"dbGAP Variable","dbGAP Study","dbGAP Variable Description" phv00168366,"The Genomics and Randomized Trials Network (GARNET) Vitamin Intervention Stroke Prevention (VISP) trial","Are you taking any of the following supplements on a regular basis? Other supplement? (DSF) During the past year, did you take any of the following supplements on a regular basis? Other supplement? (FDS)"