BMJ Glob Health. 2025 Dec 10;10(12):e018543. doi: 10.1136/bmjgh-2024-018543.
ABSTRACT
BACKGROUND: The link between drinking water salinity and increased blood pressure and hypertension risk among coastal and other populations remains unclear. To investigate this, we performed a systematic review and meta-analysis of observational studies on drinking water salinity and cardiovascular outcomes.
METHODS: We systematically searched MEDLINE, Embase and Web of Science for relevant studies published until 10 May 2025. Observational studies reporting on the association between sodium in drinking water and systolic/diastolic blood pressure (SBP/DBP), hypertension, coronary heart disease (CHD), stroke and composite cardiovascular outcomes were prespecified to be included. We assessed study quality using the Newcastle-Ottawa Scale and performed random effects meta-analysis.
RESULTS: We identified 27 observational studies (involving 74 063 unique participants from 7 countries), 15 of which included coastal populations. Comparing higher versus lower drinking water salinity, the mean differences were 3.22 mm Hg (95% CI 1.11 to 5.33) for SBP and 2.82 mm Hg (95% CI 1.44 to 4.20) for DBP. The pooled OR for hypertension, comparing higher versus lower water salinity, was 1.26 (95% CI 1.07 to 1.48). These associations were generally consistent across subgroups but were statistically significant for studies conducted in coastal populations and for those published after 2000. However, we found an insufficient number of studies with reliable data on CHD or stroke outcomes.
CONCLUSIONS: Higher drinking water salinity is associated with an elevated risk of blood pressure and hypertension, especially among coastal populations. More research is needed to examine connections with CHD and stroke, and to create strategies to counter salinity's effects, particularly in climate-vulnerable coastal areas.
PMID:41371925 | DOI:10.1136/bmjgh-2024-018543