A large prospective cohort study utilizing UK Biobank data found significant associations between coffee and tea consumption and dementia risk, particularly in individuals with hypertension. The study, published in Scientific Reports, analyzed data from 453,913 participants over an average follow-up period of 15.12 years.
Key Findings:
- Among coffee drinkers, hypertensive individuals consuming 0.5-1 cup of coffee daily had the lowest risk of all-cause dementia (HR = 0.733, 95% CI 0.613-0.875).
- Among tea drinkers, hypertensive individuals drinking 4-5 cups of tea daily had the lowest risk of all-cause dementia (HR = 0.744, 95% CI 0.675-0.887).
- A U-shaped relationship was observed between daily caffeine intake and the risk of all-cause and vascular dementia in hypertensive individuals.
- Ground coffee consumption was associated with the lowest risk of all-cause dementia and vascular dementia compared to other coffee types.
Methods:
Researchers utilized data from the UK Biobank, which recruited participants aged 39-74 between 2006 and 2010. Baseline information on coffee and tea consumption was collected through Food Frequency Questionnaires. Hypertension was defined as self-reported diagnosis, use of antihypertensive medication, or measured blood pressure ≥140/90 mmHg.
Dementia outcomes were identified using health-related outcomes defined by the UK Biobank preprocessing algorithm, based on primary care, hospitalization, and death registry data. Cox proportional hazard regression models were used to compute hazard ratios and 95% confidence intervals for the association between coffee or tea consumption and dementia risk.
Results:
Out of 453,913 participants, 54.62% had hypertension. The average age was 72.39 ± 8.11 years, with 54.33% being female and 94.13% being white. During follow-up, the hypertensive population had a higher incidence of all-cause dementia (3.11% vs. 1.11%), Alzheimer's disease (1.37% vs. 0.50%), and vascular dementia (0.76% vs. 0.18%) compared to those without hypertension.
After adjusting for sociodemographic characteristics, lifestyle factors, health-related issues, and serum markers, the study found:
- Coffee consumption and dementia risk:
- J-shaped relationship in hypertensive individuals
- Lowest risk at 0.5-1 cup daily (HR = 0.733, 95% CI 0.613-0.875)
- No significant association in non-hypertensive individuals
- Tea consumption and dementia risk:
- U-shaped relationship in hypertensive individuals
- Lowest risk at 4-5 cups daily (HR = 0.744, 95% CI 0.675-0.887)
- No significant association in non-hypertensive individuals
- Interaction of coffee and tea consumption:
- Significant association with all-cause dementia and Alzheimer's disease risk in hypertensive individuals
- Consuming 4-5 cups of coffee and ≥6 cups of tea daily is associated with lowest risk of all-cause dementia (HR = 0.541, 95% CI 0.311-0.939) and Alzheimer's disease (HR = 0.294, 95% CI 0.094-0.921)
- Coffee type and dementia risk:
- Ground coffee associated with lowest risk of all-cause dementia [(HR = 0.762, 95% CI 0.618-0.940) for non-hypertensive population and (HR = 0.682, 95% CI 0.588-0.791) for hypertensive population] and vascular dementia [(HR = 0.421, 95% CI 0.246-0.721) for non-hypertensive population and (HR = 0.655, 95% CI 0.478-0.898) for hypertensive population] compared to decaffeinated coffee
- Caffeine intake and dementia risk:
- U-shaped association with all-cause and vascular dementia risk in hypertensive individuals
- Quintile 2 of daily caffeine intake is associated with the lowest risk of all-cause dementia (HR = 0.764, 95% CI 0.669-0.872) and vascular dementia (HR = 0.596, 95% CI 0.446-0.798)
Subgroup analyses revealed stronger associations in hypertensive patients aged over 65, males, and those with higher socioeconomic status. The study found no statistically significant association between the temperature of hot beverages consumed and dementia risk.
Additional Data:
- The average follow-up time was 15.12 years.
- 58.10% of participants were employed, 7.66% were unemployed, and 33.30% were retired.
- 32.32% of participants had a college or university degree.
- 42.35% of participants had a BMI between 25-29.9 kg/m².
- 54.59% of participants were never smokers, 34.63% were previous smokers, and 10.41% were current smokers.
- 23.57% of participants were APOE ε4 carriers.
- 17.35% of participants were using lipid-lowering medications.
The researchers conducted several sensitivity analyses to test the robustness of their findings. These included excluding participants who developed dementia within 2 years, excluding outliers in coffee and tea consumption, excluding participants with a history of stroke at baseline, and accounting for weight reduction and grip strength to consider the potential impact of frailty on dementia.
Limitations:
The study authors noted several limitations, including potential information bias from self-reported coffee and tea consumption, the possibility of unmeasured confounding factors, and the predominantly white UK population limiting generalizability to other demographics.
The authors declared no competing interests.