Coffee and tea intake and long-term risk of dementia

Analysis of 2 large prospective cohorts with up to 43-year follow-up indicated that drinking more caffeinated coffee or tea, but not decaffeinated coffee, was associated with lower dementia risk and modestly better cognitive performance.

This summary is based on the publication of Zhang Y, Liu Y, Li Y, et al. - Coffee and Tea Intake, Dementia Risk, and Cognitive Function. JAMA. 2026 Feb 9:e2527259 [Online ahead of print]. doi: 10.1001/jama.2025.27259

Introduction and methods

Background

Multiple prospective studies have assessed the effect of coffee and caffeine intake on cognitive decline and the risk of dementia, but their results are inconsistent [1-5]. In addition, most studies did not differentiate between caffeinated and decaffeinated coffee and only had short follow-up periods [6].

Aim of the study

The study aim was to examine the associations of the long-term consumption of caffeinated coffee, decaffeinated coffee, or tea with dementia risk and cognitive function.

Methods

In a prospective cohort study, data were included from 86,606 female participants of the Nurses’ Health Study (NHS; 1980–2023) and 45,215 male participants of the Health Professionals Follow-up Study (1986–2023), both conducted in the US [7,8]. Exclusion criteria were cancer, Parkinson disease, and dementia at enrollment. Data on dietary intake of caffeinated coffee, decaffeinated coffee, and tea were collected at baseline and every 2–4 years thereafter using validated food frequency questionnaires. Median follow-up duration was 36.8 years (IQR: 28–42).

Outcomes

The primary endpoint was dementia, which was identified through death records and biennial self-reported physician diagnoses. Secondary endpoints included subjective cognitive decline based on a questionnaire-based score (range: 0–7, with higher scores indicating greater perceived decline; cases were defined as score ≥3). In NHS participants aged >70 years only, objective cognitive function was assessed, using 6 telephone-based neuropsychological tests such as the Telephone Interview for Cognitive Status (TICS) score (range: 0–41). Global cognition was based on a standardized mean z score for all 6 administered cognitive tests.

Main results

Dementia risk

• In a pooled analysis of both cohorts that was adjusted for potential confounders, a higher intake of caffeinated coffee was associated with a decreased risk of dementia during follow-up: Participants who drank the most caffeinated coffee (highest quartile) had an 18% lower dementia risk than those drinking the smallest amount of caffeinated coffee (lowest quartile) (incidence rate: 141 vs. 330 cases per 100,000 person-years; adjusted HR: 0.82; 95%CI: 0.76–0.89; P for trend<0.001).
• Similarly, increased consumption of tea was associated with lower dementia risk (highest vs. lowest tertile: 201 vs. 321 cases per 100,000 person-years; adjusted HR: 0.86; 95%CI: 0.83–0.90; P for trend<0.001).
• In contrast, decaffeinated coffee consumption was not associated with dementia risk over time (highest vs. lowest tertile: 262 vs. 259 cases per 100,000 person-years; adjusted HR: 0.97; 95%CI: 0.93–1.01; P for trend=0.34).

Subjective cognitive decline

• An adjusted pooled cohort analysis showed that a lower prevalence of subjective cognitive decline in the highest quartile of caffeinated coffee intake compared with the lowest quartile (7.8% vs. 9.5%; adjusted prevalence ratio: 0.85; 95%CI: 0.78–0.93; P for trend<0.001).
• For tea consumption, the highest tertile also had a lower prevalence of subjective cognitive decline than the lowest tertile (8.1% vs. 9.5%; adjusted prevalence ratio: 0.86; 95%CI: 0.80–0.93; P for trend<0.001).
• Conversely, decaffeinated coffee intake showed a positive association with the prevalence of subjective cognitive decline (highest vs. lowest tertile: 9.7% vs. 8.5%; adjusted prevalence ratio: 1.16; 95%CI: 1.08–1.24; P for trend<0.001).

Objective cognitive function

• In the NHS subgroup aged >70 years, higher caffeinated coffee intake was associated with a modestly better objective cognitive function. Participants in the highest quartile had a higher mean TICS score than those in the lowest quartile (adjusted mean difference: 0.11; 95%CI: 0.01–0.21; P for trend=0.03).
• However, drinking more caffeinated coffee was not associated with the mean global cognition score (adjusted mean difference between highest and lowest quartile: 0.02; 95%CI: –0.01 to 0.04; P for trend=0.06).
• Compared with the lowest tertile, the highest tertile of tea intake was associated with a higher TICS score (adjusted mean difference: 0.16; 95%CI: 0.08–0.25; P for trend=0.001) and a higher global cognition score (adjusted mean difference: 0.04; 95%CI: 0.02–0.06; P for trend<0.001).
• Decaffeinated coffee intake was not associated with better cognitive performance (for both tests: P for trend>0.05).

Dose-response analyses

• Dose-response analyses revealed nonlinear inverse associations between the intake of caffeinated coffee, tea, or caffeine (i.e., coffee, tea, soda, and chocolate) and both dementia risk and subjective cognitive decline.
• Daily consumption of approximately 2–3 cups of caffeinated coffee or 1–2 cups of tea was associated with the lowest risk of dementia compared with no consumption.

Conclusion

In this analysis of 2 large US prospective observational cohorts of predominantly health professionals with up to 43-year follow-up, greater consumption of caffeinated coffee or tea was associated with a reduced risk of dementia, a lower prevalence of subjective cognitive decline, and modestly better objective cognitive function (latter assessed in females only). The strongest associations were seen for moderate daily intake levels (i.e., 2–3 cups of caffeinated coffee or 1–2 cups of tea). Consumption of decaffeinated coffee was not associated with lower dementia risk or better cognitive performance.

The authors do note that the food frequency questionnaires “did not capture granular details regarding the specific type of tea consumed (e.g., green vs. black tea; caffeinated vs. decaffeinated tea) or specific coffee preparation methods (e.g., bean origin, roast level, or brewing technique). Variations in these factors can influence the concentration of caffeine and other bioactive compounds.”

Find this article online at JAMA.

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