Neuropsychiatric symptoms and past manganese exposure in a ferro-alloy plant.
BACKGROUND
Psychiatric manifestations have been reported in cases of manganism, and mood disorders are often observed in manganese (Mn) exposed workers. We examined neuropsychiatric symptoms among formerly Mn-exposed workers 14 years after cessation of exposure.


METHODS
A study was conducted in 1990 among workers from a ferro- and silico-Mn plant and unexposed working men referents from the same region in South-West Quebec. At follow-up in 2004, 77 former Mn-workers and 81 referents agreed to participate and responded to a neuropsychiatric symptom checklist, the Brief Symptom Inventory (BSI); scores were transformed into T-scores based on a normative population. Cumulated exposure indices (CEI) were computed for each former Mn-worker. Linear and logistic regression analyses were used.


RESULTS
Mean T-scores were significantly higher among former Mn-workers than referents on scales of Depression and Anxiety. Mean T-scores of psychological distress increased with the CEI tertiles, with significant associations for the scales Somatization, Depression, Anxiety and Hostility. Former Mn-workers in the two highest tertiles of CEI showed a higher risk for T-scores >or=63 for Hostility (OR, 7.5; 95% CI, 1.5-38.9), Depression (OR, 2.6; 95% CI, 1.1-8.4) and Anxiety (OR, 3.0; 95% CI, 1.1-8.4).


CONCLUSIONS
These results suggest that past exposure to Mn may have lasting consequences on neuropsychiatric symptoms.
Bouchard
Maryse
M
CINBIOSE, Université du Québec à Montréal, Institut des Sciences de l'environnement, CINBIOSE (SB-1983), C.P. 8888, Succ. Centre-Ville, Montréal, Québec H3C 3P8, Canada.
Mergler
Donna
D
Baldwin
Mary
M
Panisset
Michel
M
Roels
Harry A
HA
D000328:Adult; D000339:Affect / Q000187:drug effects; D000368:Aged; D001007:Anxiety / Q000139:chemically induced; D010054:Brief Psychiatric Rating Scale; D016022:Case-Control Studies; D003863:Depression / Q000139:chemically induced; D004644:Emotions / Q000187:drug effects*; D004785:Environmental Pollutants / Q000009:adverse effects*; D006791:Hostility; D006801:Humans; D007501:Iron / Q000009:adverse effects*; D016014:Linear Models; D016015:Logistic Models; D008297:Male; D008345:Manganese / Q000009:adverse effects*; D001523:Mental Disorders / Q000139:chemically induced*; D008669:Metallurgy; D008875:Middle Aged; D009784:Occupational Diseases / Q000139:chemically induced* / Q000523:psychology; D016273:Occupational Exposure; D011792:Quebec; D012828:Silicones / Q000009:adverse effects*; D013315:Stress, Psychological / Q000139:chemically induced
D004785:Environmental Pollutants; D012828:Silicones; C083456:ferro-manganese alloy; D008345:Manganese; D007501:Iron