ABSTRACT
<p><b>OBJECTIVE</b>To investigate the effect of interleukin-6 (IL-6) and calcium sensing receptor (CASR) gene polymorphisms on bone mass accrual in Chinese adolescent girls.</p><p><b>METHODS</b>A total of 228 premenarche Chinese girls (9-11.5 years) were recruited for a 2-year study. Bone mineral densities (BMD) and Bone mineral contents (BMC) in the total body, total left hip including femoral neck, trochanter, intertrochanter and Ward's triangle area, and lumbar spine (L1-L4) were measured by DEXA. The -634C/G polymorphism of IL-6 gene was detected by PCR-restriction fragment length polymorphism and A986S polymorphism of CASR gene was detected by allele-special mutagenically separated amplication-PCR.</p><p><b>RESULTS</b>There were 176 available subjects when the 2-year study was completed. The -634C/G polymorphism of IL-6 gene and A986S polymorphism of CASR gene were significantly associated with bone mass accrual after adjusting the potential confounding factors. Girls with CC genotype of IL-6 -634G/C gene had higher percentage of increase in BMD of total body (P= 0.027) and femoral trochanter (P= 0.028) than those with CG+ GG genotypes. Girls with AA genotype of CASR gene had greater percentage of increase in L1-L4 lumbar spine BMC (P= 0.022) and Ward's triangle area BMD (P= 0.049) than their AS+ SS counterparts. Subjects with G allele of IL-6 gene in combination with S allele of CASR gene had less increase in BMC of femoral neck and L1-L4 lumbar spine.</p><p><b>CONCLUSION</b>Adolescent girls carrying the G allele of IL-6 gene at -634C/G and S allele of CASR gene at A986S could potentially be the risk population of lower bone mass accrual.</p>
Subject(s)
Child , Female , Humans , Alleles , Bone Density , Genetics , Genotype , Interleukin-6 , Genetics , Polymerase Chain Reaction , Polymorphism, Genetic , Genetics , Receptors, Calcium-Sensing , GeneticsABSTRACT
<p><b>OBJECTIVE</b>To investigate the association between the polymorphism of vitamin D receptor (VDR) gene start codon (Fok I) and bone mass accrual, and assessing if such an association could be modified by physical activity in Chinese adolescent girls.</p><p><b>METHODS</b>A total of 228 premenrche Chinese girls (9-11.5-years-old) were recruited for 2-year study. Bone mineral densities (BMD) at the total body, total left hip (including femoral neck, trochanter, intertrochanteric and Ward's triangle area) and lumbar spine (L1-L4) were measured by dual energy X-ray absorptiometry. The Fok I polymorphism of VDR gene was detected with PCR-RFLP.</p><p><b>RESULTS</b>There remained 176 available subjects in our cohort when 2-year study was completed. No significant association was observed between Fok I polymorphism of VDR gene and percentage change in BMD at all sites. Girls with FF genotype had lower percentage change in total left hip BMD (THBMD) and femoral neck BMD (FNBMD) than girls with Ff + ff genotype only in low physical activity(< 1197 kJ/d), and physical activity was associated with percentage change in THBMD and FNBMD only in FF genotype group.</p><p><b>CONCLUSION</b>The Fok I polymorphism of VDR gene should have significant interaction effect with physical activity on bone mass accrual in Chinese adolescent girls. Girls with FF genotype in low physical activity would be the potential risk population for low bone mass accrual, and high physical activity would be of benefit to gain higher bone mass accrual for girls with FF genotype.</p>