Change in risk of Alzheimer disease over time.
OBJECTIVE
To assess whether the risk of incidence of Alzheimer disease (AD) varies over time. The increase in numbers of people at the oldest ages in the population will bring an increase in the number of people with AD. Projections of the size of the increase assume the risk of AD is constant.


METHODS
All persons age 65 or older in a biracial, geographically defined area were invited to participate in a home interview every 3 years. From the approximately 10,000 participants, stratified random samples were selected for detailed clinical evaluation. At each cycle, individuals determined free of AD in a previous cycle, either by examination or by high score on cognitive function tests, were sampled in the subsequent cycle for evaluation for incident AD. The evaluations for disease were structured and uniform across time. These analyses include 1,695 subjects evaluated for incident disease from 1997 through 2008.


RESULTS
AD developed in 360 participants. Change over time in risk of incident disease was assessed in logistic regression analyses including evaluation date and controlling for age, gender, education, race, interval from disease-free designation to evaluation for incident disease, and sample design. The time variable (in years) was not significant (odds ratio = 0.970, 95% confidence interval = 0.902 to 1.044).


CONCLUSIONS
The null relation of evaluation date to disease incidence suggests no recent change in risk of AD over time, and supports this assumption for projections of AD.
Hebert
L E
LE
Rush Institute for Healthy Aging, 1645 W Jackson Blvd Suite 675, Chicago, IL 60612, USA. Liesi_Hebert@rush.edu
Bienias
J L
JL
Aggarwal
N T
NT
Wilson
R S
RS
Bennett
D A
DA
Shah
R C
RC
Evans
D A
DA
D000367:Age Factors; D000368:Aged; D000369:Aged, 80 and over; D000544:Alzheimer Disease / Q000175:diagnosis* / Q000453:epidemiology* / Q000208:ethnology / Q000235:genetics; D053327:Apolipoprotein E4 / Q000235:genetics; D044383:Black People; D002641:Chicago / Q000453:epidemiology; D015331:Cohort Studies; D005260:Female; D006801:Humans; D015994:Incidence; D008137:Longitudinal Studies; D008297:Male; D012307:Risk Factors; D012737:Sex Factors; D012959:Socioeconomic Factors; D013997:Time Factors; D044465:White People; D001741:Black or African American
D053327:Apolipoprotein E4
Acta Psychiatr Scand. 2007 Jan;115(1):73-9
17201869
J Gerontol B Psychol Sci Soc Sci. 1999 May;54(3):P155-60
10363036
J Alzheimers Dis. 2003 Oct;5(5):349-55
14646025
Neurology. 1991 Dec;41(12):1911-4
1745347
Am J Epidemiol. 1998 Jul 1;148(1):51-62
9663404
JAMA. 1995 May 3;273(17):1354-9
7715060
Neurology. 2004 Dec 28;63(12):2322-6
15623694
Stroke. 2006 May;37(5):1155-9
16601210
Psychosom Med. 2005 Nov-Dec;67(6):841-5
16314587
JAMA. 1998 Mar 11;279(10):751-5
9508150
Gerontology. 1994;40 Suppl 2:29-35
7926864
Alzheimer Dis Assoc Disord. 2001 Oct-Dec;15(4):169-73
11723367
Arch Psychiatr Nervenkr (1970). 1983;233(6):423-38
6667099
Adv Gerontol. 2005;16:30-7
16075674
Neurology. 1993 Oct;43(10):1887-92
8413943
JAMA. 2002 Feb 13;287(6):742-8
11851541
Neurology. 1984 Jul;34(7):939-44
6610841
Am J Public Health. 1998 Sep;88(9):1337-42
9736873
Neuropsychobiology. 1986;15(3-4):122-9
3785641
J Gerontol A Biol Sci Med Sci. 2004 Jul;59(7):762-6
15304542
Neuroepidemiology. 2005;25(4):181-91
16103729
Arch Neurol. 2003 Feb;60(2):185-9
12580702