Neurocognitive impact of metal exposure and social stressors among schoolchildren in Taranto, Italy.

BACKGROUND: Metal exposure is a public health hazard due to neurocognitive effects starting in early life. Poor socio-economic status, adverse home and family environment can enhance the neurodevelopmental toxicity due to chemical exposure. Disadvantaged socio-economic conditions are generally higher in environmentally impacted areas although the combined effect of these two factors has not been sufficiently studied. METHODS: The effect of co-exposure to neurotoxic metals including arsenic, cadmium, manganese, mercury, lead, selenium, and to socio-economic stressors was assessed in a group of 299 children aged 6-12 years, residing at incremental distance from industrial emissions in Taranto, Italy. Exposure was assessed with biological monitoring and the distance between the home address and the exposure point source. Children's cognitive functions were examined using the Wechsler Intelligence Scale for Children (WISC) and the Cambridge Neuropsychological Test Automated Battery (CANTAB). Linear mixed models were chosen to assess the association between metal exposure, socio-economic status and neurocognitive outcomes. RESULTS: Urinary arsenic, cadmium and hair manganese resulted inversely related to the distance from the industrial emission source (ß - 0.04; 95% CI -0.06, - 0.01; ß - 0.02; 95% CI -0.05, - 0.001; ß - 0.02 95% CI -0.05, - 0.003) while the WISC intellectual quotient and its sub-scores (except processing speed index) showed a positive association with distance. Blood lead and urinary cadmium were negatively associated with the IQ total score and all sub-scores, although not reaching the significance level. Hair manganese and blood lead was positively associated with the CANTAB between errors of spatial working memory (ß 2.2; 95% CI 0.3, 3.9) and the reaction time of stop signal task (ß 0.05; 95% CI 0.02, 0.1) respectively. All the other CANTAB neurocognitive tests did not show to be significantly influenced by metal exposure. The highest socio-economic status showed about five points intellectual quotient more than the lowest level on average (ß 4.8; 95% CI 0.3, 9.6); the interaction term between blood lead and the socio-economic status showed a significant negative impact of lead on working memory at the lowest socio-economic status level (ß - 4.0; 95% CI -6.9, - 1.1). CONCLUSIONS: Metal exposure and the distance from industrial emission was associated with negative cognitive impacts in these children. Lead exposure had neurocognitive effect even at very low levels of blood lead concentration when socio-economic status is low, and this should further address the importance and prioritize preventive and regulatory interventions.

An integrated model for the assessment of stress-related risk factors in health care professionals.

To assess the risk from exposure to occupational stress and burnout in health care workers (HCW), a cross-sectional study was planned to compare objective data that can represent potential job stressors in hospital wards and subjective symptoms reported by the workers. Medical doctors, nurses and ancillary workers of the Internal Medicine Wards of a large public hospital in Northern Italy participated in the study. Three subjective questionnaires were administered: the Job Content Questionnaire (JCQ), the State-Trait Anxiety Inventory (STAI), the Maslach Burnout Inventory (MBI). In addition, seven objective parameters were collected as average during the 3 months period prior to the study: a) working understaffed; b) ratio number of patients/HCW on service; c) ratio number of HCW on sick leave/ HCW on service; d) number of skipped days off after night shifts; e) days of sick leave; f) number of deceased patients; g) number of accidents at work. A total group of 230 HCW were examined, employed in six different sub-units of the Medical wards. The female workers were 67.8% and the male workers 32.2%, the mean age was 37.4 yr (SD 9.3) in the total group of HCW, 35.1 yr (SD 7.9) in females and 42.3 yr (SD 10.3) in males. The average scores of subjective and objective parameters resulted significantly higher in the same sub-units. The correlation analysis showed that the subjective questionnaires were highly inter-related. The multivariate analysis showed that the days of sick leave were significantly related to the subjective questionnaires, and the subjective subscales of emotional exhaustion (from MBI), job demand and decision latitude (from JCQ) and STAIt were significantly related to some of the objective parameters. These results support the integrated use of multiple subjective and objective assessment as the most appropriate approach for the evaluation of occupational stress.

Neuropsychological testing for the assessment of manganese neurotoxicity: a review and a proposal.

BACKGROUND: Manganese exposure can cause neurobehavioral and neurological signs and symptoms. A review of the literature was carried out in order to identify the most sensitive and effective methods to assess these outcomes. METHODS: Studies on manganese exposure performed with neuropsychological tests were reviewed using Medline. Test methods, obtained outcomes, and dose-response relationships were considered. Based on the review and additional considerations, a testing battery for adult and children was identified. RESULTS: A total number of 31 studies were reviewed and divided in 18 occupational, 7 environmental, and 6 on children. A large variety of tests exploring motor and cognitive functions and mood were applied. Neurobehavioral effects were dose-dependent in several studies and determined by much lower exposure levels compared to 1 mg Mn/m(3) in total dust which is considered to be the minimum concentration able to induce the classical clinical features of "manganism." Although through a wide variety of tests, the observed outcomes support the knowledge that manganese exposure can cause neurobehavioral effects. Motor functions are mainly affected in adults, and cognitive functions and behavior are more affected in children. CONCLUSIONS: Literature on manganese neurobehavioral effect is quite consistent, however, further improvement may be achieved by using better structured and more comparable evaluation methods. Based on the analysis of the existing experiences a test battery including tests of motor functions, response speed, cognitive functions, intellectual abilities, mood, and symptom questionnaires is suggested. We recommend that the tests indicated should always be included in future studies as a core battery.