Abstract
Background:
The implication of calcium and magnesium in drinking water for cardiovascular disease is unclear.
Objectives:
To assess the association of the concentration of calcium and magnesium in drinking water with incidence of myocardial infarction and stroke, accounting for dietary mineral intake.
Methods:
We linked drinking water monitoring data to residential information of 26,733 women from the population-based Swedish Mammography Cohort, who completed a 96-item food frequency questionnaire at baseline. Drinking water was categorized into low (magnesium <10 mg/L and calcium <50 mg/L) or high (magnesium ≥10 mg/L or calcium ≥50 mg/L) mineral concentration. Incident cases of myocardial infarction and stroke types were ascertained 1998-2019 using the National Patient Register.
Results:
Calcium and magnesium in drinking water was mean (± SD) 29 (±7) and 5 (±1) mg/L in the low and 52 (±20) and 10 (±3) mg/L in the high exposed areas, respectively. During 16 years of follow-up, we ascertained 2,023, 2,279 and 452 cases of myocardial infarction, ischemic and hemorrhagic stroke, respectively. High drinking water calcium and magnesium was associated with lower risk of ischemic and hemorrhagic stroke hazard ratios (HRs) 0.87 (95% confidence interval; CI: 0.80, 0.95) and 0.78 (95% CI: 0.65, 0.95), while the HR for myocardial infarction was 0.93 (95% CI: 0.85, 1.02). In separate analyses, only drinking water magnesium, not calcium, remained associated with ischemic stroke (HR: 0.69; 95% CI: 0.54, 0.88).
Conclusion:
Drinking water with a high concentration of calcium and magnesium, particularly magnesium, may lower the risk of stroke in postmenopausal women.
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