Prevalence and population attributable fractions of potentially modifiable risk factors for dementia in Canada: A cross-sectional analysis of the Canadian Longitudinal Study on Aging

Yasaman Dolatshahi; Alexandra Mayhew; Megan E O'Connell; Teresa Liu-Ambrose; Vanessa Taler; Eric E Smith; David B Hogan; Susan Kirkland; Andrew P Costa; Christina Wolfson; Parminder Raina; Lauren Griffith; Aaron Jones

doi:10.17269/s41997-024-00920-7

Prevalence and population attributable fractions of potentially modifiable risk factors for dementia in Canada: A cross-sectional analysis of the Canadian Longitudinal Study on Aging

Can J Public Health. 2024 Dec;115(6):953-963. doi: 10.17269/s41997-024-00920-7. Epub 2024 Jul 24.

Authors

Yasaman Dolatshahi¹, Alexandra Mayhew^{1

2

3}, Megan E O'Connell⁴, Teresa Liu-Ambrose^{5

6

7}, Vanessa Taler^{8

9}, Eric E Smith¹⁰, David B Hogan¹¹, Susan Kirkland¹², Andrew P Costa^{1

2}, Christina Wolfson^{13

14}, Parminder Raina^{1

2

3}, Lauren Griffith^{1

2

3}, Aaron Jones^{15

16}

Affiliations

¹ Department of Health Research Methods, Evidence, and Impact, McMaster University, Hamilton, ON, Canada.
² McMaster Institute for Research on Aging, Hamilton, ON, Canada.
³ Labarge Centre for Mobility in Aging, Hamilton, ON, Canada.
⁴ Department of Psychology & Health Studies, University of Saskatchewan, Saskatoon, SK, Canada.
⁵ Department of Physical Therapy, University of British Columbia, Vancouver, BC, Canada.
⁶ Centre for Aging, SMART at Vancouver Coastal Health, Vancouver Coastal Health Research Institute, Vancouver, BC, Canada.
⁷ Djavad Mowafaghian Centre for Brain Health, Vancouver Coastal Health Research Institute, Vancouver, BC, Canada.
⁸ School of Psychology, University of Ottawa, Ottawa, ON, Canada.
⁹ Bruyère Research Institute, Ottawa, ON, Canada.
¹⁰ Department of Clinical Neurosciences and Hotchkiss Brain Institute, University of Calgary, Calgary, AB, Canada.
¹¹ Division of Geriatric Medicine and Hotchkiss Brain Institute, Cumming School of Medicine, University of Calgary, Calgary, AB, Canada.
¹² Department of Community Health & Epidemiology and Division of Geriatric Medicine, Dalhousie University, Halifax, NS, Canada.
¹³ Department of Epidemiology, Biostatistics and Occupational Health, School of Population and Global Health & Department of Medicine, McGill University, Montreal, QC, Canada.
¹⁴ Research Institute of the McGill University Health Centre, Montreal, QC, Canada.
¹⁵ Department of Health Research Methods, Evidence, and Impact, McMaster University, Hamilton, ON, Canada. jonesa13@mcmaster.ca.
¹⁶ McMaster Institute for Research on Aging, Hamilton, ON, Canada. jonesa13@mcmaster.ca.

Abstract
in English, French

Objectives: We investigated the prevalence and population attributable fraction (PAF) of 12 potentially modifiable risk factors for dementia in middle-aged and older Canadians.

Methods: We conducted a cross-sectional study of 30,097 adults aged 45 to 85 with baseline data from the Canadian Longitudinal Study on Aging (2011‒2015). Risk factors and associated relative risks were taken from a highly cited systematic review. We calculated the prevalence of each risk factor using sampling weights. Individual PAFs were calculated both crudely and weighted for communality, and combined PAFs were calculated using both multiplicative and additive assumptions. Analyses were stratified by household income and repeated at CLSA's first follow-up (2015‒2018).

Results: The most prevalent risk factors were physical inactivity (63.8%; 95% CI, 62.8-64.9), hypertension (32.8%; 31.7-33.8), and obesity (30.8%; 29.7-31.8). The highest crude PAFs were physical inactivity (19.9%), traumatic brain injury (16.7%), and hypertension (16.6%). The highest weighted PAFs were physical inactivity (11.6%), depression (7.7%), and hypertension (6.0%). We estimated that the 12 risk factors combined accounted for 43.4% (37.3‒49.0) of dementia cases assuming weighted multiplicative interactions and 60.9% (55.7‒65.5) assuming additive interactions. There was a clear gradient of increasing prevalence and PAF with decreasing income for 9 of the 12 risk factors.

Conclusion: The findings of this study can inform individual- and population-level dementia prevention strategies in Canada. Differences in the impact of individual risk factors between this study and other international and regional studies highlight the importance of tailoring national dementia strategies to the local distribution of risk factors.

RéSUMé: OBJECTIFS: Nous avons étudié la prévalence et la fraction attribuable dans la population (FAP) de 12 facteurs de risque de démence potentiellement modifiables chez les Canadiens d’âge moyen et plus âgés. MéTHODE: Nous avons mené une étude transversale de 30 097 adultes de 45 à 85 ans à l’aide des données de référence de l’Étude longitudinale canadienne sur le vieillissement (ELCV) (2011‒2015). Les facteurs de risque et les risques relatifs associés ont été extraits d’une revue systématique fréquemment citée. Nous avons calculé la prévalence de chaque facteur de risque à l’aide de poids d’échantillonnage. Les FAP individuelles ont été calculées à la fois sous forme brute et pondérées selon leurs points communs; les FAP combinées ont été calculées à l’aide d’hypothèses multiplicatives et additives. Les analyses ont été stratifiées selon le revenu du ménage et répétées au premier suivi de l’ELCV (2015‒2018). RéSULTATS: Les facteurs de risque les plus prévalents étaient la sédentarité (63,8 %; IC de 95%, 62,8–64,9), l’hypertension artérielle (32,8 %; 31,7–33,8) et l’obésité (30,8 %; 29,7–31,8). Les FAP brutes les plus élevées étaient la sédentarité (19,9 %), les traumatismes cranio-cérébraux (16,7 %) et l’hypertension artérielle (16,6 %). Les FAP pondérées les plus élevées étaient la sédentarité (11,6 %), la dépression (7,7 %) et l’hypertension artérielle (6,0 %). Selon nos estimations, les 12 facteurs de risque combinés représentaient 43,4 % (37,3‒49,0) des cas de démence en supposant des interactions multiplicatives pondérées et 60,9 % (55,7‒65,5) en supposant des interactions additives. Il y avait clairement un gradient d’accroissement de la prévalence et de la FAP avec la diminution du revenu pour 9 des 12 facteurs de risque. CONCLUSION: Les constats de l’étude peuvent éclairer les stratégies individuelles et populationnelles de prévention de la démence au Canada. Les différences d’impact des facteurs de risque individuels entre cette étude et d’autres études internationales et régionales montrent l’importance d’adapter les stratégies nationales de prévention de la démence à la répartition locale des facteurs de risque.

Keywords: Dementia; Population health; Risk factors; Social determinants of health.

MeSH terms

Aged
Aged, 80 and over
Canada / epidemiology
Cross-Sectional Studies
Dementia* / epidemiology
Female
Humans
Hypertension / epidemiology
Longitudinal Studies
Male
Middle Aged
Prevalence
Risk Factors
Sedentary Behavior

Abstract in English, French

MeSH terms

Abstract
in English, French