ArticlePDF Available

Salinity in Drinking Water and the Risk of (Pre)Eclampsia and Gestational Hypertension in Coastal Bangladesh: A Case-Control Study

DOI: 10.1371/journal.pone.0108715
Authors:
Aneire Khan at Imperial College London
Aneire Khan
Pauline Scheelbeek at London School of Hygiene and Tropical Medicine
Pauline Scheelbeek
Asma Begum Shilpi
Asma Begum Shilpi
Asma Begum Shilpi
  • This person is not on ResearchGate, or hasn't claimed this research yet.
Queenie Chan at Imperial College London
Queenie Chan
Show all 8 authorsHide
Download full-text PDFDownload full-text PDF
Read full-text
Download citation

Abstract and Figures

Background Hypertensive disorders in pregnancy are among the leading causes of maternal and perinatal death in low-income countries, but the aetiology remains unclear. We investigated the relationship between salinity in drinking water and the risk of (pre)eclampsia and gestational hypertension in a coastal community. Methods A population-based case-control study was conducted in Dacope, Bangladesh among 202 pregnant women with (pre)eclampsia or gestational hypertension, enrolled from the community served by the Upazilla Health Complex, Dacope and 1,006 matched controls from the same area. Epidemiological and clinical data were obtained from all participants. Urinary sodium and sodium levels in drinking water were measured. Logistic regression was used to calculate odds ratios, and 95% confidence intervals. Findings Drinking water sources had exceptionally high sodium levels (mean 516.6 mg/L, S.D 524.2). Women consuming tube-well (groundwater) were at a higher disease risk than rainwater users (p<0.001). Adjusted risks for (pre)eclampsia and gestational hypertension considered together increased in a dose-response manner for increasing sodium concentrations (300.01–600 mg/L, 600.1–900 mg/L, >900.01 mg/L, compared to <300 mg/L) in drinking water (ORs 3.30 [95% CI 2.00–5.51], 4.40 [2.70–7.25] and 5.48 [3.30–9.11] (p-trend<0.001). Significant associations were seen for both (pre)eclampsia and gestational hypertension separately. Interpretation Salinity in drinking water is associated with increased risk of (pre)eclampsia and gestational hypertension in this population. Given that coastal populations in countries such as Bangladesh are confronted with high salinity exposure, which is predicted to further increase as a result of sea level rise and other environmental influences, it is imperative to develop and evaluate affordable approaches to providing water with low salt content.
Figures - uploaded by Andy Haines
Author content
All figure content in this area was uploaded by Andy Haines
Content may be subject to copyright.
pone.01087
15.pdf
Content uploaded by Andy Haines
Author content
All content in this area was uploaded by Andy Haines on Nov 20, 2014
Content may be subject to copyright.
Salinity in Drinking Water and the Risk of (Pre)Eclampsia and Gestational Hypertension in Coastal Bangladesh: A Case-Control Stu
dy.pdf
Available via license: CC BY 4.0
Content may be subject to copyright.
A preview of the PDF is not available
... Increased salt intake through saline water is also associated with pregnancy complications (e.g., miscarriage), dermatitis, and reproductive health issues. A recent study showed that miscarriage rates are high in saline-prone areas [60,71], and local public health officials noted that preeclampsia, eclampsia, and hypertension are present among many pregnant women in the area [72,73]. Women may also experience changes in their menstrual cycle, and there is an increased risk of pre-term birth [72,74,75]. ...
... A recent study showed that miscarriage rates are high in saline-prone areas [60,71], and local public health officials noted that preeclampsia, eclampsia, and hypertension are present among many pregnant women in the area [72,73]. Women may also experience changes in their menstrual cycle, and there is an increased risk of pre-term birth [72,74,75]. One key informant revealed that due to the lack of fresh water, women bathe in brackish or saline water, which also creates hygiene issues connected with reproductive organs related to the inability to remove the saline residues, such as itching. ...
