Plasma trace elements and cognitive function in older men and women: the Rancho Bernardo study.
OBJECTIVE
This study examines the sex-specific associations of plasma concentrations of iron, copper, and zinc with cognitive function in older community-dwelling adults.


METHODS
Cross-sectional study.


METHODS
1988-92 follow-up clinic visit.


METHODS
602 men and 849 women (average age=75 +/- 8 years) who were community-dwelling and not clinically demented.


METHODS
Blood samples were assayed for trace elements and 12 cognitive function tests were administered. Sex-specific analyses were adjusted for age, education, alcohol consumption, smoking, exercise, and estrogen use in women.


RESULTS
Men and women differed significantly in education and alcohol intake (p's < 0.001), concentrations of plasma iron, copper and zinc (p's < 0.001) and scores on 11 of 12 cognitive function tests (p=0.04 to < 0.001). Regression analyses showed significant inverted U-shaped associations in men; both low and high iron levels were associated with poor performance on total and long-term recall and Serial 7's (p's=0.018, 0.042 and 0.004, respectively) compared to intermediate concentrations. In women, iron and copper concentrations had inverse linear associations with Buschke total, long and short-term recall and Blessed scores (p's < 0.05). Zinc was positively associated with performance on Blessed Items (p=0.008). Analyses comparing cognitive function using categorically defined mineral concentrations yielded similar sex specific results.


CONCLUSIONS
Optimal trace element concentrations may exist for optimal cognitive function in older adults, and these levels may differ by sex and cognitive function domain.
Lam
P K
PK
Department of Family and Preventive Medicine, University of California San Diego, 9500 Gilman Drive, 0607, La Jolla, CA 92093-0607, USA.
Kritz-Silverstein
D
D
Barrett Connor
E
E
Milne
D
D
Nielsen
F
F
Gamst
A
A
Morton
D
D
Wingard
D
D
D000367:Age Factors; D000368:Aged; D000375:Aging / Q000097:blood* / Q000523:psychology*; D000428:Alcohol Drinking; D003071:Cognition / Q000502:physiology*; D003072:Cognition Disorders / Q000097:blood*; D003300:Copper / Q000097:blood; D003430:Cross-Sectional Studies; D004522:Educational Status; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D007501:Iron / Q000097:blood; D008297:Male; D008568:Memory; D011939:Mental Recall; D008609:Mental Status Schedule; D009483:Neuropsychological Tests; D011159:Population Surveillance; D012737:Sex Factors; D011795:Surveys and Questionnaires; D014131:Trace Elements / Q000097:blood*; D015032:Zinc / Q000097:blood
D014131:Trace Elements; D003300:Copper; D007501:Iron; D015032:Zinc