A Look at Oral Health Disparities in Appalachia

March 2009

In many parts of Appalachia, tooth decay remains an unfortunate rite of childhood that too often leads to a lifetime of poor oral health.  In West Virginia, population 1.8 million, dentists pulled an estimated 31,800 children’s teeth in 2006.  By age 65, about 40 percent of the state’s retirees have none of their natural teeth remaining.  Given the troubling scope and consequences of this largely preventable problem across Appalachia, researchers are now attempting to more clearly define the causes of poor oral health in the region and develop practical, low-cost solutions.  Prominent in this effort is the Center for Oral Health Research in Appalachia (COHRA).  For an overview of this NIDCR-supported project, we recently spoke to Mary Marazita, Ph.D., a scientist at the University of Pittsburgh and co-principal investigator of COHRA.

The center was established in 2000 by the University of Pittsburgh, in partnership with West Virginia University.  We’re trying to understand why oral health remains so poor in the Appalachian region.  To the best of our knowledge, a comprehensive analysis of oral health in Appalachia has never been undertaken, so, we’re navigating largely uncharted research territory.

Once the territory is charted, what might be the outcome?

Our goal is to develop practical, low-cost strategies that are specifically tailored to life in Appalachia and which effectively promote good oral health. 

When you say Appalachia, which American states are we talking about?

Appalachia stretches from southern New York down to parts of Mississippi.  But COHRA is focused specifically on oral health disparities in parts of West Virginia and Pennsylvania.

We have COHRA research sites in Webster and Nicholas counties in central West Virginia.  In western Pennsylvania, we have sites in Allegheny, Washington, and McKean counties. 

All four counties are primarily Caucasian.   Many families can trace their lineages back to the Scots-Irish immigrants who settled the region generations ago.  Like much of Appalachia, the counties are fairly mountainous, remote, and struggle economically.  A lot of people still live out of town on farms or family land, where the well water naturally contains little or no fluoride.  We ask our participants to bring in water samples from their homes, and that allows us to test the fluoride levels.  In West Virginia, the water generally has very little fluoride.  In Pennsylvania, that’s not the case, as most households are located in areas with fluoridated water.

Does that mean the West Virginians have higher rates of decay? 

Well, the answer is kind of interesting.  Speaking anecdotally, we see similar rates of decay at our West Virginia and Pennsylvania sites.  Of course, it’s very well established that fluoride reduces the incidence of caries.  That’s not at issue here at all.  But in some instances, we’ll see individuals from fluoridated communities who still get caries, and people from non-fluoridated sites who have perfect teeth.  That tells us that, we still need to account for additional factors in Appalachia that cause or contribute to caries, periodontal disease, and other oral conditions.

And how do you go about teasing out these additional factors?

To start, you absolutely must look at each individual within the context of his or her family.  One of our most striking findings to date is that the oral health disparity begins very early in life.  We see tooth decay in children as early as age one and at a rate within this age group that certainly surpasses the national average.  Interestingly, once the disparity is established, it doesn’t necessarily lead to rampant decay.  But the overall increase in decay that is seen in our study population, compared to the rest of the nation, typically remains steady throughout childhood and into adulthood. 

So clearly solving the disparity is not as simple as passing out toothbrushes.  You must start by educating parents on how to protect their baby’s oral health.  

Exactly.   We want to instill the idea that relatively simple measures can help a baby keep his or her teeth for a lifetime without decay, without chronic pain, and without the social stigma that comes with having bad teeth.  To convey this message, though, often means taking into account another critical family issue.

Income.  So many families in these counties must focus first and foremost on putting food on the table.  If money is tight at home, healthcare often takes a backseat.  In our interviews with adults, we’ve found good oral health often ranks low on their list of healthcare priorities.  It doesn’t have to be that way.  In fact, it shouldn’t be that way.  As I mentioned, the means to good preventive oral health measures are inexpensive and relatively simple to use.  We need to reinforce this message and raise the status of prevention as an everyday priority. 

Does one’s community also contribute to the disparity?

That’s a very important point.  In addition to familial factors, you must consider each individual within the context of his or her community.  I’ve already touched on fluoridated water, which is a community issue.  But access to dental care is another community issue that can contribute to the disparity.  It can be extremely difficult for rural communities to recruit dentists.  Without a dentist in town, people must go out of their way to find treatment.  That can make it easier to ignore a decayed tooth, and, as we know, a once easily treatable dental problem can become extremely painful and prohibitively expensive.

Has being embedded in the community had a positive impact on patient recruitment?

It certainly has been helpful.  But we’ve faced a learning curve, too, in recruiting volunteers. 

How so?

