Vitamin D Improves Outcomes of Early Knee Osteoarthritis: Study

The role of vitamin D in the origin and development of the disease is not clear, although it could have important implications for diagnosis and treatment. Therefore, researchers of Spain conducted a study to evaluate the association of serum concentrations of vitamin D with knee EOA. They further determined the association of serum concentrations of PTH with knee EOA and the relationship between vitamin D deficiency, parathyroid hormone (PTH) level, and pain intensity, disability, psychological and functional variables in patients with knee EOA.

The researchers conducted a cross-sectional study in which they included a total of 96 patients, among which 48 with EOA and 48 matched controls. The researchers evaluated serum 25(OH)D and PTH levels. They also evaluated the physical and psychological variables to establish their relationship with vitamin D levels. They used the visual analogue scale to measure the pain intensity. The Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) questionnaire is self-administered was used to assess the OA disability. The researchers also employed the five-Time Sit to Stand test to assess functional capacity. In addition, psychological and social variables were measured to establish their relationship with vitamin D levels.

Key findings of the study:

• Upon analysis, the researchers found that patients with EOA showed lower levels of vitamin D (22.3 ± 7.3 ng/mL) in comparison to matched controls (29.31 ± 9.2 ng/mL).
• They noted a significant higher number (Chi-squared = 8.525; p = 0.004) of patients with EOA had deficiency levels (<20 ng/mL) compared to the control group.
• They found that the patients with lower vitamin D levels had higher levels of pain intensity, disability, and anxiety, as well as poorer values for sit-to-stand, walking speed, and social participation.
• Upon correlation analysis, they observed a relationship between serum 25(OH)D, PTH and pain intensity, and social participation.

The authors concluded, "The presence of vitamin D deficiency among patients with knee EOA is significantly related to a higher level of pain intensity, disability, anxiety and depressive symptoms, lower social participation, and physical performance. Lower PTH level is associated with higher pain intensity and lower social participation. These results highlight the relevance of vitamin D in the early diagnosis and prevention of EOA.".

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DOI: https://doi.org/10.3390/nu13114035