Cognitive performance in elderly women: significance of the 19bp insertion/deletion polymorphism in the 5' flank of the dopamine beta-hydroxylase gene, educational level, body fat measures, serum triglyceride, alcohol consumption and age.
BACKGROUND
Genetic and environmental factors influence cognitive aging. The gene encoding dopamine beta-hydroxylase (DBH) could be one such factor since this hydroxylase converts dopamine to norepinephrine both of which are involved in cognition regulation.


OBJECTIVE
To assess the effect of the 19bp insertion/deletion polymorphism in the 5' flank of the DBH gene on cognitive performance in elderly women relative to other factors of cognitive aging.


METHODS
We examined a cross-sectional sample of 1371 postmenopausal women. Cognitive abilities were assessed by the 6-item orientation-memory-concentration test. The 19bp insertion/deletion polymorphism of the DBH gene was genotyped and apolipoprotein E (APOE) epsilon4 allele status was determined. In addition blood pressure, body fat mass and blood lipids were measured. Information was also obtained by personal interviews. Data were analyzed by regression analysis.


RESULTS
Cognition was univariately associated with DBH genotype (p = 0.04). A univariate association of borderline significance was observed for APOE epsilon4 allele status (p = 0.07). Exclusion of women with severe cognition impairment did not alter the strength of the association with the DBH gene polymorphism markedly (p = 0.06) but obliterated the weak association between APOE epsilon4 allele status and cognition. The association of the DBH gene polymorphism with cognition persisted after adjustment for other variables (p = 0.03).


CONCLUSIONS
The 19bp insertion/deletion polymorphism of the DBH gene influences cognition in elderly women and might have a stronger effect than APOE epsilon4 allele status on mild cognitive impairment. Both genetic polymorphisms had a significantly smaller impact on cognition than age, education, alcohol consumption and body fat measures.
Togsverd
Mads
M
Research Institute of Biological Psychiatry, H:S Sct. Hans Hospital, Roskilde, Copenhagen University, Denmark.
Werge
Thomas M
TM
Tankó
Laszlo B
LB
Bagger
Yu Z
YZ
Qin
George G
GG
Hansen
Thomas
T
Christiansen
Claus
C
Rasmussen
Henrik B
HB
D020121:5' Untranslated Regions; D000367:Age Factors; D000368:Aged; D000369:Aged, 80 and over; D000428:Alcohol Drinking; D001823:Body Composition; D003071:Cognition / Q000502:physiology*; D003430:Cross-Sectional Studies; D004299:Dopamine beta-Hydroxylase / Q000235:genetics*; D004522:Educational Status; D005260:Female; D020022:Genetic Predisposition to Disease; D005838:Genotype; D006801:Humans; D008055:Lipids / Q000097:blood; D008609:Mental Status Schedule; D008875:Middle Aged; D015999:Multivariate Analysis; D011110:Polymorphism, Genetic; D011581:Psychological Tests; D012044:Regression Analysis; D012307:Risk Factors; D014280:Triglycerides / Q000097:blood
D020121:5' Untranslated Regions; D008055:Lipids; D014280:Triglycerides; D004299:Dopamine beta-Hydroxylase