Introduction
The study of Epidemiology is the basis of public health research and offers the tools necessary to understand the process of disease occurrence, spread and effective control within a population. Epidemiology is an important part of the discipline of dentistry and oral health sciences, and is applied to determining risk factors, monitoring disease prevalence like dental caries and periodontal disease, and assessing the efficiency of disease-prevention efforts.
In this arena, language is significant. Scientific communication is based on a common language for clear and precise communication. It’s easy to have many misconceptions about epidemiology, including about research papers written in the field of epidemiology, systematic reviews, and public health announcements.There are all sorts of misunderstandings to contend with if you don’t understand the epidemiologic terminology.
By focusing on the front line of human health – the mouth – oral health epidemiology is especially relevant because oral diseases are one of the most prevalent chronic diseases globally. The World Health Organization (WHO) has estimated that almost 50% of the world’s population suffers from oral diseases, which calls for standardised terminology for accurate reporting and comparison around the world.
The article describes key terms that are encountered in epidemiologic research studies and specifically in oral health studies, to enable students, oral health care providers, and researchers to better understand and participate in scholarly conversations regarding dental epidemiological information.
Some Key Epidemiology Information on Oral Health.
Epidemiology is the investigation of the distribution and determinants of health related states in populations. When used in oral health, it includes the patterns of the following diseases:
- Dental caries
- Periodontal (gum) diseases
- Oral cancers
- Developing abnormalities and malocclusion
One aim of epidemiologic research is to know the prevalence of these illnesses and to determine the cause and possible prevention of these diseases.
An excellent resource for some background information on this topic is the Global Oral Health epidemiologic research related to oral health, which gives an overview of oral health globally, and points to the burden of oral diseases and the risk factors for oral disease worldwide. Researchers can gain insight into epidemiologic data in a larger public health narrative when they consider this context.
Why Epidemiological Vocabulary.
Epidemiologic terms are characterized not only by their academic use but also by their precision as a tool. A misinterpretation of any of these phrases can result in erroneous conclusions of disease risk, efficacy of disease treatment, or the general health condition of a population.
For instance, there is the potential for misinterpretation of the terms prevalence and incidence, i.e., that the disease may be new or merely abundant. Similarly, there is a major risk of misinterpreting risk ratio versus odds ratio, which can result in misinterpretation of the strength of association between a risk factor such an adult’s use of sugar and dental caries.
Standardized vocabulary, especially in oral health research is essential to:
- Consistency across studies
- Population fidelity testing of precise comparisons
- Comprehensive understanding of clinical trials.
- The improvement of public health decision-making.Better public health decisionmaking.
In the end, the language of epidemiology enables scientists and practitioners to be able to communicate about the same science in the same “dialect.”
Epidemiologic Terms in Oral Health Research.
Incidence
Incidence is the number of new cases of a disease that develop among a population during a particular time. The incidence in oral health can be used to quantify the onset of new dental caries in children over one school year.
Incidence allows researchers to focus on the onset of disease, not the prevalence of cases, and so also helps to identify risk factors.
Prevalence
Prevalence is the total number of cases (new and existing) of a disease in a population at a specific point in time. For instance, the prevalence data will be available for the adult population if one measures the percentage of adults in a community that now suffer from periodontal disease.
The prevalence is particularly useful for determining the overall burden of oral diseases.
Morbidity
Morbidity: Disease or illness present in a population. In terms of dentistry, morbidity may refer to the amount of decay or inflammation in the gums, or to be able to lose teeth.
The differences between morbidity and mortality can be summarized by saying that while mortality is more concerned with the outcome of death, morbidity is meant to stress the quality of the health.
Mortality
Mortality is the incidence of death due to a disease in a population. Oral diseases do not often have direct mortality, except for oral cancer, which is a leading direct cause of death and is frequently part of epidemiologic studies of mortality.
Risk Factor
A risk factor is any characteristics or exposure that makes one more likely to be at risk for developing a disease. Common risk factors for oral health problems are:
- High sugar intake
- Poor oral hygiene
- Tobacco use
- Poor access to dental services
To prevent dental issues, it’s crucial to understand risk factors.
