Trace element levels and cognitive function in rural elderly Chinese.
BACKGROUND
Trace elements are involved in metabolic processes and oxidation-reduction reactions in the central nervous system and could have a possible effect on cognitive function. The relationship between trace elements measured in individual biological samples and cognitive function in an elderly population had not been investigated extensively.


METHODS
The participant population is part of a large cohort study of 2000 rural elderly Chinese persons. Six cognitive assessment tests were used to evaluate cognitive function in this population, and a composite score was created to represent global cognitive function. Trace element levels of aluminum, calcium, cadmium, copper, iron, lead, and zinc were analyzed in plasma samples of 188 individuals who were randomly selected and consented to donating fasting blood. Analysis of covariance models were used to assess the association between each trace element and the composite cognitive score adjusting for demographics, medical history of chronic diseases, and the apolipoprotein E (APOE) genotype.


RESULTS
Three trace elements-calcium, cadmium, and copper-were found to be significantly related to the composite cognitive score. Increasing plasma calcium level was associated with higher cognitive score (p <.0001). Increasing cadmium and copper, in contrast, were significantly associated with lower composite score (p =.0044 and p =.0121, respectively). Other trace elements did not show significant association with the composite cognitive score.


CONCLUSIONS
Our results suggest that calcium, cadmium, and copper may be associated with cognitive function in the elderly population.
Gao
Sujuan
S
Department of Medicine, Indiana University School of Medicine, 410 West 10th Street, Suite 3000, Indianapolis, IN 46202, USA. sgao@iupui.edu
Jin
Yinlong
Y
Unverzagt
Frederick W
FW
Ma
Feng
F
Hall
Kathleen S
KS
Murrell
Jill R
JR
Cheng
Yibin
Y
Shen
Jianzhao
J
Ying
Bo
B
Ji
Rongdi
R
Matesan
Janetta
J
Liang
Chaoke
C
Hendrie
Hugh C
HC
D000368:Aged; D000535:Aluminum / Q000097:blood; D002104:Cadmium / Q000097:blood*; D002118:Calcium / Q000097:blood*; D002681:China; D003071:Cognition / Q000502:physiology*; D015331:Cohort Studies; D003300:Copper / Q000097:blood*; D005260:Female; D006801:Humans; D007501:Iron / Q000097:blood; D007854:Lead / Q000097:blood; D008297:Male; D011897:Random Allocation; D012424:Rural Population; D015032:Zinc / Q000097:blood
D002104:Cadmium; D007854:Lead; D003300:Copper; D000535:Aluminum; D007501:Iron; D015032:Zinc; D002118:Calcium