Originally, we gave brief presentations at health centers, churches, and the local WalMart.  We assumed news of the study would spread in the community, and our recruitment goals would be met.  Well, our assumption wasn’t necessarily incorrect.  People did hear about our study.  But we soon found most of those who volunteered were women and their children.  That presented a problem because our goal was to recruit 500 families.  In other words, we were getting the moms, but we weren’t getting the dads. 

What did you do?

We started offering gift certificates from a local sporting goods store and other businesses in the community that connected with a dad’s day-to-day interests.  But as more fathers came to the clinic, we ran into another problem. 

What’s that?

Literacy.  We asked enrollees to fill out a few questionnaires at the beginning of the enrollment process that gave us information about their families, community, and personal behaviors.  We quickly discovered that some of the participants really struggled to get through the paperwork in a reasonable amount of time.  They would come in and just wouldn’t want to stay for the time that it took them to read through and answer the questionnaires.

That must have been unexpected?

Sure, in this day and age, it surprised us a bit.  We put our heads together and decided to upload the questionnaires onto tablet PCs.  The computers are equipped with a program that converts text into audio.  After the father reads and hears the question on the screen, he can push a button to give his response.  That means nobody has to sit there anymore and grapple with reading the text.  That’s helped a lot with recruitment.

Have you met your recruitment goals?

Absolutely.  Our goal was to enroll 500 families and 2,000 individuals.  We’ve now enrolled nearly 600 families and 2,800 individuals.

In addition to the above-mentioned psychosocial aspects of the study, you’re also pursuing the biological components that may contribute to the disparity.  Tell me about these arms of the study.  

There are two main biological arms:  genetics and microbiology/immunology.  Let me start with the genetics.  We are one of eight studies funded under the NIH Genes and Environment Initiative to perform genome wide association studies, or GWAS, on a complex human trait.  In this case, we’re looking for genes that might be involved in tooth decay.  This marks the first time a GWAS approach has been applied to a dental disorder.   I should mention that this work builds in part on the observation that I noted earlier: Why do some people from fluoridated communities develop decay, and some from non-fluoridated have perfect teeth?  A genetic component is likely involved, and the GWAS studies will begin to pull out the genetic pieces for further study.

GWAS studies are a relatively new phenomenon in genetics, is that right?

Well, they’ve been around a couple of years now.  As one of the byproducts of the Human Genome Project, the cost of DNA analysis has dropped under a penny per base, or unit of DNA.  This has cleared the way to affordably and also rapidly characterize, or genotype, DNA samples from hundreds of people with a predisposition to a specific disease.  By typing single nucleotide polymorphisms, or variations, throughout the entire genome, GWAS studies tend to find shared sequence variations in places that are totally unexpected and which other techniques would never find. 

In the meantime, we’re already testing candidate genes, or genes that we think might be involved in caries, either based on animal models or from our best guesses.  We’re looking at genes for proteins found in the saliva and genes for tooth structure elements, such as enamel structure.  We’re also looking at taste preference genes.  There are genes for whether you prefer sweet or sour tastes.  We’re also looking at behavioral genes.  Behavioral genes are known to influence self-regulatory behavior, and taking care of your teeth is one of the first self regulating behaviors that children learn.  We think that if you have different alleles, or sequences, at those behavioral genes, you may well have different oral health outcomes.  Oral health is a complex combination of genes, your microbial flora, your behaviors, and the available healthcare. 

What about the microbiology/immunology arm?

We’re characterizing many of the usual microbial suspects in oral disease.  For dental caries, that’s the bacterium S. mutans.  For periodontal disease, there are the bacteria P. gingivalis, T. forsythia, and a couple of others.  So we’re doing semi-quantitative measures as part of our microbiology profile of all families.  In addition, we’re doing detailed genetic analyses of S. mutans to characterize the strains found in our high-disease versus low-disease families.  We are also exploring the sharing of specific S. mutans strains within families, particularly between mother and child. So, we’re trying to see if exactly the same genetic profiles are seen in the bugs between parents and children and between siblings.  There’s also the notion that in families with high levels of disease, you’ll see more diversity both at a genetic level and in the various types of S. mutans that are present in the mouth. Our next step will be to apply metagenomic approaches that broadly sample the microbial genes expressed at any one time in the mouth.  We will cast a wide net across the microbial spectrum, from high to low abundance bacteria.

How might this be translated into improved care?

Our results will translate into what many now call “personalized dentistry.”  In other words, the specificity of our biological discoveries will lead to improved diagnostics and more tailored care.  As we’ve already mentioned, fluoride is great.  But, when you’re in a community that has limited access to oral healthcare, then you need to think of additional ways to address the disparity.  The more tools there are in the toolbox, the greater potential we will have to help people and make a difference in their lives. 

Thanks for talking.

Glad to do it.