Vitamin D binding protein genotype is associated with serum 25-hydroxyvitamin D and PTH concentrations, as well as bone health in children and adolescents in Finland

• Published in: PloS one 2014-01, Vol.9 (1), p.e87292
• Main Authors: Pekkinen, Minna, Saarnio, Elisa, Viljakainen, Heli T, Kokkonen, Elina, Jakobsen, Jette, Cashman, Kevin, Mäkitie, Outi, Lamberg-Allardt, Christel
• Format: Article
• Language: English
• Subjects: 25-Hydroxyvitamin D; Adolescent; Adolescents; Age; Alleles; Analysis; Binding; Biology; Biomedical materials; Bone and Bones; Bone density; Bone Density - genetics; Bone mass; Bone mineral content; Bone mineral density; Calcium; Calcium homeostasis; Calcium, Dietary - metabolism; Child; Child health; Children; Computed tomography; Diet; Dietary intake; Dual energy X-ray absorptiometry; Environmental science; Exercise; Female; Finland; Food; Fractures; Gc gene; Gene expression; Gene polymorphism; Genetic aspects; Genetic diversity; Genotype; Genotypes; Genotyping; Hip; Homeostasis; Hospitals; Humans; Male; Medicin och hälsovetenskap; Medicine; Mens health; Metabolites; Mineralization; Nutrition; Osteoporosis; Parathyroid; Parathyroid hormone; Parathyroid Hormone - blood; Parathyroid Hormone - genetics; Parathyroid Hormone - metabolism; Parathyroid hormones; Polymorphism; Polymorphism, Single Nucleotide - genetics; Protein binding; Proteins; Regression analysis; Single nucleotide polymorphisms; Single-nucleotide polymorphism; Spine; Spine (lumbar); Studies; Surgical implants; Teenagers; Urine; Vitamin D; Vitamin D - analogs & derivatives; Vitamin D - blood; Vitamin D - genetics; Vitamin D - metabolism; Vitamin D-Binding Protein - genetics; Vitamin D-Binding Protein - metabolism; Vitamin deficiency; White people
• ISSN: 1932-6203; 1932-6203
• DOI: 10.1371/journal.pone.0087292

Vitamin D binding protein (DBP)/group-specific component (Gc), correlates positively with serum vitamin D metabolites, and phenotype influences serum 25-hydroxyvitamin D (S-25(OH)D) concentration. The protein isoform has been associated with decreased bone mineral density (BMD) and increased fracture risk. We examined the role of GC genotypes in S-25(OH)D status and BMD in 231 Finnish children and adolescents aged 7-19 yr. BMD was measured with DXA from lumbar spine (LS), total hip, and whole body, and for 175 subjects, radial volumetric BMD was measured with pQCT. Background characteristic and total dietary intakes of vitamin D and calcium were collected. The concentrations of 25(OH)D, parathyroid hormone (PTH), calcium and other markers of calcium homeostasis were determined from blood and urine. Genotyping was based on single-nucleotide polymorphism (rs4588) in the GC gene. The genotype distribution was: GC 1/1 68%, GC 1/2 26% and GC 2/2 6%. A significant difference emerged in 25(OH)D and PTH concentrations between the genotypes, (p = 0.001 and 0.028 respectively, ANCOVA). There was also a linear trend in: Gc 2/2 had the lowest 25(OH)D and PTH concentrations (p = 0.025 and 0.012, respectively). Total hip bone mineral content was associated with GC genotype (BMC) (p = 0.05, ANCOVA) in boys. In regression analysis, after adjusting for relevant covariates, GC genotype was associated with LS BMC and strength and strain index (SSI) Z-score in both genders, and LS BMD in boys. In conclusion, the present study demonstrates the association between GC genotypes and S-25(OH)D and PTH concentrations. The results show the influence of DBP genetic variation on bone mass accrual in adolescence.