Dementia incidence and population-attributable fraction for dementia risk factors in Republic of Korea: a 12-year longitudinal follow-up study of a national cohort

Song Hwangbo; Jin Young Lee; Gyule Han; Min Young Chun; Hyemin Jang; Sang Won Seo; Duk L Na; Sungho Won; Hee Jin Kim; Dong Hui Lim

doi:10.3389/fnagi.2023.1126587

Dementia incidence and population-attributable fraction for dementia risk factors in Republic of Korea: a 12-year longitudinal follow-up study of a national cohort

Front Aging Neurosci. 2023 Jul 13:15:1126587. doi: 10.3389/fnagi.2023.1126587. eCollection 2023.

Authors

Song Hwangbo^#^{1

2}, Jin Young Lee^#³, Gyule Han⁴, Min Young Chun⁵, Hyemin Jang^{1

6}, Sang Won Seo^{1

2

6}, Duk L Na^{1

2}, Sungho Won⁷, Hee Jin Kim^{1

2

6}, Dong Hui Lim^{4

8}

Affiliations

¹ Department of Neurology, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Republic of Korea.
² Alzheimer's Disease Convergence Research Center, Samsung Medical Center, Seoul, Republic of Korea.
³ Department of Statistics, Chung-Ang University, Seoul, Republic of Korea.
⁴ Department of Ophthalmology, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Republic of Korea.
⁵ Department of Neurology, Yongin Severance Hospital, Yonsei University Health System, Yongin-si, Republic of Korea.
⁶ Department of Health Sciences and Technology, SAIHST, Sungkyunkwan University, Seoul, Republic of Korea.
⁷ Department of Public Health Sciences, Seoul National University, Seoul, Republic of Korea.
⁸ Samsung Advanced Institute for Health Sciences and Technology (SAIHST), Sungkyunkwan University, Seoul, Republic of Korea.

^# Contributed equally.

Abstract

Background: We aimed to investigate the incidence of dementia by age and year as well as the population-attributable fractions (PAFs) for known dementia risk factors in Republic of Korea.

Methods: A 12-year, nationwide, population-based, retrospective cohort study was conducted. We used customized health information from the National Health Insurance Service (NHIS) data from 2002 to 2017. We analyzed age- and sex-adjusted incidence rates and PAF of dementia for each risk factor such as depression, diabetes, hemorrhagic stroke, ischemic stroke, hypertension, osteoporosis and physical inactivity using Levin's formula.

Results: Of the 794,448 subjects in the dementia-free cohort, 49,524 (6.2%) developed dementia. Dementia incidence showed annual growth from 1.56 per 1,000 person-years in 2006 to 6.94 per 1,000 person-years in 2017. Of all dementia cases, 34,544 subjects (69.8%) were female and 2,479 subjects (5.0%) were early onset dementia. AD dementia accounted for 66.5% of the total dementia incidence. Considering relative risk and prevalence, physical inactivity attributed the greatest to dementia (PAF, 8.1%), followed by diabetes (PAF, 4.2%), and hypertension (PAF, 2.9%). Altogether, the significant risk factors increased the risk of dementia by 18.0% (overall PAF).

Conclusion: We provided the incidence of dementia and PAFs for dementia risk factors in Republic of Korea using a 12-year, nationwide cohort. Encouraging lifestyle modifications and more aggressive control of risk factors may effectively prevent dementia.

Keywords: Alzheimer’s disease dementia; dementia; national cohort; population-attributable fraction; risk factor.

Grants and funding

This work was supported by a grant from the Korea Health Technology R&D Project through the Korea Health Industry Development Institute (KHIDI) funded by the Ministry of Health & Welfare, Republic of Korea (HU21C0111), the MSIT (Ministry of Science and ICT), Republic of Korea, under the ICT Creative Consilience program (IITP-2023-2020-0-01821), supervised by the IITP (Institute for Information & Communications Technology Planning & Evaluation), and the National Research Foundation of Korea grant funded by the Korean Government’s Ministry of Education (NRF-2021R1C1C1007795, Seoul, Republic of Korea).