Year-round vitamin D deficiency among Saudi female out-patients.

OBJECTIVE: The aim of the present study was to investigate vitamin D status among female out-patients in Saudi Arabia during the summer and winter seasons. DESIGN: Data were retrospectively collected using medical record abstraction. SETTING: A multidisciplinary hospital in Riyadh between January and December 2009. SUBJECTS: Saudi females (age ≥19 years; n 1556) 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 (n 659) and winter groups (n 897). The summer group was further subdivided into premenopausal (age 19-49 years; n 425) and postmenopausal subgroups (age ≥50 years; n 234). Similarly, the winter group was subdivided into premenopausal (n 543) and postmenopausal subgroups (n 354). Serum levels of 25-hydroxyvitamin D (25(OH)D) were measured using HPLC. RESULTS: The 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). CONCLUSIONS: A 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 D3 for postmenopausal women. Clinicians should seriously consider determining the vitamin D status of Saudi females routinely and prescribing them proper supplementation.

The effect of FokI vitamin D receptor polymorphism on bone mineral density in Jordanian perimenopausal women.

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.

Possible association of combined vitamin D receptor and estrogen receptor genotypes and low bone mineral density in Jordanian postmenopausal women.

The genetics of osteoporosis has been extensively studied over the last 20 years. Many of the studies have been aimed at identifying possible risk factors and possible association with low bone mineral density (BMD). Vitamin D receptor (VDR) and estrogen receptor (ER) gene polymorphisms were the first to be studied. Some studies have shown a possible association for individual VDR and ER or combined VDR and ER genotypes in some populations, and others showed lack of such an association. This study is aiming at identification of a possible association with low BMD in Jordanian postmenopausal women. We used restriction fragment length polymorphisms (RFLPs) to study four polymorphisms in the VDR gene and two polymorphisms in the ER gene. Our sample was composed of 100 normal controls and 120 samples from patients with symptomatic vertebral fractures. The results showed a possible association of the ppxx genotype with low BMD in controls and patients and an association of the AaBbTT genotype with high BMD in control subjects. The AABBTT, AABBTTFF, and AABBTTFFPPXX genotypes showed a possible association with low BMD in patients. Further studies are needed to confirm the last finding since it could be an important predictor of low BMD in the Jordanian population.