View
... Increased salt intake through saline water is also associated with pregnancy complications (e.g., miscarriage), dermatitis, and reproductive health issues. A recent study showed that miscarriage rates are high in saline-prone areas [60,71], and local public health officials noted that preeclampsia, eclampsia, and hypertension are present among many pregnant women in the area [72,73]. Women may also experience changes in their menstrual cycle, and there is an increased risk of pre-term birth [72,74,75]. ...
... A recent study showed that miscarriage rates are high in saline-prone areas [60,71], and local public health officials noted that preeclampsia, eclampsia, and hypertension are present among many pregnant women in the area [72,73]. Women may also experience changes in their menstrual cycle, and there is an increased risk of pre-term birth [72,74,75]. One key informant revealed that due to the lack of fresh water, women bathe in brackish or saline water, which also creates hygiene issues connected with reproductive organs related to the inability to remove the saline residues, such as itching. ...
Collective Intelligence for Addressing Community Planetary Health Resulting from Salinity Prompted by Sea-Level Rise
Article
  • Jan 2023
Sea-level rise-induced salinity encroachment is causing various community-level planetary health impacts in coastal areas worldwide. The coastal area of Bangladesh is no exception. Driven by sea-level rise, coastal Bangladesh's salinity is amplified by other factors such as shrimp cultivation, reduction of transboundary river flow in the dry season, mismanagement of the embankment, and frequent cyclone-related storm surge. Due to the salinity encroachment in this region, water and soil salinity is increasing, resulting in multiple planetary health impacts. Based on twenty years of field observation and a literature review, these planetary health impacts can be categorized as (i) primary health consequences (communicable and non-communicable diseases; scarcity of potable water), (ii) secondary health consequences (food and nutrition security; migration and related health impacts) and (iii) tertiary health consequences (adaptation-related emerging diseases; disaster-related health vulnerability). By exploring these multidimensional health impacts and associated factors of salinity, a collective intelligence-based framework is described to address the planetary health impacts in this paper. Collective intelligence can be a valuable technique to engage multiple stakeholders to share data, gather data, and model the health impacts of salinity. Collective intelligence can also help indicate appropriate interventions to address the planetary health impacts of increasing salinity.
View
... The impact on the wellbeing of the population may be aggravated by the salinisation of groundwater and surface water resources, with an association between drinking water salinity and prevalent hypertension identified in the region (Khan et al. 2014;Scheelbeek et al. 2017). Ecosystem services (forest products, aquatic resources and natural hazard protection) are also at risk (Dearing and Hossain 2018;Newton et al. 2020), weakening resilience of the coastline to sealevel rise and cyclone-induced storm surge. ...
... Surface water and aquifer resources are also threatened by increasing salinity (Hoque et al. 2016), with storm surge inundation not only driving the salinisation of shallow groundwater (Islam et al. 2019) but also resulting in the contamination of drinking water ponds (Hoque et al. 2016). Cohort studies have identified an association between increased Na concentration in drinking water and increased rates of hypertensive disorders such as (pre)eclampsia (Khan et al. , 2014, increased infant mortality (Dasgupta et al. 2016) and other cardio-metabolic health issues (Scheelbeek et al 2017). In coastal Bangladesh and other Asian deltas, drinking water sources with high saline content are reported Published in partnership with CECCR at King Abdulaziz University to be contributing to an increased intake of sodium (Hoque and Butler 2015). ...
Coastal Salinity and Water Management Practices in the Bengal Delta: A Critical Analysis to Inform Salinisation Risk Management Strategies in Asian Deltas
Article
Full-text available
  • Dec 2022
Salinisation within delta environments is a dynamic process governed by the interaction between coastal, fluvial and geomorphological systems. Increasingly, these have been modified through human activity and management practices, which lead to unintended problems associated with waterlogging and salt accumulation in soils and water resources. As a result of these issues, over 100 million people in the Ganges–Brahmaputra and other Asian deltas are negatively affected by a lack of freshwater availability and decreased crop yields. Rising sea levels, climate change, and population increase are all likely to exacerbate these problems. Using an iterative approach of literature review, we analyse the evolution of water management practices and policy and how these have influenced salinity within the delta, with a conceptual framework of understanding developed to guide risk management strategies. We find that management of coastal flooding and salinisation is hampered by socio-economic conditions and the dynamic hydro-morphology of the delta, which has increasingly been altered through diversion and abstraction of upstream flow. Whilst engineering solutions protect large areas from inundation, interruption of natural flood-dynamics also increases the potential impact from storm-surge and fluvio-tidal flooding. To limit salinity, policies based on salinisation science, as well as the implementation of adequately financed, multi-layered, integrated risk management plans at the local, regional, and river basin levels, are required. The promotion of stakeholder engagement should be encouraged to ensure local co-operation and effective implementation of policies. The mitigation of the multiple and cascading hazards associated with salinisation caused by anthropogenic activity, climate change and socio-economic development is crucial for the populations of delta regions across Asia.
