Low vitamin D serum levels in diffuse systemic sclerosis: a correlation with worst quality of life and severe capillaroscopic findings

Objective: The aim of this study was to analyze the correlation of vitamin D levels with clinical parameters, bone mineral density (BMD), quality of life (QoL) and nailfold capillaroscopy (NC) in patients with diffuse systemic sclerosis (SSc).

Methods: Thirty-eight female patients with diffuse SSc were analyzed regarding 25-hydroxyvitamin D (25OHD) serum levels. At inclusion, organ involvement, autoantibodies, modified Rodnan skin score (mRSS), Medsger Disease Severity Index (MDSI), body mass index (BMI), BMD, NC, Short-Form-36 Questionnaire (SF-36), and Health Assessment Questionnaire (HAQ), were performed through a standardized interview, physical examination and electronic chart review.

Results: Mean 25OHD serum level was 20.66±8.20ng/mL. Eleven percent of the patients had 25OHD levels ≤10ng/mL, 50% ≤20ng/mL and 87% ≤30ng/mL. Vitamin D serum levels were positively correlated with BMI (r=0.338, p=0.038), BMD-total femur (r=0.340, p=0.037), BMD-femoral neck (r=0.384, p=0.017), SF-36-Vitality (r=0.385, p=0.017), SF-36-Social Function (r=0.320, p=0.050), SF-36-Emotional Role (r=0.321, p=0.049) and SF-36-Mental Health (r=0.531, p=0.0006) and were negatively correlated with HAQ-Reach (r=-0.328, p=0.044) and HAQ-Grip Strength (r=-0.331, p=0.042). A negative correlation with NC-diffuse devascularization (p=0.029) and NC-avascular area (p=0.033) was also observed.

Conclusion: The present study provides novel evidence demonstrating that low levels of 25OHD have a negative impact in diffuse SSc QoL and further studies are needed to define whether vitamin D supplementation can improve health related QoL in these patients. The additional observation of a correlation with severe NC alterations suggests a possible role of 25OHD in the underlying SSc vascular involvement.