Researchers at the Yale School of Public Health (SPH) may have opened up a new area in obesity research — the dentist’s office.

Their study, based on data compiled from national sources by the Robert Wood Johnson Foundation, established a correlation between the concentration of dentists and adult obesity rates in U.S. counties. For every additional dentist per 10,000 people in a county, the researchers noted a 1 percent drop in adult obesity rates. The findings suggest that dentists can play a key role in obesity prevention, said Jessica Holzer, study lead author and Hofstra University professor who conducted the research while a postdoctoral fellow at the SPH.

“The simple fact that there was this relationship was striking,” Holzer said. “There could potentially be a role that dentists could play in targeting or limiting obesity.”

Holzer, along with SPH co-authors Maureen Canavan and Elizabeth Bradley, initiated the study after looking at measures of county-level obesity rates and other factors related to health, which were made publicly available as part of the Robert Wood Johnson County Health Rankings and Roadmaps program. They chose dentist prevalence as their variable of interest because it had never before been studied in conjunction with obesity rates.

The researchers analyzed the effects of dentists while controlling for factors that previously correlated with obesity, including sociodemographic factors like education and income levels, as well as measures of the built environment, such as the number of recreational facilities and fast-food restaurants in a county. They also controlled for the observation that geographically proximate counties have similar obesity rates, as well as do counties within the same state.

Even when controlling for these factors, the researchers discovered that greater numbers of dentist offices correlated with lower rates of obesity. The effect was even more pronounced in counties with more primary care physicians, where each additional physician per 10,000 citizens resulted in a 1.7 percent decrease in obesity rates. Dentist prevalence also correlated with significantly lower obesity rates in counties where more than one quarter of children live in poverty.

“We found the first initial step of an association between higher prevalence of dentists and lower rates of obesity,” Canavan said. “Now we can really try to look and understand what is the causal relationship.”

While the study identifies dentists as potentially valuable players in obesity prevention, the researchers can only speculate about the mechanisms behind the correlation between dentists and obesity, Canavan said.

Holzer and Canavan posted a few explanations. People who go to the dentist, for example, may be more proactive in terms of health and less likely to consume sugar and become obese. Alternatively, dentists could be making a positive impact on their patients’ well-being by promoting healthy behaviors.

Jeannette Ickovics, a SPH professor who was not involved in the study, said the results are important because they identified factors that may lower the risk of obesity in individuals.

Although the study, which appears in the Sept. 1 issue of the Journal of the American Dental Association, establishd a correlational rather than a causal relationship, Canavan said it opens up new possibilities in obesity research, including studies of individual patients and dentists, longitudinal studies of communities over time and intervention studies where dentists actively educate their patients about obesity.

According to the Centers for Disease Control and Prevention, obesity affects 34.9 percent of adults in the U.S. and accounts for approximately $147 billion dollars in health care costs per year.