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Tea Consumption Is Associated with Reduced Cognitive Decline and Interacts with Iron Intake: A Population-Based Longitudinal Study on 4,820 Old Adults

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Journal of Alzheimer's Disease
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Background Previous studies suggest a positive effect of tea intake on cognition. Additional micronutrients that may moderate this association was not previously examined. Objective To examine the association between tea consumption and cognition and explore the interaction between tea consumption and iron intake. Methods Data from the China Health and Nutrition Survey between 1997 and 2011 was used. 4,820 individuals (≥55 years) were included in the analyses. Measurement of cognitive function was conducted in 1997, 2000, 2004, and 2006. Tea consumption was self-reported. Food intake was assessed by 24-hour dietary recalls of three consecutive days during home visits between 1997 and 2011. Multivariable mixed linear regression and logistic regression was used to assess the association. Results Tea consumption was associated with reduced global cognitive function decline. In fully adjusted models, regression coefficients (95% CIs) for those who consumed 0 cups/day,<2 cups/day, 2–3.9 cups/day, and≥4 cups/day of tea were 0, –0.09 (–0.55–0.37), 0.05 (–0.34–0.45), and 0.87 (0.46–1.29), respectively. This effect was stronger in adults > 60 years. Tea consumption of≥4 cups/day was inversely associated with self-reported poor memory (OR 0.70 (95% CI 0.56–0.86)) and memory decline (OR, 0.73 (95% CI 0.62–0.87)). There was a significant interaction between tea consumption and iron intake in relation to cognition. High iron intake was inversely associated with cognition in non-consumers of tea but not in tea consumers. Conclusion Higher tea intake is associated with reduced cognitive decline in adults and inhibits the adverse effect of high iron intake.
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Journal of Alzheimer’s Disease 90 (2022) 271–282
DOI 10.3233/JAD-220344
IOS Press
271
Tea Consumption Is Associated with
Reduced Cognitive Decline and Interacts
with Iron Intake: A Population-Based
Longitudinal Study on 4,820 Old Adults
Layan Sukika, Jianghong Liuband Zumin Shia,c,
aDepartment of Human Nutrition, College of Health Sciences, QU Health, Qatar University, Doha, Qatar
bUniversity of Pennsylvania School of Nursing, Philadelphia, PA, USA
cBiomedical and Pharmaceutical Research Unit, QU Health, Qatar University, Doha, Qatar
Accepted 15 August 2022
Pre-press 12 September 2022
Abstract.
Background: Previous studies suggest a positive effect of tea intake on cognition. Additional micronutrients that may
moderate this association was not previously examined.
Objective: To examine the association between tea consumption and cognition and explore the interaction between tea
consumption and iron intake.
Methods: Data from the China Health and Nutrition Survey between 1997 and 2011 was used. 4,820 individuals (55
years) were included in the analyses. Measurement of cognitive function was conducted in 1997, 2000, 2004, and 2006.
Tea consumption was self-reported. Food intake was assessed by 24-hour dietary recalls of three consecutive days during
home visits between 1997 and 2011. Multivariable mixed linear regression and logistic regression was used to assess the
association.
Results: Tea consumption was associated with reduced global cognitive function decline. In fully adjusted models, regression
coefficients (95% CIs) for those who consumed 0 cups/day,<2 cups/day, 2–3.9 cups/day, and4 cups/day of tea were 0,
–0.09 (–0.55–0.37), 0.05 (–0.34–0.45), and 0.87 (0.46–1.29), respectively. This effect was stronger in adults > 60 years. Tea
consumption of 4 cups/day was inversely associated with self-reported poor memory (OR 0.70 (95% CI 0.56–0.86)) and
memory decline (OR, 0.73 (95% CI 0.62–0.87)). There was a significant interaction between tea consumption and iron intake
in relation to cognition. High iron intake was inversely associated with cognition in non-consumers of tea but not in tea
consumers.
Conclusion: Higher tea intake is associated with reduced cognitive decline in adults and inhibits the adverse effect of high
iron intake.
Keywords: Adults, Chinese, cognition, iron intake, tea consumption
Correspondence to: Zumin Shi, MD, PhD, Human Nutrition
Department, College of Health Sciences, QU Health, Qatar Uni-
versity, P.O. Box 2713 Doha, Qatar. Tel.: +974 4403 6037; Fax:
+974 4403 4801; E-mail: zumin@qu.edu.qa.
INTRODUCTION
Dementia is a general term for cognitive decline
that is known to affect the quality of life, especially
among the elderly population. Cognition-related
diseases such as mild cognitive impairment and
Alzheimer’s disease (AD) are gradually increasing
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