Trial sequential meta-analysis.
Link: http://www.thelancet.com/journals/landia/article/PIIS2213-8587%2813%2970212-2/abstract
From interpretation:
"Our findings suggest that vitamin D supplementation with or without calcium does not reduce skeletal or non-skeletal outcomes in unselected community-dwelling individuals by more than 15%. Future trials with similar designs are unlikely to alter these conclusions."