 - HANDLS initially recruited 3,720 participants Phase I, visit 1. Given that only Phase II had in-depth data including biochemical indices and cognitive performance measures, 25OHD was available for 1,981 participants at baseline. The corresponding sample size for dietary and supplemental vitamin D were N2,177 and N2,159, respectively. Complete and reliable cognitive tests at each visit varied in sample size as well. Further, the final analytic sample was determined based on exposure and covariate non-missingness at baseline and outcome non-missingness at either visit. The final analytic sizes ranged between N1,231 and N1,803 with k1.5-1.9 observationparticipant. 