View
... For instance, floods or tidal surges can outpour deep wells, ponds, streams, and other waterways, contaminating the natural freshwater sources in the process [102,1]. As a result, water insecurity has become imminent more or less all-around Bangladesh, albeit the coastal inhabitants are conspicuously victimized due to salinity intrusion owing to the crisis of water resources for drinking and household usage [2,53,89]. Moreover, climate change has indeed been attributed to several short and long-term health risks, including a rise in communicable diseases (water-borne, vector-borne, and food-borne), non-communicable diseases (such as cardiovascular and cerebrovascular disease; high blood pressure; and mental illness), and innutrition [66,25]. ...
The impact of climate change on water resources and associated health risks in Bangladesh: A review
Article
  • Mar 2023
Bangladesh is increasingly experiencing different challenges from scarce drinking water sources and health risks, explicitly or implicitly attributed to climate change. This systematic bibliographic review manually screened 47 articles under four categories, including Water and health; Climate and water; Climate and health; and Climate, water, and health, from 2010 to 2022. This research is critical for ensuring the availability of safe drinkable water and public health adaptation to climate change in Bangladesh. The findings revealed that cholera, infant diarrhea, pneumonia, dengue, and malaria are prevalent in the vulnerable groups. The present number and distribution of regional healthcare centers demonstrates potable water procedures and medical centers are insufficient relative to demands. Overall, this study revealed several techniques that help guarantee safe potable water, including holding rainwater, pond sand filters, and drinkable water supply. A knowledge-based approach was used to propound an adaptation framework for tackling the impact of changing climate, especially on safe water availability and public health, and also identified six research gaps. This research serves as a roadmap for future scholars, academicians, practitioners, and policymakers and indicates the need for more progress in the database on national climate change research.
View
... The study further added that women and those 35 years and older are the at-risk populations for blood pressure anomalies, notably from deep tube wells which are generally perceived as a safe water source from arsenic and fecal coliform contamination and thus pose a threat to future water security. Exposure to saline drinking water has also been positively linked to pre-eclampsia and gestational hypertension among coastal pregnant women [120]. Women from the salinity-affected coastal areas have reported suffering from skin irritation and bleeding in their private parts due to washing clothes in saline water, which ultimately resulted in increased domestic violence and divorce and abandonment [80]. ...
Public Health Impact and Health System Preparedness within a Changing Climate in Bangladesh: A Scoping Review
Article
Full-text available
  • Jan 2023
Bangladesh, one of the most disaster-prone countries in the world is also severely exposed to climate change (CC) impacts with a multitude of health complexities. Health adaptation to CC is thus a serious issue in Bangladesh, but not explored properly from a health system and policy environment perspective. In order to address this gap and provide a holistic picture of the overall scenario, this scoping review explores CC impacts on the population health in Bangladesh and discusses the policy environment and health system preparedness against such climatic challenges. A total of 28 articles were reviewed following Arksey and O’Malley’s scoping review framework. A “5-point scale” was devised to assess CC integration in the health sector Operational Plans (OPs). Though the country made significant progress in different health indicators, poverty and income inequality have kept marginal communities out of many health provisions. There are four major stakeholders in the health system. The government sector is handicapped by poor governance, bureaucratic processes, and staff shortages; and primarily focuses on the public sector only. National Health Policy (NHP) governs the health system through 29 sectoral OPs, that put CC as a major cross-cutting issue. About 25% of the OPs have fully integrated CC and other OPs have significant CC co-benefits. In Bangladesh CC was linked to increased morbidity and mortality, diarrhea, cholera, skin problems, respiratory infections, malaria, dengue, kala azar, pre-eclampsia, and hypertension. Significant research gaps exist on child health, migrant health, and mental health. Integration of research evidence into policy, planning and program design is largely absent. However, prioritizing health for the National Adaptation Plan is an essential step towards establishing a climate-resilient health system.
