Association of polymorphisms in the vitamin D receptor promoter with idiopathic short stature

Growth, Dietary Intake, and Vitamin D Receptor (VDR) Promoter Genotype in Indonesian School-Age Children

Nutrition has been known as a predominant factor associated with stunting. However, some studies have discovered a genetic contribution in calcium absorption that will affect growth, known as the VDR gene. The aim of this study was to assess the association between VDR gene polymorphism and dietary intake towards height-for-age z-score (HAZ) of elementary school children in Malang District, East Java. This study analyzed the baseline of a randomized trial in East Java, Indonesia. School children aged 8–10 years old (n = 142) were included in this study. Energy, protein, calcium, and vitamin D intakes were obtained using 4-day 24-h dietary recalls. Two SNPs located in the promoter region of VDR gene were selected (rs11568820 and rs4516035) and analyzed using Real-Time PCR. The result showed a significant correlation between energy and protein intake with HAZ of the children (p = 0.030 and p = 0.016, respectively). The association between VDR gene and HAZ was not found (p > 0.05). Adjusted by other factors, protein intake was significantly correlated with HAZ (β = 0.034, 95% CI 0.015–0.052, p < 0.001, adj. R² = 0.089). The children in our study had a favorable VDR gene genotype, however the effect of VDR gene promoter activity might not be revealed due to very low vitamin D and calcium intake to stimulate intestinal calcium absorption which in turn affects HAZ.

Association between vitamin D receptor polymorphisms and osteoporosis in patients with COPD

BACKGROUND

Patients with COPD are at an increased risk of osteoporosis. Although many studies have addressed the relationship between the vitamin D receptor (VDR) polymorphisms and bone health, this relationship has not been fully investigated in patients with COPD. In this study, we investigated the association of VDR polymorphisms with bone mineral density (BMD) and other clinical parameters in patients with COPD.

PATIENTS AND METHODS

In total, 200 patients with COPD were included in this study. The VDR polymorphisms rs1544410 (A/G-BsmI), rs7975232 (A/C-ApaI), rs731236 (C/T-TaqI), and rs10735810 (C/T-FokI) were determined by Sanger sequencing using blood DNA samples. BMD of the lumbar vertebra and the femoral neck was measured by dual-energy X-ray absorptiometry. Other clinical parameters were also evaluated. Haplotype and multivariate analyses were also performed.

RESULTS

Sex, body mass index, steroid use, percentage of forced expiratory volume in 1 second (FEV1), alkaline phosphatase, and 25-hydroxyvitamin D significantly influenced the risk of osteoporosis. Patients with osteoporosis were more likely to carry the rs7975232 C allele compared to normal patients with BMD. Haplotypes GCT and GAT were related to osteoporosis. Patients without the haplotype GAT allele showed a significantly lower T-score at the femoral neck and an increased risk of osteoporosis (odds ratio [OR]= 2.78, 95% confidence interval [CI]= 1.20-6.48, P=0.018) compared with carriers in the dominant model.

CONCLUSION

Genetic variations in VDR are significantly associated with osteoporosis among patients with COPD. Further studies are required to confirm the role of the VDR polymorphisms in osteoporosis among patients with COPD.