Consequences of access to water from managed aquifer recharge systems for blood pressure and proteinuria in south-west coastal Bangladesh: a stepped-wedge cluster-randomized trial

Abstract

Background Drinking-water salinity has been associated with high blood pressure (BP) among communities in south-west coastal Bangladesh. We evaluated whether access to water from managed aquifer recharge (MAR)—a hydrogeological intervention to lower groundwater salinity by infiltrating rainwater into the aquifers—can reduce community BP. Methods We conducted a stepped-wedge cluster-randomized trial with five monthly visits between December 2016 and April 2017 in 16 communities. At each visit following baseline, four communities were randomized to access MAR water. Systolic BP was the primary outcome, measured during each visit using Omron® HEM–907 devices. We also measured participants’ 24-hour urinary sodium and households’ drinking- and cooking-water salinity each visit. We used multilevel regression models to estimate the effects of MAR-water access on participants’ BP. The primary analysis was intention-to-treat. Results In total, 2911 person-visits were conducted in communities randomized to have MAR-water access and 2834 in communities without MAR-water access. Households without MAR-water access predominantly used low-salinity pond water and 42% (range: 26–50% across visits) of households exclusively consumed MAR water when access was provided. Communities randomized to MAR-water access had 10.34 [95% confidence interval (CI): 1.11, 19.58] mmol/day higher mean urinary sodium, 1.96 (95% CI: 0.66, 3.26; p = 0.004) mmHg higher mean systolic BP and 1.44 (95% CI: 0.40, 2.48; p = 0.007) mmHg higher mean diastolic BP than communities without MAR-water access. Conclusions Our findings do not support the scale-up of MAR systems as a routine drinking-water source, since communities that shifted to MAR water from the lower-salinity pond-water source had higher urinary sodium and BP.

Urinary Sodium Excretion and Blood Pressure Relationship across Methods of Evaluating the Completeness of 24-h Urine Collections

“…High sweat flow may overwhelm the ability to reabsorb sodium from sweat. Therefore, sweating can potentially lead to decreased urinary sodium excretion, particularly for men, who may not have been fully acclimatized during the study [23]. Hence, bias due to sodium excretion in sweat may also have influenced our analyses.…”

“…The first cohort study followed up 383 participants for two visits (742 person-visits) from southwest coastal Bangladesh during the wet season [21]. The second study was a population-based stepped-wedge randomized controlled trial in southwest coastal Bangladesh that followed up 1190 participants for five monthly visits (5745 person-visits) during the dry season [22,23]. The third cohort study followed up 293 participants from southwest coastal and 277 from non-coastal central Bangladesh for seven visits covering both wet and dry seasons (3547 person-visits data: 1773 from coastal and 1774 from non-coastal regions) [24].…”

Spot Urine Formulas to Estimate 24-Hour Urinary Sodium Excretion Alter the Dietary Sodium and Blood Pressure Relationship

“… 20 The second study was a population-based stepped-wedge randomized controlled trial in southwest coastal Bangladesh that followed up 1190 participants for 5 monthly visits (5745 person-visits) to investigate the health effects of providing access to low-salinity groundwater. 21 , 22 The third cohort study followed up 293 participants from southwest coastal and 277 from noncoastal central Bangladesh for 7 visits (3547 person-visit data: 1773 from coastal and 1774 from noncoastal regions).…”

Associations between climate variables and water quality in low- and middle-income countries: A scoping review

“…This is gaining increasing attention in countries such as Bangladesh with increasingly saline groundwater and polluted surface water, but feasibility systems require careful assessment (Naus et al 2021). Naser et al (2021) found that people consuming MAR water had higher urinary sodium and higher blood pressure than those continuing to rely on surface water sources and concluded that MAR should not be promoted as a routine water supply option. Such risk substitutions have been identified before in Bangladesh in relation to arsenic (Howard, 2003), but the risks with microbiological contamination tend to substantially outweigh those associated with chemical contaminants (Howard et al 2006a).…”