Autonomic and central nervous system effects of lead in female glass workers in China

To clarify the effects of lead on autonomic and central nervous system functions, electrocardiographic R-R interval variability (CVRR) as well as visual and brainstem auditory evoked potentials (VEP and BAEP) were measured in 36 female workers exposed to lead (exposed group) and in 15 female textile workers (unexposed group). The C-CVLF, C-CVHF (two component CVs of the CVRR reflecting sympathetic and parasympathetic activities, respectively), and LF/HF ratio (indicator of sympatho-vagal balance) were also computed from component spectral powers by means of autoregressive spectral and component analyses. The exposed group had engaged in glass work for 2-17 (mean 7.8) years. Blood lead (BPb) concentrations were 25.8-79.3 (mean 55.6) micrograms/dl in the exposed group and 4.7-8.6 (mean 6.3) micrograms/dl in the unexposed group. The CVRR, C-CVLF, C-CVHF, and LF/HF ratio in the exposed group were significantly lower than those in the unexposed group. Also, the exposed group had more complaints of subjective symptoms and signs than did the unexposed group. On the other hand, no significant differences in either VEP or BAEP latencies were found between the two groups. It is suggested that autonomic nervous function is more susceptible to lead than visual and auditory nervous functions; lead affects sympathetic activity more strongly than parasympathetic activity.