Chia S E, Chia H P, Ong C N, Jeyaratnam J
Department of Community Occupational and Family Medicine, National University of Singapore.
Occup Environ Med. 1996 Apr;53(4):264-8. doi: 10.1136/oem.53.4.264.
To study the association in a group of battery manufacturing workers between computerised postural sway parameters and present concentrations of blood lead (PPb), index of cumulative blood lead years (CBI), and cumulative blood lead at different years of exposure (CPbYs).
Postural stability was investigated with a computerised postural sway measurement system in 60 workers exposed to lead with exposure duration of 84 (range 3-366) months and in 60 control subjects. An index of CBIs in 55 workers (previous blood lead results of five workers were not available) and CPbYs were computed for each worker by calculating the area under the curve of concentrations of blood lead against time.
The mean (SD) PPb was 36.0 (11.7) (range 6.4 to 64.5) micrograms/dl for the exposed workers and 6.3 (2.4) (range 3.1-10.9) micrograms/dl for the 14 randomly selected control subjects. Significant differences between groups for the postural sway parameters obtained when the eyes were closed were found for length of sway path (L); mean velocity of the centre of pressure along its path (Vel); area included within the path of the centre of pressure (Ao); 95% confidence elliptical area (Ae). The Romberg ratio (the relation between eyes closed and open) for the Vel, L, Ao, and Ae of the exposed group were also significantly different from those of the controls. The postural sway parameters (eyes closed) were not significantly correlated with PPb or CBI. However, the cumulative blood lead for the past two years before the postural sway assessment, CPbY2, was significantly correlated with all the postural sway parameters.
The study showed that workers exposed to lead had significantly poorer postural stability than a control group. Lead may affect certain parts of the somatosensory system resulting in postural instability when the visual input is cut off. The CPbY2 was significantly positively correlated with most of the postural sway parameters. Effects of lead on postural stability may be related to recent increases in blood lead concentration among the exposed workers rather than to cumulative body burden.
研究一组电池制造工人的计算机化姿势摆动参数与当前血铅浓度（PPb）、血铅累积年限指数（CBI）以及不同暴露年限的血铅累积量（CPbYs）之间的关联。
采用计算机化姿势摆动测量系统对60名铅暴露工人（暴露时长为84个月，范围3 - 366个月）和60名对照者的姿势稳定性进行研究。通过计算血铅浓度随时间变化曲线下的面积，为55名工人（5名工人之前的血铅结果不可用）计算CBI指数和CPbYs。
暴露工人的平均（标准差）PPb为36.0（11.7）（范围6.4至64.5）微克/分升，14名随机选择的对照者为6.3（2.4）（范围3.1 - 10.9）微克/分升。闭眼时获得的姿势摆动参数在两组之间存在显著差异，包括摆动路径长度（L）；压力中心沿其路径的平均速度（Vel）；压力中心路径内包含的面积（Ao）；95%置信椭圆面积（Ae）。暴露组的Vel、L、Ao和Ae的罗姆伯格比率（闭眼与睁眼之间的关系）也与对照组显著不同。姿势摆动参数（闭眼）与PPb或CBI无显著相关性。然而，姿势摆动评估前两年的血铅累积量CPbY2与所有姿势摆动参数显著相关。
研究表明，铅暴露工人的姿势稳定性明显低于对照组。铅可能会影响体感系统的某些部分，导致视觉输入切断时出现姿势不稳定。CPbY2与大多数姿势摆动参数显著正相关。铅对姿势稳定性的影响可能与暴露工人近期血铅浓度升高有关，而非与体内累积负担有关。
