Vitamin D Supplements and Total Cancer Incidence and Mortality: a Meta-analysis of randomized controlled trials
A partir d'une revue systématique de la littérature publiée jusqu'en novembre 2018 (10 essais randomisés, 6 547 cas, durée de suivi : 3-10 ans), cette méta-analyse évalue l'association entre une supplémentation en vitamine D, le risque de cancer et la mortalité spécifique
Previous meta-analyses of randomized controlled trials (RCTs) of vitamin D supplementation and total cancer incidence and mortality found inconsistent results, and most included trials administered generally low doses of vitamin D (≤ 1100 IU/day). We updated the meta-analysis by incorporating recent RCTs that have tested higher doses of vitamin D supplements.PubMed and Embase were searched from the inception to November, 2018. Summary relative risks (RRs) and 95% confidence intervals (CIs) were estimated using a random-effects model.For total cancer incidence, 10 trials were included (6,547 cases; 3-10 years of follow-up; 54-135 nmol/L of attained levels of circulating 25(OH)vitamin D [25(OH)D] in the intervention group). The summary RR was 0.98 (95% CI, 0.93 to 1.03; P=.42; I2=0%). The results remained null across subgroups tested, including even when attained 25(OH)D levels exceeded 100 nmol/L (RR, 0.95; 95% CI, 0.83 to 1.09; P=.48; I2=26%). For total cancer mortality, 5 trials were included (1,591 deaths; 3-10 years of follow-up; 54-135 nmol/L of attained levels of circulating 25(OH)D in the intervention group). The summary RR was 0.87 (95% CI, 0.79 to 0.96; P=.005; I2=0%), which was largely attributable to interventions with daily dosing (as opposed to infrequent bolus dosing). No statistically significant heterogeneity was observed by attained levels of circulating 25(OH)D (Pheterogeneity=.83), with RR being 0.88 (95% CI, 0.78 to 0.98; P=.02; I2=0%) for ≤ 100 nmol/L and 0.85 (95% CI, 0.70-1.03; P=.11; I2=0%) for > 100 nmol/L.In an updated meta-analysis of RCTs, vitamin D supplementation significantly reduced total cancer mortality but did not reduce total cancer incidence.
Annals of Oncology 2019