Occupational Attainment as Risk Factor for Progression from Mild Cognitive Impairment to Alzheimer's Disease: A CREDOS Study.
High occupational attainment has been known as a marker of cognitive reserve. Previous studies in the general population have shown that high occupational attainment is associated with reduced risk of Alzheimer's disease (AD). However, few studies have assessed the effect of occupational attainment on the clinical course of mild cognitive impairment (MCI). In this study, we evaluated whether individuals with high occupational attainment show more frequent progression from MCI to AD. Participants (n = 961) with MCI were recruited from a nationwide, hospital-based multi-center cohort, and were followed for up to 60 months (median: 17.64, interquartile range [12.36, 29.28]). We used Cox regression for competing risks to analyze the effect of occupational attainment on development of AD, treating dementia other than AD as a competing risk. Among the 961 individuals with MCI, a total of 280 (29.1%) converted to dementia during the follow-up period. The risk of progression to AD was higher in the individuals with high occupational attainment after controlling for potential confounders (hazard ratio = 1.83, 95% confidence interval = 1.25-2.69, p = 0.002). High occupational attainment in individuals with MCI is an independent risk factor for higher progression rate of MCI to AD. This result suggests that the protective effect of high occupational attainment against cognitive decline disappears in the MCI stage, and that careful assessment of occupational history can yield important clinical information for prognosis in individuals with MCI.
Department of Psychiatry, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Korea.
Woojae
W
Myung
Department of Psychiatry, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Korea.
Chunsoo
C
Lee
Department of Psychiatry, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Korea.
Jin Hong
JH
Park
Biostatistical Team, Samsung Biomedical Research Institute, Seoul, Korea.
Sook-Young
SY
Woo
Biostatistical Team, Samsung Biomedical Research Institute, Seoul, Korea.
Seonwoo
S
Kim
Department of Psychiatry, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Korea.
Sangha
S
Kim
Department of Psychiatry, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Korea.
Jae Won
JW
Chung
Center for Clinical Research, Samsung Biomedical Research Institute, Seoul, Korea.
Hyo Shin
HS
Kang
Department of Psychiatry, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Korea.|Center for Clinical Research, Samsung Biomedical Research Institute, Seoul, Korea.
Shinn-Won
SW
Lim
Department of Psychiatry, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Korea.
Junbae
J
Choi
Department of Neurology, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Korea.
Duk L
DL
Na
Department of Psychiatry, Asan Medical Center, University of Ulsan College of Medicine, Seoul, Korea.
Seong Yoon
SY
Kim
Department of Neurology, Asan Medical Center, University of Ulsan College of Medicine, Seoul, Korea.
Jae-Hong
JH
Lee
Department of Neurology, Konkuk University School of Medicine, Seoul, Korea.
Seol-Heui
SH
Han
Department of Neurology, Inha University School of Medicine, Incheon, Korea.
Seong Hye
SH
Choi
Department of Neurology, Seoul National University College of Medicine, Seoul, Korea.
Sang Yun
SY
Kim
Pacific Behavioral Research Foundation, Carmel, CA, USA.
Bernard J
BJ
Carroll
Department of Psychiatry, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Korea.
Doh Kwan
DK
Kim
D000368:Aged; D000544:Alzheimer Disease / Q000453:epidemiology* / Q000503:physiopathology* / Q000523:psychology; D060825:Cognitive Dysfunction / Q000453:epidemiology* / Q000503:physiopathology* / Q000523:psychology; D058245:Cognitive Reserve; D018450:Disease Progression; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D015994:Incidence; D008137:Longitudinal Studies; D008297:Male; D015999:Multivariate Analysis; D009790:Occupations; D016016:Proportional Hazards Models; D012307:Risk Factors
Alzheimer’s disease; mild cognitive impairment; occupational attainment; progression