A follow-up study of nerve conduction velocities in lead exposed workers

A group of 23 storage battery workers exposed to lead was studied when entering for the first time lead exposed work. Follow-up examinations were performed after one and two years of work and the same measurements were similarly performed to matched controls. The motor distal latency of the median nerve became significantly longer and the distal sensory conduction velocity of the median nerve slower among the lead workers already during the first year of lead work. At the 2-yr examination also the mean hemoglobin level was slightly lower for the lead workers. The impairment in the nerve conduction velocities was mainly due to those workers whose blood lead level had quickly risen to above 30 micrograms/100 ml, the maximal blood lead within the group being 48 micrograms/100 ml, while those workers whose blood lead remained below 30 micrograms/100 ml had similar conduction velocities as the controls.