Effect of vitamin D supplementation on circulating level of autophagosome protein LC3A, inflammation, and physical performance in knee osteoarthritis

The U-shaped correlation between serum VD concentration and systemic immune-inflammatory index: results from the NHANES database prospective cohort study

BACKGROUND

Vitamin D (VD) plays a critical role in regulating systemic inflammation, but its correlation with the systemic immune-inflammatory index (SII) remains unclear. This study aimed to explore the relationship between serum VD concentration, dietary VD intake, and SII using data from the National Health and Nutrition Examination Survey (NHANES).

METHODS

Data from NHANES 2007-2018 and NHANES 2007-2020 were analyzed for serum VD levels and dietary VD intake, respectively. Restricted cubic splines (RCS) and logistic regression were used to assess associations between VD and SII. Mediation analysis was conducted to evaluate the role of SII in VD-related disease outcomes and mortality.

RESULTS

Serum VD concentration exhibited a U-shaped correlation with SII (P-overall = 0.005; P-non-linear = 0.002). Severe VD deficiency significantly elevated SII levels compared to insufficiency or sufficiency groups. No association was observed between dietary VD intake and SII. Mediation analysis revealed that SII mediated the effects of VD on all-cause and cardiovascular disease-related mortality, but not on cancer, hypertension, or diabetes development.

CONCLUSION

A U-shaped relationship exists between serum VD and SII, with VD supplementation potentially reducing systemic inflammation and improving cardiovascular outcomes. Future studies should explore VD's role in systemic inflammation and its clinical implications.

Current Evidence on and Clinical Implications of Vitamin D Levels in Pain and Functional Management of Knee Osteoarthritis: A Systematic Review

BACKGROUND

Osteoarthritis is a common chronic disease that affects quality of life and increases public health costs. Knee osteoarthritis is a frequent form, marked by joint degeneration, pain, stiffness, and functional restrictions. Factors such as age, genetics, joint injuries, obesity, and vitamin D deficiency can affect knee osteoarthritis progression. While the exact link between vitamin D and osteoarthritis is still being studied, recent research indicates that low vitamin D levels might influence the articular cartilage's structure and function, potentially accelerating osteoarthritis. This review aims to analyze the last decade of research on vitamin D's role in osteoarthritis.

METHODS

A systematic review of the literature was conducted in accordance with the PRISMA guidelines (Preferred Reporting Items for Systematic Reviews and Meta-Analyses). Relevant studies from the last ten years were included to evaluate the association between vitamin D levels and knee osteoarthritis. The inclusion criteria were studies examining the role of vitamin D in cartilage health and osteoarthritis progression and the potential clinical implications for disease management.

RESULTS

This review identified a variety of studies exploring the connection between vitamin D and osteoarthritis, with mixed findings.

CONCLUSIONS

The relationship between vitamin D and knee osteoarthritis remains inconclusive, highlighting the need for further research. An updated evaluation of the literature is crucial for osteoarthritis management strategies and to potentially include vitamin D supplementation in therapeutic protocols.

Effect of vitamin D supplementation on circulating level of autophagosome protein LC3A, inflammation, and physical performance in knee osteoarthritis

Aberrant autophagic activity is observed in osteoarthritic joints. Vitamin D was shown to alleviate not only osteoarthritis severity, but also autophagy process. However, the influence of vitamin D on autophagy in knee osteoarthritis (KOA) remains ambiguous. This study aimed to determine the effect of vitamin D2 on serum levels of autophagosome protein LC3A in patients with KOA and whether LC3A levels were correlated with serum 25-hydroxyvitamin D (25(OH)D) and clinical outcomes of patients with KOA. A total of 165 patients with KOA and 25 healthy controls were recruited. Vitamin D2 (ergocalciferol) was administered to patients with KOA at a weekly dosage of 40,000 IU. Serum LC3A, knee pain and functional scores, muscle strength, physical performance, and biochemical parameters were examined before and after 6 months of vitamin D2 supplementation. Serum LC3A levels were significantly higher in patients with KOA than healthy controls. In patients with KOA, vitamin D2 supplementation significantly decreased serum LC3A levels. Furthermore, baseline levels of serum LC3A were significantly associated with radiographic severity, pain and functional scores, total cholesterol, hs-CRP, IL-6, protein carbonyl, and serum 25(OH)D. After adjusting for established confounders, independent relationships among serum LC3A and radiographic severity, pain and functional scores, total cholesterol, hs-CRP, IL-6, protein carbonyl, and serum 25(OH)D were also observed. Vitamin D2 supplementation was shown to not only decrease serum levels of LC3A, inflammatory markers, as well as oxidative stress, but also improve muscle strength and physical performance in patients with KOA.