Compounding these sobering statistics is the fact that a substantial proportion of people with identified risk factors for CVD have not been diagnosed with CVD or are treated inadequately. Recent estimates from the Third National Health and Nutrition Examination Survey (NHANES III) indicated that among insured people, 29 percent of adults with hypertension and 51 percent of adults with hypercholesterolemia had undiagnosed CVD; among the uninsured, 41 percent had undiagnosed hypertension, and 71 percent had undiagnosed hypercholesterolemia.² The Seventh Report of the Joint National Committee on Prevention, Detection, Evaluation, and Treatment of High Blood Pressure found that one in four adults is hypertensive, with the majority of them not adequately controlling the disease.³

Researchers have identified a number of well-documented risk factors for CVD, including age, high cholesterol levels, high blood pressure, smoking and diabetes.⁴ Data support the efficacy of early detection of people at risk of developing CVD and the institution of both primary and secondary prevention strategies as a means of reducing the impact of the CVD burden. In accordance with these data, the American Heart Association recommends that coronary heart disease (CHD) risk be assessed every five years for adults 40 years or older with no history of CVD.⁵ However, previous research among primary care providers has shown that CVD risk assessment is inadequate.⁶ In addition, while many people visit their dentists on a regular basis for routine and preventive dental care, they are not screened for CVD and many only go to their physicians when they exhibit clinical signs and symptoms. Achieving effective CVD risk assessment in the general population requires a multidisciplinary approach involving establishing adequate screening methods by different health care providers to identify people at risk of developing CVD.³ Routine health screenings performed by oral health care providers can be extended to systematically screen for particular diseases, such as CVD.⁷ This would provide dentists with the opportunity to screen for significant systemic disease risks among a population that would not otherwise seek medical care.

Global risk assessment tools have been developed to facilitate precise and systematic evaluation of a patient’s five- to 10-year risk of experiencing a coronary heart disease event.

While individual risk factors for CHD warrant prevention efforts, assessment of global risk based on multiple factors is more effective for identifying high-risk patients who could benefit from primary prevention efforts. Several global risk assessment tools have been developed to facilitate precise and systematic evaluation of a patient’s five- to 10-year risk of experiencing a CHD event. The most widely recommended for use in the United States is the Framingham-based risk calculation, which assesses the 10-year risk of experiencing a CHD event, such as acute angina or myocardial infarction.⁸ The Framingham-based risk calculation is a discriminating CHD risk assessment tool that has been validated in multiple, diverse population groups.^9–13

The first step in considering the potential impact of targeted CHD risk screenings by oral health care providers is to determine the number of people who could benefit from such a program. We used the most recent NHANES data to determine the proportion of people who are at increased risk of experiencing a cardiovascular event; who have no history of CHD, heart attack, stroke or angina and no reported diagnosis of hypertension or high cholesterol levels; and who had not seen a physician in the last year but had visited a dentist.

NHANES. The Division of Health Examination Statistics, National Center for Health Statistics of the Centers for Disease Control and Prevention has been conducting National Health and Nutrition Examination surveys periodically since 1971. NHANES is a stratified, multistage probability sample of the noninstitutionalized, civilian U.S. population. The stages of the sample selection process are

– primary sampling units made up of contiguous counties or small groups of contiguous counties;

– household clusters (blocks or groups of blocks) within the primary sampling units;

– households within clusters;

– one or more participants within the households.

NHANES data collection consists of three main components: the household interview survey, the clinical examination survey and the laboratory tests. Trained interviewers collect the household interview data in the survey participant’s home, and the health examination survey data are collected in mobile examination centers. Household interview data are collected using a computer-assisted personal interview system. All equipment and data collection systems are calibrated before the start of survey data collection. Each year, approximately 7,000 people of all ages are interviewed for the household component, and approximately 5,000 of these participants complete the clinical examination component.

For the 1999–2000 and 2001–2002 NHANES periods, a total of 21,004 participants were interviewed for household data; 10,291 of these underwent clinical examination and testing at a mobile examination center.

Framingham-based coronary heart disease risk calculation. The Framingham-based risk calculation is a CHD risk algorithm using sex, age, history of smoking, and measurements of blood pressure and total and high-density lipoprotein cholesterol levels to predict a 10-year global risk score for developing a CHD event.¹⁴ The algorithm incorporates the recommended categories for blood pressure from the Fifth Report of the Joint National Committee on Detection, Evaluation, and Treatment of High Blood Pressure¹⁵ and cholesterol levels from the National Cholesterol Education Program¹⁶ into a multivariate CHD prediction model. The algorithm was developed in 1998 using data collected during a 12-year, population-based, longitudinal study of the development of CHD among 2,489 men and 2,856 women who had an initial study visit between 1971 and 1974.¹⁴ Cox proportional hazards regression models were used to assess the relationship between selected independent variables and CHD; multiple combinations of risk factors were used to develop various prediction models. The 12-year follow-up data were used in the proportional hazards regression models to determine 10-year CHD incidence estimates using multiple risk factors. Separate score sheets for prediction of CHD events for men and women were developed, and points were assigned for each risk factor based on the beta coefficients of the regression analysis. The normal and abnormal levels of low-density lipoprotein and high-density lipoprotein cholesterol are similar to those in guidelines set forth by the National Cholesterol Education Program, Adult Treatment Panel III.¹⁶

