Hypertensive disorders in salinity prone coastal areas: relevance to global climate change
File(s)
Author(s)
Scheelbeek, Pauline Franka Denise
Type
Thesis
Abstract
Introduction
High intake of sodium (as salt) is an important risk factor for high blood pressure. In climate change affected coastal areas, such as in Bangladesh, extremely high sodium concentrations are measured in drinking water sources. Drinking water (in addition to food) could therefore play an important role in the burden of raised blood pressure in these areas. We further investigated the relationship between drinking water salinity and blood pressure of coastal populations using different study designs.
Methods & Results
Previous studies of drinking water sodium and blood pressure yielded varied results – though all found randomised controlled trials showed a positive association. Evaluated sodium levels were usually much lower than those measured in Bangladesh and most studies were conducted in predominantly white, high-income populations.
Secondary analysis of data on pregnant women showed that drinkers of tube-well and pond water (sources high in sodium) had significant higher average blood pressure (4.85/2.30 and 3.62/1.72 mmHg respectively) than rainwater drinkers. Regression analysis with space and time parameters showed that sodium concentrations in these sources were inversely associated with distance to rivers and showed clear (increasing) trends over the course of the dry season.
A longitudinal study among 581 coastal participants showed that decreases in drinking water sodium concentrations were significantly associated with decreases in blood pressure of its users. For each 100 mg/l decrease in sodium, blood pressure dropped on average with 0.95/0.57 mm Hg; odds of hypertension decreased under the same reduction with 20% and 14% for systolic and diastolic hypertension respectively.
Conclusions
This study found supporting evidence for the hypothesis that drinking highly saline water causes high blood pressure and hypertension in adults and pregnant women in salinity affected coastal areas. These increases could be successfully reversed when users change to a saline lower alternative. In view of current climate change predictions, drinking water salinity problems are expected to rise and affect millions of coastal people worldwide; therefore further recognition of the problem and exploring the feasibility of drinking water alternatives should be prioritised and incorporated in future (health) planning in salinity-prone coastal areas.
High intake of sodium (as salt) is an important risk factor for high blood pressure. In climate change affected coastal areas, such as in Bangladesh, extremely high sodium concentrations are measured in drinking water sources. Drinking water (in addition to food) could therefore play an important role in the burden of raised blood pressure in these areas. We further investigated the relationship between drinking water salinity and blood pressure of coastal populations using different study designs.
Methods & Results
Previous studies of drinking water sodium and blood pressure yielded varied results – though all found randomised controlled trials showed a positive association. Evaluated sodium levels were usually much lower than those measured in Bangladesh and most studies were conducted in predominantly white, high-income populations.
Secondary analysis of data on pregnant women showed that drinkers of tube-well and pond water (sources high in sodium) had significant higher average blood pressure (4.85/2.30 and 3.62/1.72 mmHg respectively) than rainwater drinkers. Regression analysis with space and time parameters showed that sodium concentrations in these sources were inversely associated with distance to rivers and showed clear (increasing) trends over the course of the dry season.
A longitudinal study among 581 coastal participants showed that decreases in drinking water sodium concentrations were significantly associated with decreases in blood pressure of its users. For each 100 mg/l decrease in sodium, blood pressure dropped on average with 0.95/0.57 mm Hg; odds of hypertension decreased under the same reduction with 20% and 14% for systolic and diastolic hypertension respectively.
Conclusions
This study found supporting evidence for the hypothesis that drinking highly saline water causes high blood pressure and hypertension in adults and pregnant women in salinity affected coastal areas. These increases could be successfully reversed when users change to a saline lower alternative. In view of current climate change predictions, drinking water salinity problems are expected to rise and affect millions of coastal people worldwide; therefore further recognition of the problem and exploring the feasibility of drinking water alternatives should be prioritised and incorporated in future (health) planning in salinity-prone coastal areas.
Version
Open Access
Date Issued
2015-04
Date Awarded
2015-07
Copyright Statement
Attribution NoDerivatives 4.0 International Licence (CC BY-ND)
Advisor
Vineis, Paolo
Elliott, Paul
Blangiardo, Marta
Sponsor
MRC-PHE; Leverhulme Trust
Grant Number
Leverhulme Trust
Publisher Department
School of Public Health. Epidemiology and Biostatistics
Publisher Institution
Imperial College London
Qualification Level
Doctoral
Qualification Name
Doctor of Philosophy (PhD)