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.

  • Mark In FLorida

    Could it be that people who don’t watch their diet don’t go to dentists either?

    • Alan_McIntire

      I think that’s the most likely possibility. People unconcerned about oral hygiene are also unconserned about overall health and fitness

  • John Hockert

    Has anyone thought that, in the U.S. obesity is more common among lower income people and lower income people are less like to visit dentists. Thus, dental offices would be more dense in more affluent neighborhoods where there is more business. Thus, the common sense correlation between density of dentist offices and lower obesity rates.

  • wcvarones

    I guess they don’t teach about spurious correlation anymore at Yale.

  • Forbes

    Correlation is not causation is learned in statistics 101. The suggestion re: dentists is mind-bogglingly inane.

  • Douglas1234

    Correlation . . . causation . . . tom-AY-to . . . to-MAH-to

  • Chris Barnard

    Excellent motivation…Stop eating so much & exercise, or see the dentist!

  • Hieronymus Machine

    Oh c’mon you guys! You know they’re right: Higher grades = smarter students; more college degrees = higher pay; more homeowners = higher wealth; and more dentists = lower obesity rates. Duh!

  • Hieronymus Machine

    Shared this article, so just passing on her comment: “Be careful: flood the place with too many dentists and some people could STARVE!”

  • decisivemoment

    If there is a causation at all, I suspect it’s going to be found somewhere in the realm of oral health. You don’t floss, you don’t keep up with your teeth, and the result is constant inflammation and not just in your mouth as well as overall poor health, and sick and inactive people tend to be heavy. If this is in fact the connection, then the dentist would merely be one more gatekeeper to add to the thousand others (e.g. parental upbringing, availability of primary health care, personal training, online fitness programs, the marketing of personal health products, preventative health plans, health education etc.) preventing this outcome from happening. This would presumably explain the combination of statistical significance but a very low coefficient (i.e. a low marginal effect).