Blood mercury levels and neurobehavioral function.
BACKGROUND
Due to its cardiovascular benefits, fish consumption is widely encouraged among older Americans. However, this fast-growing population is at increased risk of cognitive impairment and may be particularly sensitive to methylmercury, a neurotoxicant found in fish.


OBJECTIVE
To describe associations of blood mercury levels with neurobehavioral test scores in an urban adult population.


METHODS
Cross-sectional analysis to determine the effect of mercury levels on neurobehavior in 474 randomly selected participants in the Baltimore Memory Study, a longitudinal study of cognitive decline involving 1140 Baltimore residents aged 50 to 70 years. We measured total mercury in whole blood samples and used multiple linear regression to examine its associations with neurobehavioral test scores. First-visit data were obtained in 2001-2002.


METHODS
Twenty scores from 12 neurobehavioral tests.


RESULTS
The median blood mercury level was 2.1 microg/L (range, 0-16 microg/L). After adjustment for covariates, increasing blood mercury was associated with worse performance on Rey complex figure delayed recall, a test of visual memory (beta, -0.224; 95% confidence interval, -0.402 to -0.047). However, increasing blood mercury levels were associated with better performance on finger tapping, a test of manual dexterity (beta for dominant hand, 0.351; 95% confidence interval, 0.017-0.686).


CONCLUSIONS
Overall, the data do not provide strong evidence that blood mercury levels are associated with worse neurobehavioral performance in this population of older urban adults.
Weil
Megan
M
Department of Environmental Health Sciences, Johns Hopkins Bloomberg School of Public Health, Baltimore, Md, USA. mweil@jhsph.edu
Bressler
Joseph
J
Parsons
Patrick
P
Bolla
Karen
K
Glass
Thomas
T
Schwartz
Brian
B
D000328:Adult; D000368:Aged; D000818:Animals; D015142:Baltimore / Q000453:epidemiology; D003071:Cognition; D003430:Cross-Sectional Studies; D004034:Diet Surveys; D005260:Female; D005399:Fishes; D006801:Humans; D016014:Linear Models; D008297:Male; D008568:Memory; D008628:Mercury / Q000097:blood*; D020262:Mercury Poisoning, Nervous System / Q000453:epidemiology; D008767:Methylmercury Compounds / Q000633:toxicity; D008875:Middle Aged; D009483:Neuropsychological Tests; D011597:Psychomotor Performance; D012306:Risk; D017747:Seafood / Q000633:toxicity
D008767:Methylmercury Compounds; D008628:Mercury