One in five people aged over 40 in two coastal upazilas with high drinking-water salinity face a moderate-to-high risk of cardiovascular disease, according to preliminary findings of a new study.
The findings, presented yesterday at a policy and dissemination seminar in Dhaka, highlighted another health threat for climate-vulnerable communities.
The event titled “Drinking Water Salinity and Impact on Health: Bangladesh Evidence and Policy Recommendations” was organised by icddr,b in collaboration with Imperial College London.
Aliya Naheed, senior scientist at icddr,b, presented the findings from the ongoing Bangladesh programme of the NIHR Global Health Research Centre for Non-Communicable Diseases and Environmental Change. The study, which began in 2023, is expected to be completed next year.
“For millions of people living in coastal Bangladesh, the water they depend on every day is becoming a growing health concern,” Aliya said.
“Drinking-water salinity is no longer only an environmental challenge; increasing sodium exposure can contribute to high blood pressure and related cardiovascular and kidney diseases, while women may face additional risks during pregnancy,” she said.
The study assessed drinking-water sources in 172 villages under 71 community clinic catchment areas in Koyra upazila of Khulna, the intervention area, and Assasuni upazila in Satkhira, the usual-care comparison area.
Researchers surveyed 27,697 water sources, of which 6,703, or 24.2 percent, were used for drinking.
Salinity was detected in 55.3 percent of drinking-water sources in Koyra and 23.3 percent in Assasuni.
The researchers also assessed cardiovascular disease risk among 15,471 adults aged 40 and above in the two upazilas.
Overall, 21.6 percent were estimated to have a moderate-to-high 10-year cardiovascular disease risk, defined as at least 10 percent.
The risk was 19.7 percent in Koyra and 23.6 percent in Assasuni.
Aliya said there is an association between saline drinking water, particularly sodium exposure, and high blood pressure, a major risk factor for cardiovascular disease.
She said differences in other risk factors, including gender and tobacco use, might have contributed to the variation between the two upazilas.
A previous WHO survey estimated the national cardiovascular risk at 9.02 percent among adults aged 40–69. In comparison, the study found the risk was around 11 percent among people of the same age group in the two upazilas and 21.6 percent among those aged 40 and above.
As part of the research, the team has designed an integrated package of water and primary healthcare interventions to improve access to low-salinity drinking water.
These include rainwater harvesting, pond sand filters and tube wells, along with stronger monitoring.
The package also includes digital screening, referral and follow-up for hypertension, diabetes and chronic kidney disease through primary healthcare services.
Prof Paolo Vineis of Imperial College London said available evidence does not establish a clear health-based threshold for drinking-water salinity.
He stressed the need for national and international institutions to develop appropriate health-based guidelines while research continues into how sodium and other minerals in drinking water affect health.
Prof Adrian Butler of Imperial College London presented evidence on how tropical-cyclone storm surges can cause long-term salinisation of drinking-water ponds and shallow groundwater.
He emphasised the need to maintain and, where appropriate, raise polder embankments, along with rapid clean-up and restoration of water sources after storm surges.
Tahmeed Ahmed, executive director of icddr,b, said evidence linking climate change with health outcomes in Bangladesh remains limited, with even less research focusing on practical adaptation strategies and innovations.
Fahmida Khanom, acting secretary of the Ministry of Environment, Forest and Climate Change, said salinity is already a major health problem for coastal communities and climate change would intensify salinity intrusion.
Evidence such as this is important not only for national action but also for strengthening Bangladesh’s position in international climate negotiations and emphasising adaptation and mitigation strategies, she added.
Lutfor Rahman, director general of the Department of Environment, and Sheikh Momena Moni, additional secretary of the health ministry, among others, spoke at the programme. Prof Pravath Chandra Biswas, director general of the Directorate General of Health Services, chaired the event.
