Neurobehavioural evaluation of Venezuelan workers exposed to inorganic lead.

Abstract

Objectives-To assess neurobehavioural effects of low exposure to lead, 43 workers from a lead smelter and 45 workers from a glass factory were evaluated with the World Health Organisation neurobehavioural core test battery (NCTB) in a cross sectional study. Methods-The NCTB comprises a questionnaire and seven tests that measure simple reaction time, short term memory (digit span, Benton), mood (profile of mood states), eye-hand coordination (Santa Ana pegboard, pursuit aiming II), and perceptual speed (digit-symbol). Results-Smelter workers were employed on average for four years, and had a mean blood lead concentration of 2'0 cumolll (42 ug/dl). Glass factory workers had a mean of 0*72 umoill (15 ugldl). Historical blood lead concentrations were used to classify exposure based on current, peak, and time weighted average. Although the exposed workers performed less well than the non-exposed in 10 of 14 response variables, only profile of mood states tension-anxiety, hostility, and depression mood scales showed a significantly poorer dose-response relation with blood lead concentration in multiple linear regression models that included age, education, and alcohol intake as covariates. The frequency of symptoms of anger, depression, fatigue, and joint pain were also significantly increased in the exposed group. Conclusion-This study is consistent with the larger body of neurobehavioural research of low occupational exposure to lead. The small effects found in this study occurred at blood lead concentrations slightly lower than those reported in several previous studies.

Reduced cognitive abilities in lead-exposed men

“…However, this inconsistency disappears in a meta-analysis by Meyer-Baron and Seeber [18], which is based on the studies mentioned. The finding of unaffected reaction time by lead is in accordance with the findings of Haenninen et al [12], Maizlish et al [16] Campara et al [5] and Repko et al [22]. They are in conflict with Williamson and Teo [29].…”

Characterizing Golden Eagle Risk to Lead and Anticoagulant Rodenticide Exposure: A Review

“…Baker et al (1983) reported impaired verbal concept formation, memory, and visual/motor performance among workers with PbB >40 μg/dL. Similar findings were reported in a cohort of 43 Venezuelan workers from a lead smelter who had a mean-employment duration of 4 years and a mean PbB of 42 μg/dL (Maizlish et al 1995). The authors observed a significant association between altered mood states and current, peak, and timeweighted average (TWA) blood lead levels.…”

No cognitive deficits in men formerly exposed to lead

“…Many human and experimental studies during past decades have demonstrated adverse effects on the central nervous system (CNS) after chronic exposure to inorganic lead [3][4][5]. Neuropsychological symptoms and cognitive deficits have been the main manifestations of milder adverse effects, and although several studies have demonstrated the neuropsychological effects of current lead exposure [6][7][8][9][10][11] only a few studies have examined cognitive abilities after long-term exposure has ceased [12,13]. Results from the two latter studies are controversial, and it remains unclear whether reduced cognitive abilities from chronic low-level lead exposure are reversible or not [11].…”