View
... When faced with trying to understand the complexity of what happens when a mixture of salt ions interacts with other anthropogenically derived substances in aquatic ecosystems, experts refer to the result as a "freshwater salinization syndrome" (FSS; Kaushal et al. 2018). Like any syndrome, the combination of complex factors (chemical, biological, geological, environmental, and social) associated with freshwater salinization can result in extreme consequences like unsafe drinking water (Ehmar Khan et al. 2014;Kaushal 2016); mobilized contaminants (Herbert et al. 2015;Kaushal et al. 2022); changes in the toxicity and bioaccumulation of co-occurring pollutants such as pesticides (Saranjampour et al. 2017;Hutton et al. 2021;Xing et al. 2022); and a loss of freshwater biodiversity (James et al. 2003;Castillo et al. 2018;Hintz and Relyea 2019;Hébert et al. 2022). FSS is expected to progress in five distinct stages as outlined here (this SI) for the first time (Kaushal et al. 2022). ...
View
Evaluation of the degree of water salinity in KUET concerning supplementary adjoining upazilas of the Khulna region and also to discern the low-cost salinity alleviation method in KUET
Conference Paper
Full-text available
  • Dec 2022
In coastal regions, salinity complications are an enormous labyrinth for groundwater. In KUET, salinity mitigation processes are a prerequisite as the Kuet area is not only comprised of academic buildings but also contains residential halls for several students. A survey has been performed among KUET students to assess the negatory outcome of salinity upon skin and hair. Moreover, around 90.8% of people suffer from severe hair loss, and for drinking, 61.8% of people use mineral water. The principal aim of this paper is to exhibit the comparison of water quality parameters between KUET and its other neighboring areas and criteria for evaluating water quality, mainly including Electrical Conductivity (EC), pH, Total Dissolved Solid (TDS), Cl-of water in the KUET region and other neighboring Upazilas of Khulna. Another aim is to indicate and assess the high, medium, and low salinity level areas in KUET. For the assessment of required datasets, we have used the areas of Doulotpur, Fultola, Paikgacha, Rupsha, and the KUET campus. Almost seven samples have been collected from selected areas, and the conducted tests are pH, EC (µs/cm), Cl (ppm), and TDS (ppm). According to the SRDI report and lab test report, Paikgacha and Rupsha have more EC than KUET, which is more than 150. The pH of this sample is around 7.3. Though the highest value of TDS is found to be 1100 ppm, most of the sample exhibits that the values remain in the optimum range (300ppm-600ppm). The hardness of the water in the KUET is around 650, which creates the water hard. These datasets containing samples obtained from different places make a clear map of the high, medium, and low salinity regions of the KUET campus compared with neighboring Upazilas. The scarcity of water is intensifying day by day with the geometric heightening of the population in the whole world. Although Bangladesh encounters rainfall all over the year on an average of at least 2425 mm all over the country [1], the country has a massive water supply deficiency. It is an affair of massive irony that potable water mainly depends upon groundwater sources, and we all know these resources are limited and non-renewable. Although it is free from pathogens, nevertheless groundwater contains varied complications. It can be seen when a comparison is carried out about the fresh, potable, and palatable water supply among coastal areas and other parts of the country, as a sufficient amount of fresh water is required for drinking and bathing. Climate change has raised the sea level, which leads to the contamination of salinity via the intrusion of saline water into the groundwater, which not only contaminates the drinking water but also contaminates the soil, which makes the ground uncultivable. There is around 30% or more cultivable land in the country in the coastal region. The coastal region of Bangladesh is only 1m to 3m above the mean sea level [2]. Salinity is not only a problem for drinking purposes but also a problem for other domestic, household, and irrigation purposes. The crops which are intolerant to saline water cannot be well-generated in this region. It affects the livelihood operation of people, as salinity reduces soil fertility and creates a shortage of fresh drinking water. Due to the hydrogeological location of Bangladesh, it is vulnerable to the hazard of storm surges and tidal flood that causes more salinity.
