The effect of midlife physical activity on cognitive function among older adults: AGES--Reykjavik Study.
BACKGROUND
There are few studies on the long-term associations of physical activity (PA) to cognition. Here, we examine the association of midlife PA to late-life cognitive function and dementia.


METHODS
The sample consisted of a population-based cohort of men and women (born in 1907-1935) participating in the Age Gene/Environment Susceptibility-Reykjavik Study. The interval between the midlife ascertainment of PA and late-life cognitive function was 26 years. Composite scores of speed of processing, memory, and executive function were assessed with a battery of neuropsychological tests, and dementia was diagnosed according to international guidelines. There were 4,761 nondemented participants and 184 (3.7%) with a diagnosis of dementia, with complete data for the analysis.


RESULTS
Among the participants, no midlife PA was reported by 68.8%, ≤ 5 hours PA by 26.5%, and >5 hours PA by 4.5%. Excluding participants with dementia compared with the no PA group, both PA groups had significantly faster speed of processing (≤ 5 hours, β = .22; >5 hours, β = .32, p trend < .0001), better memory (≤ 5 hours, β = .15; >5 hours, β = .18, p trend < .0001), and executive function (≤ 5 hours, β = .09; >5 hours, β = .18, p trend< .0001), after controlling for demographic and cardiovascular factors. The ≤ 5 hours PA group was significantly less likely to have dementia in late life (odds ratio: 0.6, 95% confidence interval: 0.40-0.88) after adjusting for confounders.


CONCLUSIONS
Midlife PA may contribute to maintenance of cognitive function and may reduce or delay the risk of late-life dementia.
Chang
Milan
M
Laboratory of Epidemiology, Demography, and Biometry, National Institute on Aging, National Institutes of Health, 7201 Wisconsin Avenue, Bethesda, MD 20892-9205, USA.
Jonsson
Palmi V
PV
Snaedal
Jon
J
Bjornsson
Sigurbjorn
S
Saczynski
Jane S
JS
Aspelund
Thor
T
Eiriksdottir
Gudny
G
Jonsdottir
Maria K
MK
Lopez
Oscar L
OL
Harris
Tamara B
TB
Gudnason
Vilmundur
V
Launer
Lenore J
LJ
D000328:Adult; D000375:Aging / Q000502:physiology* / Q000523:psychology*; D000483:Alleles; D001057:Apolipoproteins E / Q000235:genetics*; D003071:Cognition / Q000502:physiology*; D015331:Cohort Studies; D003704:Dementia / Q000517:prevention & control*; D056344:Executive Function / Q000502:physiology; D005260:Female; D020022:Genetic Predisposition to Disease; D006579:Heterozygote; D006801:Humans; D008137:Longitudinal Studies; D008297:Male; D008568:Memory / Q000502:physiology; D008606:Mental Processes / Q000502:physiology; D008875:Middle Aged; D009043:Motor Activity / Q000502:physiology*; D009483:Neuropsychological Tests; D040242:Risk Reduction Behavior; D013997:Time Factors
D001057:Apolipoproteins E
Lancet Neurol. 2005 Nov;4(11):705-11
16239176
J Psychiatr Res. 1975 Nov;12(3):189-98
1202204
Psychophysiology. 2002 May;39(3):303-12
12212649
Med Sci Sports Exerc. 2004 Nov;36(11):1923-9
15514508
Ann Intern Med. 2006 Jan 17;144(2):73-81
16418406
Science. 1993 Aug 13;261(5123):921-3
8346443
Am J Epidemiol. 2008 Nov 15;168(10):1132-9
18836152
J Am Geriatr Soc. 2003 Mar;51(3):410-4
12588587
Am J Epidemiol. 2007 May 1;165(9):1076-87
17351290
Ann Intern Med. 1995 Jan 15;122(2):96-102
7993002
Res Q Exerc Sport. 2004 Jun;75(2):176-85
15209336
J Clin Psychiatry. 1998;59 Suppl 20:22-33;quiz 34-57
9881538
JAMA. 2004 Sep 22;292(12):1454-61
15383516
JAMA. 2008 Sep 3;300(9):1027-37
18768414
J Gerontol A Biol Sci Med Sci. 2003 Feb;58(2):176-80
12586857
Atherosclerosis. 2006 May;186(1):222-4
16445917
JAMA. 2004 Sep 22;292(12):1447-53
15383515
J Gerontol B Psychol Sci Soc Sci. 2007 Mar;62(2):P112-8
17379671
Med Sci Sports Exerc. 2001 May;33(5):772-7
11323547
JAMA. 1995 Dec 27;274(24):1915-21
8568984
J Clin Exp Neuropsychol. 2003 Aug;25(5):643-53
12815502
Dementia. 1994 Sep-Oct;5(5):266-81
7951684
Hippocampus. 2009 Oct;19(10):1030-9
19123237
J Int Neuropsychol Soc. 2002 Mar;8(3):448-60
11939702
Br J Sports Med. 2009 Jan;43(1):22-4
18927158
Am J Epidemiol. 2005 Apr 1;161(7):639-51
15781953
JAMA. 2002 Feb 13;287(6):742-8
11851541
Nat Rev Neurosci. 2008 Jan;9(1):58-65
18094706
Neurobiol Aging. 2005 Dec;26 Suppl 1:6-10
16246462
N Engl J Med. 2003 Jun 19;348(25):2508-16
12815136
J Gerontol A Biol Sci Med Sci. 2006 Nov;61(11):1157-65
17167156
Neurology. 1999 Jul 22;53(2):337-43
10430423
Am J Cardiol. 1991 Mar 15;67(7):633-9
2000798
Behav Brain Res. 2008 Sep 1;192(1):137-42
18378330