In this study, families were recruited from six sites across two states in northern Appalachia and invited to participate in an etiology study of their oral health. This report describes the recruitment strategies and study protocol.
With data from our study, we will be able to address many different types of hypotheses. For example, we will be able to examine the degree to which factors at a given level contribute to oral health status, such as whether tooth brushing, flossing, and a low sugar diet (individual level behaviors) are associated with less caries. In addition, we will be able to examine cross-level interactions. For example, tooth brushing (individual level behavior) and pit and fissure genes (genetics) may interact such that persons with poor brushing behavior and genes encoding deeper pits and fissures are at greater risk than persons with either risk factor by itself or the additive risk of the two risk factors. Furthermore, we will be able to examine more complex mediating pathways that cross multiple levels. For example, the pathway through which socioeconomic status (family level factor) is associated with caries could include brushing (individual level behavior), salivary flow (biologic factor) and microbial population (microbes). Finally, our hypotheses will not be limited to humans, because we will have access to genetic information about microbes as well.
Although there are many strengths to our study, there are weaknesses as well. For example, our study sample is drawn from volunteers; it is not a true random sample. However, this problem is mitigated by the approach of the current study in developing models that could be tested in future studies with true random samples. Such studies will be needed to evaluate the generalizability of our models. In addition, as yet we have no comparison group undergoing the same protocol. Thus we will be unable to address how our sample differs from non-Appalachians. To mitigate this weakness to some extent, we will be able to compare some of our data elements to nationally available data, and we are developing collaborations with other USA and non-USA cohort studies.
In sum, the aim of COHRA is to determine genetic, microbial, individual, family, and community factors that contribute to poor oral health status in Appalachia. We believe that there are trajectories of oral and systemic health and that an individual's trajectory may be determined early in life. Thus, we are particularly interested in the contributors to the oral health status of children. Our protocol is designed to examine factors hypothesized to contribute to children's oral health status at multiple levels [10
]. COHRA applies a family-based approach to the study of social and health-related factors impacting the oral health of children in Appalachia.