View
Drinking Water From Private Wells and Risks to Children
Article
  • Jan 2023
Drinking water for approximately 23 million US households is obtained from private wells. These wells can become contaminated by pollutant chemicals or pathogenic organisms, leading to significant illness. Although the US Environmental Protection Agency and all states offer guidance for construction, maintenance, and testing of private wells, most states only regulate the construction of new private water wells. With a few exceptions, there is little regulation after construction. Well owners are responsible for their own wells. Children may also drink well water at child care or when traveling. Illness resulting from children’s ingestion of contaminated water can be severe. This report reviews relevant aspects of groundwater and wells; describes the common chemical and microbiologic contaminants; gives an algorithm with recommendations for inspection, testing, and remediation for wells providing drinking water for children; and provides references and Internet resources for more information.
View
The impact of water quality of GDP growth: Evidence from around the world
Article
  • Dec 2022
Declining water quality can impact the economy in various ways. Impacts can be found in the health sector, where labor productivity can be affected, in agriculture, where the quality and quantity of food produced can be reduced, and in tourism, real estate, aquaculture/fisheries and other sectors which rely on environmental quality and ecosystem services. Despite these well-known impacts, finding economy-wide effects of water quality on economic activity can be elusive. In this paper we attempt to fill this gap by using new data on economic activity and water quality for 17 countries from 1990 to 2014 and a panel fixed-effect model that accounts for endogeneity between pollution and economic growth through the direction of streamflow. We find that when rivers become very heavily polluted, regions downstream see reductions in economic growth, losing between 1.4 and 2.5 percent of economic growth, depending on development level and the level of pollution. These losses imply that in many places, the costs of environmental degradation are severely under-estimated and pollution is well above efficient levels.
View
View
Estimating 24-Hour Urinary Sodium Excretion From Casual Urinary Sodium Concentrations in Western Populations: The INTERSALT Study
Article
Full-text available
  • May 2013
High intakes of dietary sodium are associated with elevated blood pressure levels and an increased risk of cardiovascular disease. National and international guidelines recommend reduced sodium intake in the general population, which necessitates population-wide surveillance. We assessed the utility of casual (spot) urine specimens in estimating 24-hour urinary sodium excretion as a marker of sodium intake in the International Cooperative Study on Salt, Other Factors, and Blood Pressure. There were 5,693 participants recruited in 1984-1987 at the ages of 20-59 years from 29 North American and European samples. Participants were randomly assigned to test or validation data sets. Equations derived from casual urinary sodium concentration and other variables in the test data were applied to the validation data set. Correlations between observed and estimated 24-hour sodium excretion were 0.50 for individual men and 0.51 for individual women; the values were 0.79 and 0.71, respectively, for population samples. Bias in mean values (observed minus estimated) was small; for men and women, the values were -1.6 mmol per 24 hours and 2.3 mmol per 24 hours, respectively, at the individual level and -1.8 mmol per 24 hours and 2.2 mmol per 24 hours, respectively, at the population level. Proportions of individuals with urinary 24-hour sodium excretion above the recommended levels were slightly overestimated by the models. Casual urine specimens may be a useful, low-burden, low-cost alternative to 24-hour urine collections for estimation of population sodium intakes; ongoing calibration with study-specific 24-hour urinary collections is recommended to increase validity. © 2013 © The Author 2013. Published by Oxford University Press on behalf of the Johns Hopkins Bloomberg School of Public Health. All rights reserved. For permissions, please e-mail: [email protected] /* */
View
Intersalt revisited: further analyses of 24 hour sodium excretion and blood pressure within and across populations. Intersalt Cooperative Research Group
Article
Full-text available
  • May 1996
