POSTURAL STABILITY OF WORKERS EXPOSED TO LEAD

Objective-To detect, with a computerised postural sway measurement sys tem, any significant deviation of postural sway parameters among lead workers compared with a control group. Methods-Postural stability was investigated with a computerised postural sway measurement system in 6 0 workers exposed to lead with a duration of exposure of 84 (range 3-3 66) months and 60 controls. Sway parameter data were collected with an Advanced Mechanical Technology computerised biomechanics platform sys tem. Results-The mean current blood lead concentration was 36.0 (range 6.4 to 64.5) mu g/dl for the exposed workers and 6.3 (range 3.1 to 10 .9) pg/dl for the 14 controls. There was no significant difference bet ween the groups for the postural sway parameters obtained when the eye s were open. Significant differences were found for X(s), Y-s (SDs of the coordinates of the centre of pressure); X(m), Y-m (mean deviation of the coordinates of the centre of pressure); R(m) (average displacem ent of X(i), Y-i, from X(o), Y-o); L (length of sway path); Vel (mean velocity of the centre of pressure along its path); % (area included w ithin the path of the centre of pressure); A(e) (95% confidence ellipt ical area). The Romberg ratios (the relation between eyes closed and o pen) for the Vel, L, A(o) and A(e) of the exposed workers were also si gnificantly different from the controls. Conclusion-The study showed t hat workers exposed to lead had significantly poorer postural stabilit y than the controls. Lead may affect certain parts of the whole sensor y neural axis resulting in postural instability when the visual input is cut off. Based on current blood lead concentrations, we were not ab le to obtain any significant association with the postural sway parame ters.