Participants were observed taking a walk over a short distance at their usual pace, starting from a standing position, and an examiner timed the task by using a handheld stopwatch that measured to the nearest hundredth of a second. The walking distance ranged from 3 to 5 m according to different study sites. The gait speed was calculated as the walking distance (m) divided by time (s). The investigators examined the distribution of the gait speed stratified according to the sex-specific median height. Participants with a gait speed in the lowest 20% of the sex- and height-specific distributions were considered to have low gait speed.