Neuropsychological test results and symptoms among workers with well-defined long-term exposure to lead.

Abstract

Lead intoxication is a classical environmental hazard that can cause encephalopathy. During recent years several studies have suggested poor performances in psychological tests and increased numbers of subjective symptoms among workers with comparatively low blood lead concentrations. Forty-nine long-term lead-exposed male workers with time-weighted average blood lead concentrations between 1*3 and 3-3 umoUl calculated from at least seven years' results have been compared with a referent group of 27 male industrial workers with normal blood lead concentrations and comparable intellectual backgrounds. Several indices of exposure were used. Both groups were examined with neuropsychological tests and a questionnaire covering neuropsychiatric symptoms. The exposed group performed less well in 11 of 14 non-verbal tests, and there were significant differences in tests of memory and reaction time. A non-linear doseeffect trend was indicated. The results are in accordance with those found in similar studies, and it is concluded that the blood lead concentration should be below 2-5 ,umol/l to avoid the effects shown in this study.Lead intoxication is a classic environmental and occupational hazard that in high doses causes encephalopathy with symptoms such as irritability, depressiveness, and concentration and memory disturbances. During recent years, several studies have suggested poor performance in psychological tests of intellectual functions'`7 and an increased number of subjective symptoms89 among workers with comparatively low blood lead concentrations. The exposure, however, has been either short or not registered regularly. Therefore, it seemed important to study workers exposed for many years with blood lead analyses performed regularly during the time of their exposure. Methods and material LEAD EXPOSUREThe register of workers who had had their blood lead concentrations analysed at the laboratory of the department of occupational medicine in Orebro during 1967-79 was chosen as the source of subjects. The register contained information about the date At the time of the present investigation haemoglobin concentration, the present state of blood lead (B-Pb), and zinc protoporphyrin (B-ZPP) were examined. All blood lead measurements were conducted by the same laboratory during the whole period of measurements and by the same atomic absorption spectrophotometer (Perkin Elmer 403). Blood lead concentration has been recorded two to four times a year in the exposed group. The laboratory had participated regularly in interlaboratory comparisons with approved results. B-ZPP was measured from duplicate samples by the laboratory at the department of occupational medicine in Lund. 10

Cognitive deficits and magnetic resonance spectroscopy in adult monozygotic twins with lead poisoning.

“…Less severe neurologic and behavioral effects have been documented in lead-exposed workers with BPb levels between 40 and 120 µg/dL. Evidence consistently indicates that lead-exposed workers perform worse on tests of visual motor functioning, reaction time, memory, attention, and concentration, with effects on mood also often being noted (Arnvig et al 1980;Baker et al 1984;Campara et al 1984;Grandjean et al 1978;Haenninen et al 1978;Hogstedt et al 1983;Schwartz et al 2001;Stollery 1996;Stollery et al 1991;Valciukas et al 1978).…”

Metabolismo e toxicidade do chumbo na criança e no adulto

“…Em níveis de plumbemia considerados seguros para trabalhadores expostos (entre 40 e 60 µg/dl) tem se observado alterações neurocomportamentais e de sistema nervoso periférico, como redução na velocidade de condução nervosa, em diversos estudos. 39,40 A neuropatia periférica com características clínicas de fraqueza na musculatura extensora, principalmente de membros superiores, com o sinal da mão caída, não é mais diagnosticada atualmente, sendo quadro clínico descrito em relatos históricos em trabalhadores cronicamente expostos a níveis extremamente elevados, típi-cos do final do século XIX e início do século XX.…”

Neuropsychiatric Effects in Workers with Occupational Exposure to Carbon Disulfide

“…Exposure to CS 2 ranging from 3 mg/m 3 to 147 mg/m 3 in a viscose rayon factory in Belgium, had no significant effect on memory or attention 7) . The Swedish questionnaire for neuropsychiatric symptoms Q16 has been used in many occupational groups in different countries exposed to various hazards, mostly to organic solvents 14,[24][25][26][27][28][29][30][31][32][33] , but also to lead 31,34) , welder's metals 35) , styrene [36][37][38] , pesticides 39) and manganese 40) , etc. But in the literature we did not find any implementation of the questionnaire in workers exposed to CS 2 , a well known neurotoxic agent.…”