An integrated circuit device includes a plurality of pillars protruding from a substrate in a first direction. Each of the pillars includes source/drain regions in opposite ends thereof and a channel region extending between the source/drain regions. A plurality of conductive bit lines extends on the substrate adjacent the pillars in a second direction substantially perpendicular to the first direction. A plurality of conductive shield lines extends on the substrate in the second direction such that each of the shield lines extends between adjacent ones of the bit lines. Related fabrication methods are also discussed.