Vitamin D levels in systemic sclerosis patients: a meta-analysis

Area of Science:

• Endocrinology
• Rheumatology
• Nutritional Science

Background:

• Systemic sclerosis (SSc) is an autoimmune disease characterized by fibrosis and vascular abnormalities.
• Vitamin D plays a crucial role in immune function and bone metabolism, and its deficiency is implicated in various autoimmune conditions.

Purpose of the Study:

• To meta-analyze the association between vitamin D levels and systemic sclerosis.
• To compare vitamin D levels between SSc patients and healthy controls.
• To investigate differences in vitamin D levels between diffused- and limited-type SSc and their correlation with clinical manifestations.

Main Methods:

• A comprehensive literature search was conducted up to June 12, 2017.
• Pooled standardized mean difference (SMD) was calculated to compare vitamin D levels.
• Pooled risk ratios (RRs) with 95% confidence intervals (CIs) assessed the impact of vitamin D on clinical characteristics.

Main Results:

• Six studies involving 554 SSc patients and 321 controls revealed significantly lower vitamin D levels in SSc patients (SMD = -8.72 ng/mL).
• Diffused-type SSc patients had lower vitamin D levels compared to limited-type SSc patients (SMD = -4.71 ng/mL).
• No significant association was found between vitamin D levels and SSc severity markers like Rodnan score, pulmonary pressure, gastrointestinal ulcers, or pulmonary involvement.

Conclusions:

• Systemic sclerosis patients exhibit reduced vitamin D levels compared to healthy controls.
• Vitamin D deficiency is more pronounced in diffused-type SSc.
• The extent of vitamin D deficit does not correlate with the severity of clinical features in SSc, suggesting it may not be a primary driver of disease progression.