The Association of Vitamin D, Growth/Differentiation Factor 5 (GDF-5) Gene Polymorphism, and Serum GDF-5 Protein in Obese Patients With Knee Osteoarthritis

Background and objective Osteoarthritis (OA) is influenced by genetics and environmental factors, including vitamin D deficiency. This study aimed to investigate the association between vitamin D levels, growth/differentiation factor 5 (GDF-5) gene polymorphism, and serum GDF-5 in obese females with knee OA (KOA) in Saudi Arabia. Methodology The study enrolled 60 female patients with OA and 60 healthy females as controls. Blood samples were collected to evaluate the GDF-5 T>C (rs143383) polymorphism using polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP). The study also measured serum levels of vitamin D, GDF-5, calcium, uric acid, lipid profiles, C-reactive protein (CRP), and erythrocyte sedimentation rate (ESR), and assessed the participants' BMI. Results The study demonstrated that KOA patients had reduced vitamin D levels in their bodies, along with GDF-5 and calcium. However, they had increased levels of uric acid, lipid profile, CRP, and ESR. Strong correlations were observed between vitamin D levels, lipid profile, CRP, ESR, BMI, GDF-5 gene polymorphisms, and GDF-5 protein. Genotype analysis showed KOA patients had TT (30%), TC (50%), and CC (20%) genotypes, while the control group showed TT (22%), TC (35%), and CC (43%) genotypes. Allele analysis revealed a noteworthy association between the T allele and KOA; the C allele was more common in the control group. Conclusions The study findings provide valuable insights into the association of vitamin D levels with GDF-5 T>C (rs143383) polymorphism, GDF-5 protein, and inflammatory markers in obese Saudi females with KOA. These findings suggest potential associations between these biomarkers and the pathogenesis or progression of KOA.