Cognitive function in a cohort of Danish steel workers.
OBJECTIVE
The aim of this study was to evaluate the level of possible cognitive impairment in a cohort of steel workers occupationally exposed to manganese and lead.


METHODS
Ninety-two employees from an electro-steel works were examined in 1989 and 1995. Fifty-three were re-examined in 2003. Median age of the participants was 53 years, median duration of employment was 24 years, median blood manganese in 1989 and 1995 was 148 and 171 nmol/l, respectively, and median blood lead in 1989 was 0.79 micromol/l. Non-participants were comparable with participants, although they had a higher level of blood manganese in 1989 (186 nmol/l) and 1995 (186 nmol/l). Manganese level in the air was estimated below 1.9 mg/m3 in the 1970s. In the 1990s, manganese level in the air was below 0.28 mg/m3 in the majority of measurements.


METHODS
Cognitive function was examined with the Cognitive Function Scanner, a computer-based neuropsychological test battery. From a published set of norms a subgroup (n=106) matched for gender, age and social status was extracted and used for comparison.


RESULTS
Learning and memory, visuomotor and visuospatial function, concentration, attention, perception and vigilance were examined. Despite many statistically significant differences between the groups, it was not possible to interpret the results for the steel workers as being better or worse. In a visuomotor subtest, the pen-to-point test, the steel workers were much less accurate than the comparison group. This could be the result of an impaired ability to make fast accurate movements. There were no associations between pen-to-point test results and duration of employment or blood levels of manganese and lead.


CONCLUSIONS
Intellectual impairment could not be shown with the Cognitive Function Scanner in this cohort of low to moderate manganese and lead exposed steel workers. A slight subclinical impairment of the visuomotor function was possibly found.
Blond
Morten
M
Clinic of Occupational Medicine, Hilleroed Hospital, Hilleroed, Denmark. mobl@dadlnet.dk
Netterstrom
Bo
B
Laursen
Peter
P
D000328:Adult; D000368:Aged; D000393:Air Pollutants / Q000009:adverse effects* / Q000097:blood; D015415:Biomarkers / Q000097:blood; D016022:Case-Control Studies; D003071:Cognition / Q000187:drug effects*; D015331:Cohort Studies; D003430:Cross-Sectional Studies; D003718:Denmark; D006801:Humans; D007360:Intelligence / Q000187:drug effects; D007854:Lead / Q000009:adverse effects* / Q000097:blood; D008297:Male; D008345:Manganese / Q000097:blood; D017895:Manganese Compounds / Q000009:adverse effects*; D020149:Manganese Poisoning / Q000097:blood / Q000209:etiology* / Q000523:psychology; D008669:Metallurgy; D008875:Middle Aged; D009784:Occupational Diseases / Q000097:blood / Q000139:chemically induced* / Q000523:psychology; D016273:Occupational Exposure; D013232:Steel
D000393:Air Pollutants; D015415:Biomarkers; D017895:Manganese Compounds; D013232:Steel; D007854:Lead; D008345:Manganese