Measures of Disease Frequency and Burden.
Relative Risk (Risk Ratio)
Relative risk is the ratio of the frequency of diseases in an exposed group to the frequency of disease in a non-exposed group. For instance, it could compare the risk of dental caries in children drinking sugary beverages versus non-sugary.
An RR > 1 is a risk factor and an RR < 1 is a protective factor.
Odds Ratio
The odds ratio is a statistic used mainly in case-control studies. It is the relative risk of exposure of those who have the disease to those who don’t. Oral epidemiology could study the connection between periodontal disease and smoking.
The odds ratio is similar to relative risk, but can be particularly helpful in studies of rare diseases.
Attributable Risk
Risk from an exposure, called the attributable risk, quantifies the fraction of disease directly due to that exposure. For instance, it can calculate how much decay would be avoided if there were to be less sugar.
This measure is significant to issues of public health planning.
Research Proposals Focus on Epidemiology.
Cross-Sectional Studies
Data gathered at one single time or place is referred to as cross sectional. They are widely employed when carrying out oral health surveys to estimate the prevalence of oral health conditions such as untreated caries or gum disease.
They are helpful to recognise patterns but cannot prove causes.
Cohort Studies
Cohort studies are conducted on a group of people over a period of time to determine the impact of an exposure on the outcome. For instance, children’s dietary patterns might be followed over several years with the detection of the appropriate changes in the progression of dental caries.
The studies are effective in determining cause-and-effect relationships.
Case-Control Studies
Case control studies look at the past exposures of a group of people who have a disease (cases) compared to those without a disease (controls). This could be, for example, in the field of oral health research, where something might be checked for differences in risk factors, such as those associated with tobacco use, between patients with oral cancer and patients without.
It’s efficient in the study of rare diseases.
Bias and Confounding in Oral Health Research
Bias
Bias: Errors that happen consistently and incorrectly. Bias can be found in the collection of the data, selection of the participants or reporting in oral epidemiology.
Common types include:
- Study participants are not representative of the population (selection bias)
- Measurement Bias: may relate to the way data/measurements are gathered, which can be inaccurate.
- Hindsight bias: when participants cannot clearly remember behaviors from the past accurately
Confounding
Confounding: this is when an extraneous factor/condition, apart from the exposure and outcome, affects the observed relationship between them, resulting in an incorrect overlap. For instance, socioeconomic status has been shown to be a confounder in any association between food intake and dental caries since both nutrition and the availability of dental care are influenced by socioeconomic status.
Good study design and a scientific analysis of the data controls confounds
Analysis of Epidemiologic Data in Oral Health
Reading the numbers of an epidemiologic finding is not enough to interpret the information, it means being able to account for context, method, and limitation.
In reviewing the oral health studies, take into account:
- Sample size, and characteristics of the population
- Study plus design and studies; and how long.
- Use of measurement instruments including (e.g., DMFT index for caries)
- Difference between a statistical significance and clinical relevance.
- There are possible sources for bias.
An informed interpretation facilitates better application of the results of research in therapeutic care of patients and public health interventions.
With an increasing evidence-based approach to treatment guidelines in dentistry, it is important that the practitioner is also knowledgeable about the principles of epidemiology.
Role of Epidemiology in Improving Oral Health
Epidemiologic studies play a key role in understanding oral health and disease around the world and increasing the chances of achieving better outcomes. It tells the policy makers how things can look like:
- Fluoridation of community water supply (CWS) programs.
- Dental screening programs in schools.
- Tobacco control regulations
- Sugar reduction campaigns
Epidemiology is the analysis of the pattern of diseases to guide the development of preventive strategies that decrease the burden of oral diseases worldwide by identifying risk factors.
Conclusion
Anyone working in the field of oral health research or clinical practice should have a grasp of the epidemiology terminology. The concepts of incidence, prevalence, risk factors and study design may seem academic, yet they are terms that could affect the interpretation and application of data.
These terms are crucial to understand when evaluating research, participating in oral presentations of scientific research, and providing recommendations based on scientific evidence. Oral disease remains a major health problem worldwide and pivotal to enhancing research and the health of the population is understanding how to speak the epidemiologic language.
