Does being dehydrated relate to faster cognitive decline?
In 1957 PREDIMED-Plus adults, higher baseline serum osmolarity tracked greater 2-year global cognitive decline, while reported water intake did not.
Source
Water intake, hydration status and 2-year changes in cognitive performance: a prospective cohort study
Study at a glance
- Design
- Cohort — Prospective PREDIMED-Plus analysis of baseline hydration vs 2-year cognition change
- N
- N=1957 · Adults 55–75 with overweight/obesity and metabolic syndrome
- Population
- Older Spanish PREDIMED-Plus participants at high CVD risk
- Outcome
- 2-year change in global cognitive function z-score
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Does being dehydrated relate to faster cognitive decline?
These passages occur verbatim in the stored paper text. They support the points listed below; they do not verify every statement in the explanation.
1957 adults analyzed from PREDIMED-Plus.
A prospective analysis was conducted of a cohort of 1957 adults (aged 55–75)
56% physiologically dehydrated; osmolarity–cognition β −0.010.
Serum osmolarity (mean 298 ± 24 mmol/L, range 263 to 347 mmol/L) indicated that 56% of participants were physiologically dehydrated.
What they did
Prospectively related baseline serum osmolarity categories and beverage/food water intake (vs EFSA adequacy) to 2-year change in a composite cognition z-score from eight neuropsychological tests, using multivariable linear models.
What they found
Mean total water intake 2871 mL/day; 80.2% met EFSA adequacy, yet 56% were physiologically dehydrated by osmolarity (mean 298 mmol/L). Greater osmolarity associated with worse cognitive change (β −0.010; 95% CI −0.017 to −0.004). Water intake from foods/beverages was not significantly associated with cognitive change.
The limits
What it doesn't show
Observational 2-year follow-up cannot prove that drinking more water prevents dementia; osmolarity may proxy broader illness/medication factors.
Key terms
- Serum osmolarity
- Blood concentration measure used here as hydration status.
- Physiological dehydration
- Osmolarity ≥300 mmol/L in this study’s categories.
- PREDIMED-Plus
- Spanish lifestyle trial cohort of adults with metabolic syndrome.
- Global cognitive z-score
- Composite summarizing multiple validated cognitive tests.
- EFSA water AI
- European Food Safety Authority adequate intake references.
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Common questions
Sample?
1957 adults aged 55–75.
Key exposure?
Serum osmolarity (hydration status).
Main finding?
Higher osmolarity → greater 2-year cognitive decline.
Did intake predict cognition?
No significant association for water intake.