Occupational lead neurotoxicity: A behavioural and electrophysiological evaluation. study design and year one results.

To evaluate the effects of chronic lead exposure on the nervous system in adults, a set of neurobehavioural and electrophysiological tests was administered to 99 lead exposed foundry employees and 61 unexposed workers. Current and past blood lead concentrations were used to estimate the degree of lead absorption; all previous blood lead concentrations had been less than or equal to 90 micrograms/100 ml. Characteristic signs (such as wrist extensor weakness) or symptoms (such as colic) of lead poisoning were not seen. Sensory conduction in the sural nerve was not affected. By contrast, various neurobehavioural functions deteriorated with increasing lead burden. Workers with blood lead concentrations between 40 and 60 micrograms/100 ml showed impaired performance on tests of verbal concept formation, visual/motor performance, memory, and mood. Thus impairment in central nervous system function in lead exposed adults occurred in the absence of peripheral nervous system derangement and increased in severity with increasing lead dose.

Occupational lead neurotoxicity: Improvement in behavioural effects after reduction of exposure.

To evaluate critical exposure levels and the reversibility of lead neurotoxicity a group of lead exposed foundry workers and an unexposed reference population were followed up for three years. During this period, tests designed to monitor neurobehavioural function and lead dose were administered. Evaluations of 160 workers during the first year showed dose dependent decrements in mood, visual/motor performance, memory, and verbal concept formation. Subsequently, an improvement in the hygienic conditions at the plant resulted in striking reductions in blood lead concentrations over the following two years. Attendant improvement in indices of tension (20% reduction), anger (18%), depression (26%), fatigue (27%), and confusion (13%) was observed. Performance on neurobehavioural testing generally correlated best with integrated dose estimates derived from blood lead concentrations measured periodically over the study period; zinc protoporphyrin levels were less well correlated with function. This investigation confirms the importance of compliance with workplace standards designed to lower exposures to ensure that individual blood lead concentrations remain below 50 micrograms/dl.

Why do Nigerian manufacturing firms take action on AIDS?

Objective: To identify differences between manufacturing firms in Nigeria that have undertaken HIV/AIDS prevention activities and those that have not as a step toward improving the targeting of HIV policies and interventions. Methods: A survey of a representative sample of registered manufacturing firms in Nigeria, stratified by location, workforce size, and industrial sector. The survey was administered to managers of 232 firms representing most major industrial areas and sectors in March-April 2001. Results: 45.3 percent of the firms’ managers received information about HIV/AIDS from a source outside the firm in 2000; 7.7 percent knew of an employee who was HIV-positive at the time of the survey; and 13.6 percent knew of an employee who had left the firm and/or died in service due to AIDS. Only 31.7 percent of firms took any action to prevent HIV among employees in 2000, and 23.9 percent had discussed the epidemic as a potential business concern. The best correlates of having taken action on HIV were knowledge of an HIV-positive employee or having lost an employee to AIDS (odds ratio [OR] 6.36, 95% confidence interval [CI]: 2.30, 17.57) and receiving information about the disease from an outside source (OR 7.83, 95% CI: 3.46, 17.69). Conclusions: Despite a nationwide HIV seroprevalence of 5.8 percent, as of 2001 most Nigerian manufacturing firm managers did not regard HIV/AIDS as a serious problem and had neither taken any action on it nor discussed it as a business issue. Providing managers with accurate, relevant information about the epidemic and practical prevention interventions might strengthen the business response to AIDS in countries like Nigeria.