PP456 - HOUSEHOLD DRINKING-WATER HARDNESS, MINERAL CONTENT, AND RISK OF DEMENTIA AND STROKE: A PROSPECTIVE COHORT STUDY IN THE UK BIOBANK

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PP456

HOUSEHOLD DRINKING-WATER HARDNESS, MINERAL CONTENT, AND RISK OF DEMENTIA AND STROKE: A PROSPECTIVE COHORT STUDY IN THE UK BIOBANK

G. Ding1, X. Liu1, Y. Li1, N. chen1,*, J. cui1

1Center of Cancer, The First Hospital of Jilin University, changchun, China

 

Rationale: Prospective evidence linking drinking-water hardness to stroke and dementia subtypes remains limited. We investigated associations of household water hardness and mineral content with incident stroke and dementia.

Methods: We analyzed 374,495 UK Biobank participants for dementia and 368,182 for stroke. Household water hardness (CaCO3), calcium, and magnesium were assigned from monitored data using USGS/WHO criteria. Incident events were ascertained through hospital and death records over median 12-year follow-up. Multivariable Cox models with restricted cubic splines assessed dose–response relationships.

Results: Compared with soft water (0–60 mg/L), hard (120–180 mg/L) and very hard water (>180 mg/L) were associated with 11% and 6% lower all-cause dementia risk (HR=0.89, 95% CI 0.81–0.99; HR=0.94, CI 0.85–0.98). Very hard water showed 15% lower total stroke risk (HR=0.85, P<0.001); WHO hard water showed 14% lower risk (HR=0.86, P<0.001). Protection was driven by ischemic stroke (18% and 16% lower risk; both P<0.001), with no associations for hemorrhagic subtypes. Per-SD increases in calcium and CaCO3 showed inverse stroke associations (HR≈0.94 and 0.93; both P<0.001). Vascular dementia showed stronger protection (27% lower risk with very hard water; HR=0.73, P<0.001) than Alzheimer's disease. Splines indicated non-linear, threshold-like relationships.

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Conclusion: Higher drinking-water hardness, calcium, and magnesium were associated with lower ischemic stroke and vascular dementia risks, supporting water mineral composition as a potential population-level determinant of cerebrovascular and neurocognitive health.

Disclosure of Interest: None declared