Background & aims: Inflammation plays a key role in tumor development and progression. Vitamin D has potential tumor suppressing effects through modulation of inflammatory processes. The aim of this systematic review and meta-analysis of randomized controlled trials (RCTs) was to summarize and evaluate the effects of vitamin D3 supplementation (VID3S) on serum inflammatory biomarkers among patients with cancer or pre-cancerous lesions.
Methods: We searched PubMed, Web of Science and Cochrane databases until November 2022. The effects of VID3S were estimated from pooled standardized mean differences (SMDs) with their 95% confidence intervals (CIs) for inflammatory biomarker follow-up levels between intervention and control groups.
Results: Meta-analysis of eight RCTs (total of 592 patients with cancer or pre-cancerous conditions) showed that VID3S significantly lowered levels of serum tumor necrosis factor (TNF)-α (SMD [95%CI]: -1.65 [-3.07; -0.24]). VID3S also resulted in statistically non-significantly lower serum levels of interleukin (IL)-6 (SMD [95%CI]: -0.83, [-1.78; 0.13]) and C-reactive protein (CRP) (SMD [95%CI]: -0.09, [-0.35; 0.16]), whereas IL-10 levels were unaltered (SMD [95%CI]: -0.00, [-0.50; 0.49]).
Conclusion: Our study shows evidence of a significant reduction of TNF-α levels by VID3S for patients with cancer or precancerous lesions. Patients with cancer or precancerous lesions may benefit from personalized VID3S in suppressing tumour-promoting inflammatory response.
Prospero registration number: CRD42022295694.
Keywords: Biomarker; Cancer; Inflammation; Precancer; Vitamin D3 supplement.
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