Objectives: To assess further the relation in Intersalt of 24 hour urinary sodium to blood pressure of individuals and populations, and the difference in blood pressure from young adulthood into middle age. Design: Standardised cross sectional study within and across populations. Setting: 52 population samples in 32 countries. Subjects: 10,074 men and women aged 20-59. Main outcome measures: Association of sodium and blood pressure from within population and cross population multiple linear regression analyses with multivariate correction for regression dilution bias. Relation of sample median daily urinary sodium excretion to difference in blood pressure with age. Results: In within population analyses (n = 10,074), individual 24 hour urinary sodium excretion higher by 100 mmol (for example, 170 v 70 mmol) was associated with systolic/diastolic blood pressure higher on average by 3/0 to 6/3 mm Hg (with and without body mass in analyses). Associations were larger at ages 40-59. In cross population analyses (n = 52), sample median 24 hour sodium excretion higher by 100 mmol was associated with median systolic/diastolic pressure higher on average by 5-7/2-4 mm Hg, and estimated mean difference in systolic/diastolic pressure at age 55 compared with age 25 greater by 10-11/6 mm Hg. Conclusions: The strong, positive association of urinary sodium with systolic pressure of individuals concurs with Intersalt cross population findings and results of other studies. Higher urinary sodium is also associated with substantially greater differences in blood pressure in middle age compared with young adulthood. These results support recommendations for reduction of high salt intake in populations for prevention and control of adverse blood pressure levels.
View
Nutrition of Children and Women in Bangladesh: Trends and Directions for the Future
Article
Full-text available
  • Mar 2012
Although child and maternal malnutrition has been reduced in Bangladesh, the prevalence of underweight (weight-for-age z-score <-2) among children aged less than five years is still high (41%). Nearly one-third of women are undernourished with body mass index of <18.5 kg/m2. The prevalence of anaemia among young infants, adolescent girls, and pregnant women is still at unacceptable levels. Despite the successes in specific programmes, such as the Expanded Programme on Immunization and vitamin A supplementation, programmes for nutrition interventions are yet to be implemented at scale for reaching the entire population. Given the low annual rate of reduction in child undernutrition of 1.27 percentage points per year, it is unlikely that Bangladesh would be able to achieve the United Nations' Millennium Development Goal to address undernutrition. This warrants that the policy-makers and programme managers think urgently about the ways to accelerate the progress. The Government, development partners, non-government organizations, and the academia have to work in concert to improve the coverage of basic and effective nutrition interventions, including exclusive breastfeeding, appropriate complementary feeding, supplementation of micronutrients to children, adolescent girls, pregnant and lactating women, management of severe acute malnutrition and deworming, and hygiene interventions, coupled with those that address more structural causes and indirectly improve nutrition. The entire health system needs to be revitalized to overcome the constraints that exist at the levels of policy, governance, and service-delivery, and also for the creation of demand for the services at the household level. In addition, management of nutrition in the aftermath of natural disasters and stabilization of prices of foods should also be prioritized.
View
View
Chronic hypertension in pregnancy Reply
Article
Chronic hypertension in pregnancy is associated with increased rates of adverse maternal and fetal outcomes both acute and long term. These adverse outcomes are particularly seen in women with uncontrolled severe hypertension, in those with target organ damage, and in those who are noncompliant with prenatal visits. In addition, adverse outcomes are substantially increased in women who develop superimposed preeclampsia or abruptio placentae. Women with chronic hypertension should be evaluated either before conception or at time of first prenatal visit. Depending on this evaluation, they can be divided into categories of either "high risk" or "low risk" chronic hypertension. High-risk women should receive aggressive antihypertensive therapy and frequent evaluations of maternal and fetal well-being, and doctors should recommend lifestyle changes. In addition, these women are at increased risk for postpartum complications such as pulmonary edema, renal failure, and hypertensive encephalopathy for which they should receive aggressive control of blood pressure as well as close monitoring. In women with low-risk (essential uncomplicated) chronic hypertension, there is uncertainty regarding the benefits or risks of antihypertensive therapy. In my experience, the majority of these women will have good pregnancy outcomes without the use of antihypertensive medications. Antihypertensive agents are recommended and are widely used in these women despite absent evidence of either benefits or harm from this therapy. These recommendations are based on dogma and consensus rather than on scientific evidence. There is an urgent need to conduct randomized trials in women with mild chronic hypertension in pregnancy.
