BARCELONA, Spain — We’ve all dealt with the occasional noisy party next door or been woken up rudely by a car alarm, but these are just small annoyances with no real health consequences right? Well, according to a new international study conducted in Barcelona, Spain, all that noise may actually cause a more serious stroke at a later time.
Researchers from both Spain and the United States investigated the influence of noise levels, air pollution (PM), and exposure to green spaces on close to 3,000 ischemic stroke patients being treated at Barcelona’s Hospital del Mar between 2005-2014. They found that individuals living in especially noisy areas are at a 30% higher risk of suffering a stroke with increased severity and consequences. Conversely, people who live close to green areas and nature were found to have a 25% lower risk of suffering an especially serious stroke.
To come to their conclusions, the study’s authors constructed models analyzing air pollutant levels, a noise map of Barcelona, and satellite images identifying nearby vegetation and green spaces. Each patient’s socioeconomic status was also considered.
This is the first set of research, ever, to investigate how these three factors influence stroke severity.
“We have observed a gradient: the more green spaces, the less serious the stroke. And the more noise, the more serious it is. This suggests that factors other than those traditionally associated with stroke may play an independent role in the condition,” explains first study author Dr. Rosa María Vivanco in a release.
Interestingly, no link was observed between air pollution and stroke severity, but researchers say they were limited in this aspect due to the fact that the majority of study subjects had been exposed to the same air (Barcelona) for the majority of their lives. With this in mind, it is hard to draw any definitive conclusions.
“Previous studies have demonstrated that living in places with high levels of air pollution or noise, or with fewer green areas, exposes the population to a higher risk of suffering an ischemic stroke. This work broadens our knowledge in this field, showing that the place where we live affects not only the risk of suffering a stroke, but also its severity if it occurs,” explains Dr. Gregory A. Wellenius, a professor at Brown University and the study’s final author.
Of course, a variety of elements are at play when determining the severity of a stroke. Still, the research team say their findings should be significant enough to be taken into account by doctors and other health professionals.
“The severity of a stroke depends on various factors, including the extent of the brain injury, the specific area of brain affected, the subtype of stroke, the existence of associated risk factors (diabetes, atrial fibrillation, atherosclerotic load), and so on. The fact that we have demonstrated, in addition to all these factors, that environmental aspects like green spaces and urban noise levels affect the severity of a stroke and therefore our health, shows that this information must be taken into account by political and health planners,” comments co-author Dr. Jaume Roquer.
The researchers did not determine an exact sound level that leads to increased risk of serious stroke, as they only compared patients living in generally noisier areas with patients living in quieter neighborhoods. However, they theorize it is likely well above the World Health Organization’s recommended limits of 53 decibels during the day and 25 decibels in the evening.
The study is published in the scientific journal Environmental Research.