This investigation is the first to examine and report on the association of OHL with self-reported oral health status and dental neglect. We found that WIC clients with higher OHL were more likely to report excellent/very good oral health status versus good/fair/poor. There was a poor correlation between OHL and dental neglect. However, we found that lower SE was strongly correlated with dental neglect, and this association persisted after adjustment for age, race, education, dental use and OHL. Literacy, on the other hand, demonstrated a modest association with oral health status after controlling for age, race, education, and dental use.
The important role of self-efficacy in oral health status provides support to conceptual models that place “appropriate decision-making” between conceptual knowledge and oral health outcomes.35,43
Increased self-efficacy may be an enabling factor for individuals to engage in positive dental behaviors, which is consistent with theories of planned behavior,26
locus of control24
and the social cognitive theory.32
As illustrated in our conceptual model (), it is likely that personal characteristics such as self-efficacy mediate and/or modify the impact of literacy on oral health behaviors. We used the general self-efficacy measure instead of an oral health specific one. Although such instruments that could capture dental situation-specific dimensions have been developed and validated in dentistry,49–51
they have not been widely tested. In contrast this, the role of general self-efficacy as a determinant, modifier or moderator of health behavior change or maintenance is well-supported.33,34,52–55
Our data revealed a poor correlation between OHL and dental neglect. The construct of dental neglect was defined by Thomson and Locker41
as “failure to take precautions to maintain oral health, failure to obtain needed dental care, and physical neglect of the oral cavity.” This construct may be too narrow to encompass the entire spectrum of self-care, preventive attitudes and dental attendance altogether. Further work is warranted to identify these pathways that could be potential targets for oral health interventions.
Although the effect estimates for the association between OHL and SE with oral health status are small (PR of 1.02 and 1.05, respectively, in Model B), they correspond to one-point changes of these variables. Using these multivariate model-derived coefficients for the association of literacy and self-efficacy with oral health status, it is estimated that 10-unit increases of REALD-30 or SE scores correspond to PR= 1.25 (95% CL=1.05, 1.49) and OR=1.64 (95% CL=1.31, 2.06), respectively. Moreover, the “synergistic” interaction between literacy and self-efficacy in model C, although small in magnitude, indicated that the “effect” of literacy was more pronounced among individuals with higher SE, and vice versa.
The rationale for considering both effect mediation or modification is supported by the fact that the determination of a variable as a mediator is context-specific and requires prior knowledge or underlying theory that the variable of interest is on causal pathway between exposure and the outcome.36
Previous studies examining health behaviors have indeed considered SE both as a mediator and a modifier (moderator).56
In the context of OHL, no previous studies had examined the relationship between literacy and SE. While an association between health literacy and SE was not found in some previous studies in medicine,19,20
evidence from two recent investigations supports the link between literacy and SE.18,57
SE was found to be a strong correlate of oral hygiene behaviors among Australian dental patients.49
Although we did not conduct formal pathway analyses to support the proposed conceptual model, we did find a marked effect attenuation of the OHL-oral health status association when SE was entered in the model (contrast of models A and B). This indicates that OHL may confer its effect on oral health status via SE, as has been suggested for health literacy and health status.17,52
This finding should be interpreted with caution until future studies formally investigate these pathways. Similarly, when dental neglect was examined as the analytical endpoint, SE was significantly inversely correlated with neglect but OHL did not shown any material association.
Our finding of an interaction between literacy and self-efficacy constitutes evidence of effect modification that underscores the importance of considering both dental-specific and personality measures as correlates or antecedents of oral health behaviors and outcomes.31
Evidence indicates that SE may be improved via knowledge enhancement.58,59
Thus, providing individuals with the necessarily skills to obtain, understand and act upon dental-related information has the potential to increase their ability to cope with the demands of oral health maintenance and ultimately lead to improved oral health outcomes. Along these lines, Bandura60
has suggested that “belief in one’s efficacy to exercise control is a common pathway through which psychosocial influences affect health functioning”. Using this paradigm in planning interventions, depending on literacy or self-efficacy criteria, a determination could be made that certain individuals may benefit more from the use of visual materials to communicate key information, whereas others may benefit from behavior reinforcement and motivational interviewing (MI). MI is a patient-centered, directive therapeutic technique designed to enhance readiness for change by helping individuals explore and resolve ambivalence59
and potentially increase their coping skills.53
It is one intervention method that has been used successfully for the treatment of health-behavior based problems,62
and it has been recently tested in the dental arena as a preventive strategy among caregivers for the prevention of early childhood caries.63
Stewart et al59
as well as several recent investigations64–66
have described effective applications of such approaches in improving dental patients’ knowledge, self-efficacy and behaviors.
These results should be considered in light of the study’s limitations. The data were collected from a non-probability convenience sample of clients from the NC-WIC clinics. Our sample characteristics prevent generalization of results beyond female WIC clients enrolled in WIC and attending the specific clinics in NC during the time of this study. Future research should draw from a population-based probability sample. REALD-30 has been validated in English only, so our recruitment was limited to English-speaking patients. Also, our measurement of OHL is based on a word recognition test.37
While word recognition instruments measure only selected aspects of literacy skills and are not comprehensive, comparable word recognition instruments have been used with success in medicine and they are correlated strongly with reading fluency. Our initial investigations compared the REALD-30 versus a dental functional health literacy test and found a high correlation between the two.67
More recent reports comparing functional literacy estimates with word recognition and numeracy assessments have also confirmed the high correlation between these measures.68
Although our subjects were recruited from a non-probability, convenience sample of NC-WIC clients and thus may have limited external validity, we feel that this population is an important one to examine. WIC was established by the Food and Nutrition Services of the Department of Agriculture (USDA) to target low-income women, infants, and children who are at risk nutritionally. WIC’s goal is to improve the health outcomes of its clients by providing nutritious foods, nutritional education, counseling, and medical/dental referrals to facilitate good health care during pregnancy, the post-partum period, infancy, and early childhood. WIC has a huge reach, serving over 9.1 million individuals annually and over a third of all infants born in the US today.69
WIC is often the first contact with the healthcare system for the poor. Because of its repeated contact with vulnerable populations, WIC is uniquely positioned to identify families with low health literacy.
In summary, to date research in OHL has been based on only a few studies of care-seeking subjects. This investigation is the first to report on the relationship of OHL, self-efficacy, dental neglect and self-reported oral health status in a cohort of participants in a large public health program. Based on our findings, we advocate for the consideration of personality traits, such as self-efficacy, with OHL, as risk factors or screeners for poorer oral health outcomes and in planning of oral health intervention programs.