Why the study?
The study aimed to evaluate the association between domestic water hardness and incident AF, its interaction with genetic susceptibility, and secondary associations with incident HF, CHD, and stroke.
Does domestic water hardness of 121-180 mg/L reduce the incidence of AF, HF, CHD, and stroke compared to water hardness ≤ 60 mg/L in adults?
Does domestic water hardness of 121-180 mg/L reduce the incidence of AF, HF, CHD, and stroke compared to water hardness ≤ 60 mg/L in adults?
Domestic hard water (121-180 mg/L) is associated with a lower risk of incident atrial fibrillation, heart failure, coronary heart disease, and stroke compared to soft water, independent of genetic risk.
U-shaped water hardness–AF association observed; leaves open environmental modifier hypothesis independent of genetic risk, no practice implications yet.
AIMS: The study aimed to investigate the association between domestic water hardness and the incidence of AF and the interaction effects between water hardness and genetic susceptibility to incident AF risk. As a secondary objective, its associations with incident heart failure (HF), coronary heart disease (CHD), and stroke were measured. METHODS: concentration. The genetic risk score for AF was based on the standard polygenic risk score. Cox proportional hazards regression models and restricted cubic spline (RCS) analysis were conducted. RESULTS: During a median follow-up of 13.74 years, 30,726 (6.86%) individuals were diagnosed with AF for the first time. Compared with those with water hardness ≤ 60 mg/L, individuals with domestic water hardness 121-180 mg/L had a 17% lower risk of developing AF (HR 0.83, 95% CI 0.79-0.87), but water hardness of 61-120 mg/L and > 180 mg/L was associated with a higher risk of incident AF (both 1.04, 1.01-1.07). A non-linear relationship between water hardness and incident AF (P for non-linear = 0.001) was found. Individuals with water hardness 121-180 mg/L were also significantly associated with a lower risk of incident HF (HR 0.82, 95% CI 0.75-0.89), CHD (HR 0.80, 95% CI 0.76-0.84) and stroke (HR 0.88, 95% CI 0.81-0.95). There were no significant interaction effects between water hardness level and genetic susceptibility to AF, HF, CHD, and stroke risk (all P for interaction > 0.05). CONCLUSION: Potential U-shaped associations between domestic water hardness and incident AF across varying levels of genetic risk were found. Hard water (121-180 mg/L) may offer the most benefits compared to soft water when considering overall cardiovascular health, including AF, HF, CHD, and stroke.
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Tian et al. (2025) studied this question.
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