Vol. 9, No. 4, 2003 Page 7
Two recent studies illustrate the additive effects of biological insults on brain function.
In one study, Maryse Bouchard et al. compared manganese workers who drank heavily with those who drank lightly, and found that workers with the highest alcohol consumption and the highest blood levels of manganese, a toxic metal, displayed the highest scores for mood disorder. In addition, they found that "in the lower [blood] manganese category, those in the higher alcohol consumption group did not have higher scores than the others." The interactive effects of alcohol and high manganese were 'most significant for depression, anger, fatigue, and confusion.
In a separate study, Robert Kahn et al. found that hyperactivity and oppositional behavior were linked to a specific allele of the dopamine transporter (DAT) gene, but only in children whose mothers smoked during pregnancy. Neither the DAT allele nor prenatal smoke exposure alone was significantly associated with elevated behavior problems.
"Blood manganese and alcohol consumption interact on mood states among manganese alloy production workers," M. Bouchard, D. Mergler, M. Baldwin, M. P. Sassine, R. Bowler, and B. MacGibbon, Neurotoxicology, Vol. 24, No. 4-5, August 2003, 641-7. Address: M. Bouchard, CINBIOSE, University of Quebec in Montreal, Montreal, Quebec, Canada.
"Role of dopamine transporter genotype and maternal prenatal smoking in childhood hyperactive-impulsive, inattentive, and oppositional behaviors," R. S. Kahn, J. Khoury, W. C. Nichols, and B. P. Lanphear, Journal of Pediatrics, Vol. 143, No. 1, July 2003, 104-10. Address: R. S. Kahn, Div. General and Community Pediatrics, Cincinnati Children's Hospital Medical Center, Cincinnati, OH 45229.