Natalia I Dmitrieva, Jonathan Rabinowitz, Eric S Leifer, Delong Liu, Mona N Bahouth, Manfred Boehm, Rebecca F Gottesman
Across both cohorts, with up to 30 years of follow-up, dementia risk showed a nonlinear association with hydration markers. Risk began increasing within the mid-normal range, around 141 mmol/L for serum sodium and 287 mosmol/kg for tonicity, reaching a 1.5- to 3-fold increase at the upper end and beyond.
INTRODUCTION: Identifying modifiable, accessible dementia risk factors is critical for prevention. Worldwide surveys indicate that about half of adults do not meet recommended fluid intake and may be chronically underhydrated.
METHODS: We examined associations between intracellular hydration markers and dementia risk in 13,535 participants from the Atherosclerosis Risk in Communities (ARIC) study and 395,802 individuals from Israel's Leumit Health Services. Serum sodium, glucose-corrected sodium, and tonicity were modeled using restricted cubic splines in adjusted Cox models of incident dementia.
RESULTS: Across both cohorts, with up to 30 years of follow-up, dementia risk showed a nonlinear association with hydration markers. Risk began increasing within the mid-normal range, around 141 mmol/L for serum sodium and 287 mosmol/kg for tonicity, reaching a 1.5- to 3-fold increase at the upper end and beyond.
DISCUSSION: These findings suggest hypertonic underhydration as early marker of dementia risk and support adequate water intake and glycemic control for dementia prevention.