VDR and diabetes mellitus: The D2d trial was conducted from October 1, 2013, to November 28, 2018, with statistical analysis performed from January 3 to November 30, 2025.<h4>Exposures</h4>Receipt of 4000 IU/d of vitamin D3 vs placebo for a median of 2.5 years (IQR, 1.8-3.5 years).<h4>Main outcomes and measures</h4>In the discovery phase analysis among 1903 participants with available data, the risk of diabetes across different intratrial mean 25(OH)D levels in association with the VDR polymorphisms was examined.