An analysis of census data found a striking correlation between regions where a majority of commuters drive to work and regions where obesity and diabetes rates are highest.
"It is not our intent to claim a direct causal link between transportation modes and obesity rates," wrote the authors of the analysis from Planetizen. "[But] it is hard to deny the existence of some geographic patterns."
Their analysis was a reexamination of a previously released 2011 article, which explored the relationship between "sedentary travel" — driving as opposed to walking or biking — and health outcomes. In this newer analysis, the authors mapped out data at the county level for incidence rates of obesity, diabetes, and sedentary transit.
While the maps were not perfectly identical, there was an undeniable correlation, with the so-called "diabetes belt" stretching from Appalachia into the Deep South lining up strongly with the counties reporting the highest rates of sedentary commuters.
This isn't the first time that traffic and health outcomes have been linked. Several studies have examined the negative effects of traffic-related air pollution, which has been identified as a top contributor to early death worldwide. Rising trends in childhood obesity have also specifically been linked to increases in air pollution.
Additionally, sitting in traffic causes spikes in blood pressure that can last as long as 24 hours. Researchers have even found a link between long-term traffic noise exposure and diabetes.
As the authors pointed out, however, there are numerous other factors that influence the diabetes-commuter pattern. "The next avenue of study would be to determine how much of this pattern is actually attributable to transportation mode, versus other factors," they wrote. These other factors include education, income, food choices, sedentary hobbies, stress, and unemployment.
As complex as these issues are, there are reasons to be hopeful that the diabetes and obesity numbers could be reduced. One recent study found that the adoption of electric vehicles was linked with less air pollution and improved health. And those people who bike and walk continue to reap the benefits, from a reduced risk of diabetes, cardiovascular disease, and other conditions to improved mental health.
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