Dairy Intake and Risk of Cognitive Decline and Dementia: A Systematic Review and Dose-Response Meta-Analysis of Prospective Studies

Fanny Villoz; Tommaso Filippini; Natalia Ortega; Doris Kopp-Heim; Trudy Voortman; Manuel R Blum; Cinzia Del Giovane; Marco Vinceti; Nicolas Rodondi; Patricia O Chocano-Bedoya

doi:10.1016/j.advnut.2023.100160

Dairy Intake and Risk of Cognitive Decline and Dementia: A Systematic Review and Dose-Response Meta-Analysis of Prospective Studies

Adv Nutr. 2024 Jan;15(1):100160. doi: 10.1016/j.advnut.2023.100160. Epub 2023 Dec 1.

Authors

Affiliations

¹ Institute of Primary Health Care (BIHAM), University of Bern, Bern, Switzerland; Department of General Internal Medicine, Inselspital, Bern University Hospital, University of Bern, Bern, Switzerland.
² Section of Public Health, Department of Biomedical, Metabolic and Neural Sciences, University of Modena and Reggio Emilia, Modena, Italy; School of Public Health, University of California Berkeley, Berkeley, CA, United States.
³ Institute of Primary Health Care (BIHAM), University of Bern, Bern, Switzerland; Population Health Laboratory, University of Fribourg, Fribourg, Switzerland.
⁴ Public Health and Primary Care Library, University Library of Bern, University of Bern, Bern, Switzerland.
⁵ Department of Epidemiology, Erasmus MC University Medical Center, Rotterdam, the Netherlands.
⁶ Institute of Primary Health Care (BIHAM), University of Bern, Bern, Switzerland; Population Health Laboratory, University of Fribourg, Fribourg, Switzerland; Department of Medical and Surgical Sciences for Children and Adults, University-Hospital of Modena and Reggio Emilia, Modena, Italy.
⁷ Section of Public Health, Department of Biomedical, Metabolic and Neural Sciences, University of Modena and Reggio Emilia, Modena, Italy; Department of Epidemiology, Boston University School of Public Health, Boston, MA, United States.
⁸ Institute of Primary Health Care (BIHAM), University of Bern, Bern, Switzerland; Population Health Laboratory, University of Fribourg, Fribourg, Switzerland. Electronic address: patricia.chocano@biham.unibe.ch.

Abstract

Dairy intake may influence cognition through several molecular pathways. However, epidemiologic studies yield inconsistent results, and no dose-response meta-analysis has been conducted yet. Therefore, we performed a systematic review with a dose-response meta-analysis about the association between dairy intake and cognitive decline or incidence of dementia. We investigated prospective studies with a follow-up ≥6 mo on cognitive decline or dementia incidence in adults without known chronic conditions through a systematic search of Embase, Medline, Cochrane Library, Web of Science, and Google Scholar from inception to 11 July 2023. We evaluated the dose-response association using a random-effects model. We identified 15 eligible cohort studies with >300,000 participants and a median follow-up of 11.4 y. We observed a negative nonlinear association between cognitive decline/dementia incidence and dairy intake as assessed through the quantity of consumption, with the nadir at ∼150 g/d (risk ratio: 0.88; 95% confidence interval: 0.78, 0.99). Conversely, we found an almost linear negative association when we considered the frequency of consumption (risk ratio for linear trend: 0.84; 95% confidence interval: 0.77, 0.92 for 1 time/d increase of dairy products). Stratified analysis by dairy products showed different shapes of the association with linear inverse relationship for milk intake, whereas possibly nonlinear for cheese. The inverse association was limited to Asian populations characterized by generally lower intake of dairy products, compared with the null association reported by European studies. In conclusion, our study suggests a nonlinear inverse association between dairy intake and cognitive decline or dementia, also depending on dairy types and population characteristics, although the heterogeneity was still high in overall and several subgroup analyses. Additional studies should be performed on this topic, including a wider range of intake and types of dairy products, to confirm a potential preventing role of dairy intake on cognitive decline and identify ideal intake doses. This review was registered at PROSPERO as CRD42020192395.

Keywords: cognitive decline; cohort studies; dairy products; dementia; dose-response meta-analysis.

Publication types

Systematic Review
Meta-Analysis
Review

MeSH terms

Animals
Cognitive Dysfunction* / epidemiology
Cognitive Dysfunction* / etiology
Cognitive Dysfunction* / prevention & control
Dairy Products
Dementia* / epidemiology
Dementia* / prevention & control
Diet
Humans
Milk
Prospective Studies
Risk Factors