TABLE 2.

Studies Investigating an Association Between Decreased Vitamin D Levels and Osteoarthritis (OA)

Authors	Study Design	Sample	Vitamin D Serum Level Measurements	Finding
Bassiouni et al9	Prospective cohort	50 patients with and without knee OA were observed over a 12-month period	Vitamin D deficiency <10 ng/mL Vitamin D insufficiency = 10.1-20.0 ng/mL Vitamin D sufficient ≥20 ng/mL	Vitamin D levels were significantly decreased in the patients with knee OA. Medial meniscal deterioration was seen in patients with low vitamin D levels, suggesting that vitamin D deficiency may play a role in the progression of medial compartment knee OA
Veronese et al49	Cross- sectional	2756 patients were evaluated for OA pain	Quintile 1: ≤53 nmol/L Quintile 2: >53 and ≤79 nmol/L Quintile 3: >79 and ≤103 nmol/L Quintile 4: >103 and ≤143 nmol/L Quintile 5: >143 nmol/L	For the knee, low vitamin D levels were associated with the presence of OA. Cumulatively, in all women, the presence of pain in the sample as a whole, low 25-hydroxyvitamin D levels were positively correlated with the severity of OA and with OA-related pain, particularly when the hand and hip are involved
Jansen and Haddad24	Cross- sectional	139 elderly patients with advanced knee OA awaiting surgery had serum vitamin D levels measured	Vitamin D deficiency <40 nmol/L Vitamin D sufficient ≥40 nmol/L	24% of patients were found to have vitamin D deficiency
Konstari et al27	Prospective cohort	5274 Finnish patients who did not have knee or hip OA at baseline had serum vitamin D levels measured. Serum vitamin D levels were measured 10 years later	Quartile 1: ≤33 nmol/L Quartile 2: ≥34 and ≤42 nmol/L Quartile 3: ≥43 and ≤54 nmol/L Quartile 4: ≥55 and ≤134 nmol/L	Low serum vitamin D concentration did not predict increased incidence of knee and hip OA