Water intake, hydration status and 2-year changes in cognitive performance: a prospective cohort study

Area of Science:

• Gerontology
• Neuroscience
• Nutritional Science

Background:

• Hydration status and water intake may influence cognitive function, but longitudinal data are scarce.
• This study investigated the long-term relationship between hydration and cognition in older adults at high cardiovascular risk.

Purpose of the Study:

• To longitudinally assess the association between hydration status and water intake with cognitive changes.
• To examine how hydration impacts cognitive performance in an older Spanish population.

Main Methods:

• Prospective analysis of 1957 adults (55-75 years) with overweight/obesity and metabolic syndrome.
• Hydration status assessed via serum osmolarity; cognitive function measured using a neuropsychological battery over 2 years.
• Multivariable linear regression models analyzed associations between baseline hydration, fluid intake, and cognitive changes.

Main Results:

• 56% of participants were physiologically dehydrated (serum osmolarity ≥ 300 mmol/L).
• Lower hydration status (higher serum osmolarity) correlated with a significant decline in global cognitive function z-score over 2 years (p=0.002).
• No significant association was found between water intake (from food/beverages) and cognitive changes.

Conclusions:

• Reduced physiological hydration is linked to greater cognitive decline in older adults with metabolic syndrome and overweight/obesity.
• Further research is needed to explore the long-term effects of hydration interventions on cognitive performance.