Tap water in US linked to potential cardiovascular risks
The water you drink may be raising your blood pressure and increasing your risk of hypertension, according to a new meta-analysis published in BMJ Global Health.[1]
“Global groundwater, which makes up nearly half of the world’s drinking water supply, is affected by varying mineral compositions due to infiltration from different sources, such as rain and surface water,” wrote senior author Rajiv Chowdhury, PhD, chair of the department of global health at Florida International University’s Robert Stempel College of Public Health and Social Work. “Climate change is expected to further alter these mineral compositions, such as in coastal areas where rising sea levels are speeding up salinity intrusion into groundwater and soil. This increased salinity (defined as the dissolved salt content of a body of water) is a potentially significant global health challenge because: (a) over 3 billion people worldwide currently live in coastal or near-coastal areas and (b) most of these coastal populations are located in low-income and middle-income countries, where people drink water from sources with high salinity levels.”
Chowdhury et al. reviewed data from more than 74,000 adults who participated in one of 27 different studies all over the world. While 11 studies were held in North America, another 10 were held in Asia and three were held in Europe. Australia and Africa were each home to one study included in the team's meta-analysis.
Overall, they found that higher salinity in a person’s drinking water was associated with higher systolic and diastolic blood pressure levels. The average systolic blood pressure was 3.2 mm Hg higher, for example, and the average diastolic blood pressure was nearly 2.8 mm Hg higher.
In addition, drinking water with higher salinity was linked to a 26% higher risk of developing hypertension. This trend was the most evident in coastal parts of the world, where people live right next to the water.
Chowdhury and his team did emphasize that this does not mean a person’s drinking water could suddenly be seen as unsafe; this is more about informing the public about a single cardiovascular risk factor than saying they can’t drink what flows out of their own taps.
“This is not about alarming people,” Chowdhury said in a statement from Florida International University. “It’s about recognizing an environmental factor that may be contributing to high blood pressure in some communities and making sure it’s part of the public health conversation. In the U.S., most people already consume more sodium than recommended, so additional sodium from saltier drinking sources may only add to overall intake.”
Another goal of this research is to potentially bring about policy changes.
“By linking drinking water salinity to blood pressure risk, this study provides useful context for future water management and public health decisions and provides even more focus on the importance of protecting our groundwater resources,” Todd Crowl, director of the Institute of Environment at Floridia International University, said in the same statement. “For South Florida, this puts even more importance on Everglades restoration which ultimately will protect our freshwater from further saltwater intrusion.”
The research team hopes to learn how drinking water salinity may impact a person’s risk of heart attack, stroke or other adverse cardiovascular events. For now, however, they said they haven’t seen enough data yet to make a determination of any kind.
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Michael has more than 19 years of experience as a professional writer and editor. He has written at length about cardiology, radiology, artificial intelligence and other key healthcare topics.