A Framingham-based risk score of higher than 10 percent for adults 40 years or older is considered a moderate, above-average risk of experiencing a CHD event within the next 10 years.¹⁷ A Framingham-based risk score of 20 percent or higher is considered a high risk of experiencing a CHD event within the next 10 years.¹⁷

	SUBJECTS AND METHODS

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We used the most recently available public-use data files (1999–2000 and 2001–2002) from the 1999–2004 NHANES to determine the percentage of undiagnosed people in a randomly selected, representative sample of the 2000 U.S. census adult population who are at risk of experiencing a CHD event.¹⁸ We followed the most recent analytic guidelines (June 2004) for this analysis.¹⁹ We conducted the analysis using SAS-Callable SUDAAN version 9.0 (Research Triangle Institute, Research Triangle Park, N.C.) and SAS system for Windows version 9.1 (SAS Institute, Cary, N.C.). The specific NHANES questions we used are listed in the Box.

	RESULTS

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Demographic, clinical, household questionnaire and laboratory data were available for 10,291 NHANES subjects from the 1999–2000 and 2001–2002 survey periods. Of these, 6,059 (58.9 percent) were 40 years or older. Of the 6,059 participants 40 years or older who participated in all NHANES components, 3,005 (49.6 percent) were men and 3,054 (50.4 percent) were women. We conducted a number of sampling steps to reach the final study sample. We provide details of the sampling distribution separately for men and women.

Of the 3,005 men, 28.7 percent had no reported risk factors of interest (that is, hypertension, high cholesterol levels, angina, heart attack, stroke or CVD) (Table). A total of 21.2 percent of the "no reported risk factors of interest" cohort had not seen a physician in the previous 12 months, and 54.8 percent of the "no reported risk factors of interest and did not see a physician in the previous 12 months" cohort had seen a dentist in that same period. Of the 3,054 women, 27.8 percent had no reported risk factors of interest; 6.6 percent of the "no reported risk factors of interest" cohort had not seen a physician in the previous 12 months, and 58.7 percent of the "no reported risk factors of interest and did not see a physician in the previous 12 months" cohort had seen a dentist in the same period.

Given that only one woman had an increased 10-year CHD risk, we extrapolated the results to the U.S. population only for men. According to the 2000 U.S. census data, there were 54,454,315 men aged 40 to 85 years, the age range corresponding to the NHANES age range (Figure). Applying the study percentages for each sampling step to the U.S. male population generated a total of 332,262 men (18.3 percent of men 40 to 85 years of age) who reported no risk factors of interest and had not seen a physician but had seen a dentist in the previous 12 months, and who had a greater than 10 percent risk of experiencing a CHD event in the next 10 years. A total of 259,636 men (14.3 percent) had a moderate, above-average risk (> 10–< 20 percent) of experiencing a cardiovascular event within 10 years, and an additional 72,625 (4.0 percent) had a high ( 20 percent) risk of experiencing a cardiovascular event within 10 years. This population could benefit from primary prevention efforts aimed at diminishing or ameliorating cardiovascular risk.

View larger version (57K): [in this window] [in a new window]   Figure. Application of study algorithm to 2000 U.S. census data. *Adjusted percentage with increased global 10-year risk of experiencing a coronary heart disease (CHD) event among men aged 40 to 85 years with no reported history of CHD, heart attack, angina or stroke and no reported diagnosis of high cholesterol levels or hypertension who had not seen a physician in the previous 12 months but had seen a dentist.

	DISCUSSION

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Health care utilization patterns indicate that seeking routine and preventive care on a regular basis is a more typical pattern for oral health care than it is for medical care. Given that more than 18 percent of men in our study were unaware of their increased risk of experiencing a CHD event and a substantial number did not visit their physicians in the previous year but had seen their dentists during that period, there is a unique opportunity for dentists to participate in targeted cardiovascular screening activities to augment identification of patients with increased CHD risk who could benefit from primary prevention activities.

Conducting medical history reviews and measuring patients’ blood pressure are common practices performed by dentists. These procedures are performed primarily to identify contraindications or assess the need for implementing modifications to dental treatment. A second benefit gained by performing these evaluations, however, is the monitoring of underlying medical conditions.

Our study clearly suggests that dentists can play an important role in primary prevention of CVD. Such an undertaking can improve the overall health of patients, but may involve tasks that are not performed routinely in dental offices and may not directly affect the provision of dental care. Moreover, it is not clear if patients will consent to have dentists screen for CVD or any other systemic condition when they perceive such a screening as having little or nothing to do with their oral health. This may become an even greater concern when a blood test is part of the screening. Another concern may be the issue of reimbursement for nondental-related activities performed by an oral health care provider. It is important to realize that at the present time a dentist can screen for CHD but should, when indicated, refer patients for more in-depth evaluation, diagnosis and treatment by a physician.

	CONCLUSIONS

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We conducted our study to ascertain if dentists may be able to identify people at risk of experiencing CHD events who are asymptomatic, have not been told by a physician that they are at risk of developing CHD and have not seen a physician within the past year. We made no attempts to calculate the financial impact of such an endeavor or ascertain if such screenings could be performed routinely in a dental setting. We hope that this study will encourage further research into the role of dentists and the impact of routine screenings on the general health of their patients.