PPAR-gamma Pro12Ala genotype and risk of cognitive decline in elders.
BACKGROUND
The Pro12Ala polymorphism of peroxisome proliferator-activated receptor-gamma (PPAR-gamma) has been associated with decreased risk of diabetes and obesity, both disorders linked to cognitive impairment. We tested whether this polymorphism is associated with cognition.


METHODS
Two thousand nine hundred sixty-one participants (mean age, 74.1; 41% Black; 52% women) were administered the Modified Mini-Mental State Examination (3MS) and Digit Symbol Substitution Test (DSST) at baseline and 4 year follow-up. Test scores were adjusted for age, sex, education, cerebrovascular disease, depression and APOE genotype and additionally for race. We determined the association between Ala allele and development of cognitive decline (3MS decline of > or = 5 points).


RESULTS
At baseline, unadjusted scores on both cognitive tests were higher for Ala carriers compared to non-carriers (3MS, 94.2 versus 92.5, p<0.001; DSST, 40.2 versus 34.5, p<0.001). Similarly, follow-up scores were higher for Ala carriers. Multivariable adjustment led to similar results; additional adjustment for race attenuated the baseline 3MS results. After 4 years, 17.5% of Ala carriers developed cognitive decline compared to 25% among non-carriers (unadjusted OR=0.61; 95%CI, 0.46-0.82; adjusted OR=0.75; 95%CI, 0.55-1.02). Further adjustment for metabolic variables including fasting blood glucose and lipid level did not change the results.


CONCLUSIONS
The PPAR-gamma Ala12 allele carriers may have less risk of developing cognitive decline.
Yaffe
K
K
Department of Psychiatry and Neurology, University of California, San Francisco, CA 94121, United States. Kristine.yaffe@ucsf.edu
Kanaya
A M
AM
Lindquist
K
K
Hsueh
W C
WC
Cummings
S R
SR
Beamer
B
B
Newman
A
A
Rosano
C
C
Li
R
R
Harris
T
T
D000368:Aged; D000375:Aging / Q000502:physiology*; D000409:Alanine / Q000235:genetics*; D044383:Black People; D003072:Cognition Disorders / Q000235:genetics*; D005260:Female; D005838:Genotype; D006801:Humans; D008137:Longitudinal Studies; D008297:Male; D008609:Mental Status Schedule; D009483:Neuropsychological Tests; D047495:PPAR gamma / Q000235:genetics*; D011392:Proline / Q000235:genetics*; D012189:Retrospective Studies; D012306:Risk; D044465:White People
D047495:PPAR gamma; D011392:Proline; D000409:Alanine