPSS v19 and Microsoft Excel 2007.RESULTS:The results showed that in controls, the FF (−0.70 ± 0.51) genotype is associated with high lumbar spine BMD Z-score as compared to Ff (−1.25 ± 0.26) and ff (−1.66 ± 0.47) genotypes (P = 0.0095). In patients, the ff genotype was associated with lower lumbar spine BMD in T-score (−2.31 ± 0.17) and Z-score (−1.56 ± 0.09) genotypes (P = 0.031). No significant association was seen in the femoral neck BMD.CONCLUSION:FokI polymorphism may be associated with low BMD in our studied population; however, further studies including other polymorphisms and large sample number are needed.

No abstract