View
INTERSALT: an international study of electrolyte excretion and blood pressure. Results for 24h urinary sodium and potassium excretion. INTERSALT Cooperative Research Group. BMJ. 1988;297:319–328
Article
The Intersalt Cooperative Research Group, together with Laaser U Intersalt: An International Study of electrolyte excretion and blood pressure. Results for 24 hour urinary sodium and potassium excretion.
View
View
Effects of Exposure to Salty Drinking Water in an Arizona CommunityCardiovascular Mortality, Hypertension Prevalence, and Relationships Between Blood Pressure and Sodium Intake
Article
  • Feb 1986
A high level of sodium (440 mg/L) in the water supply of Gila Bend, Ariz, caused concern because of apparently elevated rates of hypertension in Gila Bend Papago Indians. We surveyed 342 Gila Bend Papago Indians and 375 non-Indians from July to September 1983. Participants 25 years of age and older were interviewed for health risk factors, water consumption, and dietary sodium and calcium intake and had height, weight, blood pressure, and urinary sodium and potassium levels measured. No consistent associations were found between any of the sodium values and systolic or diastolic blood pressure. Mean blood pressures for the Gila Bend whites were lower in most age groups than in comparison US white populations. The prevalence rates of hypertension in Gila Bend were not significantly higher than national rates. (JAMA 1986;255:622-626)
View
Impacts of climate change and sea-level rise on cyclonic storm surge floods in Bangladesh
Article
This paper describes the impacts of sea surface temperature (SST) rise and sea-level rise (SLR) on cyclonic storm surge flooding in western Bangladesh. A calibrated numerical hydrodynamic model was used to simulate surge wave propagation through the rivers and overland flooding. The model was calibrated with base condition (present climate), and then eight flooding scenarios of plausible future conditions were assessed by considering increased surge heights. Flooded area, flooding depth and surge intrusion length were computed by superimposing the predicted maximum water level information on a digital elevation model (DEM). This analysis showed that for a storm surge under 2 °C SST rise and 0.3 m SLR, flood risk area would be 15.3% greater than the present risk area and depth of flooding would increase by as much as 22.7% within 20 km from the coastline. Within the risk area, the study identified 5690 km2 land (22% of exposed coast) as a high-risk zone (HRZ) where flooding of depth 1 m or more might occur, and people should move to nearby cyclone shelters during extreme cyclonic events. Predicted area of HRZ is 1.26 times the currently demarcated HRZ. It was estimated that 320 additional shelters are required to accommodate people in the newly identified HRZ. This information would be of value to policy and decision makers for future shelter planning and designing shelter heights.
View
The Influence of Elevated Levels of Sodium in Drinking Water on Elementary and High School Students in Massachusetts
Article
Continuing epidemiologic studies at the University of Massachusetts have examined the hypothesis that elevated levels of sodium (Na) in drinking water contribute to elevations of blood pressure (BP). Comparing tenth graders from a town with 107 mg Na/L in the drinking water to those from a town with 8 mg, Na/L, revealed statistically significant and medically important higher BP distributions among the high Na town students relative to their low Na town peers for both systolic and diastolic BP in both boys and girls. The differences were upheld when potentially confounding factors, including dietary Na intake and other water factors occurring differentially in the two water supplies, were controlled in the analysis. A replication study among third graders in the same communities showed similar results.Most recently, an experimental bottled water study assessed the effect on bloodpressure of lowering Na concentration in the water of some of the high sodium community fourth graders. For three months trios of children matched by sex, school, and baseline BP each used different water for all cooking and drinking purposes, with BP monitored bi-weekly. Pupils were randomly allocated to the three water conditions: 1) high sodium water bottled from their own community distribution system, 2) low sodium water bottled from the distribution system of the comparison community with sodium added to the level of the high sodium community water and 3) low sodium water bottled from the distribution system of the low sodium community but with no sodium added.Preliminary results indicate the BP levels of the girls on the low sodium waterexhibited marked decreases in BP over the test period when compared to the other two groups.
View