Bouchard M, Mergler D, Baldwin ME, Panisset M
Centre de recherche interdisciplinaire sur la biologie, la sant? la soci??et l'environnement, Universit?du Qu?ec ?Montr?l, Montr?l, Canada. bouchard.maryse@uqam.ca

Long-term exposure to manganese (Mn) particulates through inhalation can be neurotoxic, with deficits in neuromotor and cognitive domains. Mn-exposed individuals also report symptoms, including fatigue, mood changes, irritability, concentration difficulties, and sweating in the absence of physical effort. The long-term course of Mn-related symptoms after cessation of exposure has never been examined. Male workers from a Mn-alloy production plant participated in a study on nervous system functions (initial examination), and were followed-up 14 years after plant closure. The relation between self-reported symptoms and Mn cumulative exposure index (CEI) was examined among 71 Mn-alloy workers and 71 referents. Symptoms from the questionnaire were grouped into categories, and the reported frequency was compared between referents and Mn-alloy workers in each Mn CEI tertile using General Linear Models, controlling for age, education, and alcohol consumption. A gradual increase in symptoms frequency was observed for complaints related to hearing and movement control both at initial and follow-up examination, and fatigue and autonomic nervous system only at initial examination. In addition, an exposure-effect relation was apparent for symptoms related to memory, concentration and balance reported at both examinations, with Mn-workers in the highest CEI tertile reporting the highest level of symptomatology. Sleeping complaints were not associated with exposure to Mn, while musculoskeletal pain and muscular weakness were reported more often by Mn-workers than referents but were not clearly related to CEI. The findings suggest that former Mn-alloy workers continue to perceive symptoms many years after cessation of exposure. Despite the limitations of self-reported symptoms, subjective complaints are an important part of a health assessment since they relate directly to perceived health status and day-to-day functioning.

Related citations

- Neurobehavioral functioning after cessation of manganese exposure: a follow-up after 14 years.
Neurobehavioral functioning after cessation of manganese exposure: a follow-up after 14 years.
Bouchard M, Mergler D, Baldwin M, Panisset M, Bowler R, Roels HA. Am J Ind Med. 2007 Nov; 50(11):831-40.

- Self-reported symptoms and their effects on cognitive functioning in workers with past exposure to solvent-based glues: an 18-year follow-up.
[Int Arch Occup Environ Health. 2007]
Self-reported symptoms and their effects on cognitive functioning in workers with past exposure to solvent-based glues: an 18-year follow-up.
Nordling Nilson L, Barreg?d L, S?lsten G, Hagberg S. Int Arch Occup Environ Health. 2007 Oct; 81(1):69-79. Epub 2007 Apr 5.

- Neuropsychiatric symptoms and past manganese exposure in a ferro-alloy plant.
[Neurotoxicology. 2007] Neuropsychiatric symptoms and past manganese exposure in a ferro-alloy plant.
Bouchard M, Mergler D, Baldwin M, Panisset M, Roels HA. Neurotoxicology. 2007 Mar; 28(2):290-7. Epub 2006 Aug 12.

- Review Manganese exposure and the neuropsychological effect on children and adolescents: a review.
[Rev Panam Salud Publica. 2009] Review Manganese exposure and the neuropsychological effect on children and adolescents: a review.
Menezes-Filho JA, Bouchard M, Sarcinelli Pde N, Moreira JC. Rev Panam Salud Publica. 2009 Dec; 26(6):541-8.

- Review Neurologic effects of manganese in humans: a review.
[Int J Occup Environ Health. 2003] Review Neurologic effects of manganese in humans: a review.
Levy BS, Nassetta WJ. Int J Occup Environ Health. 2003 Apr-Jun; 9(2):153-63.

Cited by 1 PubMed Central article:

- Identifying natural and anthropogenic sources of metals in urban and rural soils using GIS-based data, PCA, and spatial interpolation. [Environ Pollut. 2009]
Identifying natural and anthropogenic sources of metals in urban and rural soils using GIS-based data, PCA, and spatial interpolation.
Davis HT, Aelion CM, McDermott S, Lawson AB.
Environ Pollut. 2009 Aug-Sep; 157(8-9):2378-85. Epub 2009 Apr 10.

Source:  http://www.ncbi.nlm.nih.gov/pubmed/18562007