Exposure source in 30D prior to onset of illness:Type:Pt:^Patient:Nom
exposure source in 30d prior to onset of illness:type:pt:^patient:nom
Exposure source in 30D prior to onset of illness:Type:To identify measures at a point in time:^Patient:Nominal
exposure source in 30d prior to onset of illness:type:to identify measures at a point in time:^patient:nominal