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Association of drinking water salinity with elevated blood pressure and risk of hypertension among coastal and other populations: a systematic review and meta-analysis of observational studies

Rajat Das Gupta, S. Kunutsor, David Eliecer Lopez-Salamanca, Fariha Tahsin Mercy, N. Nawal, C. Tejada, Kunihiro Matsushita, Silvana Luciani et al.

BMJ Global Health, 2025

74 participants · 3 citations

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…

How strong is the evidence?

Evidence Hub reads this as a meta-analysis. Its evidence level is 1 of 5 (Highest · pooled evidence). Pooled evidence from several studies sits at the top of the evidence pyramid. Reported size: 74 participants or records.

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