People living near a major roadway have an increased risk of high blood pressure; a new study has observed.
Researchers from Brown University, have concluded that hypertension risk rose with proximity to the roadways. The risk of hypertension was 22 % higher among women who lived within 100 meters of a highway or major arterial road than women who lived 1,000 meters away.
In epidemiological terms, a 58-year-old woman who lived close to a major road had blood pressure risk equal to that of a 60-year-old woman who lived away from a high way. The elevated risk reported in the study statistically explains many cardiovascular risk factors like age, demographics, health, and lifestyle and fast food availability.
Hypertension is a basic cause of many cardiovascular diseases. For that reason, the increased likelihood of hypertension reported in the new study may help explain prior findings of proximity to major roadways and cardiovascular diseases like stroke.
“This study does tip the scale in favor of being concerned about the urban environment and how we develop our cities and our transportation systems,” explains Gregory Wellenius, assistant professor of epidemiology at the Brown University School of Public Health.
“There are a lot of new developments going up right near highways. One has to start thinking about what are the associated health effects with that.”
The study gathered data from a wide variety of personal health and demographic measures, including where participating women lived, their blood pressure and other key attributes.
Wellenius and his team used software to measure the distance from each woman’s home to a major roadway. They also consulted a database to determine each neighborhood’s abundance of supermarkets and fast-food restaurants to determine who lived in a so-called “food desert” where unhealthy food options were relatively many and healthier ones relatively few.
They then looked at the association between the prevalence of high blood pressure and distance from the highway.
In three levels of analysis, the researchers controlled for more and more possible confounding factors. In all, they controlled for age, ethnicity, smoking status, education, household income, cholesterol, body-mass index, diabetes history, physical activity level, and local food quality.
After all that, they found the odds of hypertension were 1.22 to 1 for those living closest, 1.13 to 1 for those between 100 and 200 meters, and 1.05 to 1 for those between 200 and 1000 meters from a major roadway. These odds are indexed such that 1 represents the prevalence risk of those living more than 1,000 meters from a major roadway.
Wellenius acknowledged that because the study only measured who had hypertension and where they lived at one moment in time, it does not necessarily show a causal link.
The study, however, specifically does not shed light on how closeness to the road that could cause hypertension. It could be airborne pollutants or noise or both. Other studies in the past have shown specific physiological effects of pollution and noise relevant to cardiovascular disease.
Hypertension, even when treated, still carries an elevated risk of cardiovascular disease, Wellenius cautions. According to him, the best policy, is prevention.
“The public health message is that we need to take into consideration the health of the population when planning neighborhoods, when planning transportation systems, and when deciding where new highways are going to go, and how we might be able to mitigate traffic or its effects,” Wellenius said.
In addition to Kirwa and Wellenius, other authors are Melissa Eliot, Yi Wang, and Dr. Charles Eaton of Brown; Marc Adams of Arizona State University; and Cindy Morgan, Jacqueline Kerr, Gregory Norman, and Dr. Matthew Allison of the University of California–San Diego.
The study has been cited in the Journal of the American Heart Association.
