Periodontitis Among Adults Aged ≥30 Years — United States, 2009–2010

Gina Thornton-Evans, DDS1

Paul Eke, PhD2

Liang Wei, MS3

Astrid Palmer1

Refilwe Moeti, MA4

Sonja Hutchins, MD5

Luisa N. Borrell, DDS6

1Division of Oral Health, National Center for Chronic Disease Prevention and Health Promotion, CDC

2Division of Population Health, National Center for Chronic Disease Prevention and Health Promotion, CDC

3DB Consulting Group, Inc.

4Division of Heart Disease and Stroke Prevention, National Center for Chronic Disease Prevention and Health Promotion, CDC

5Office of Minority Health and Health Equity, CDC

6Department of Health Sciences, Lehman College, City University of New York, Bronx, New York

Corresponding author: Paul Eke, Division of Population Health, National Center for Chronic Disease Prevention and Health Promotion, CDC. Telephone: 770-488-6092; E-mail: peke@cdc.gov.

Introduction

Periodontal disease, or gum disease, is a chronic infection of the hard and soft tissue supporting the teeth (1) and is a leading cause of tooth loss in older adults (2). Tooth loss impairs dental function and quality of life in older adults (2). The chronic infections associated with periodontitis can increase the risk for aspiration pneumonia in older adults and has been implicated in the pathogenesis of chronic inflammation that impairs general health (3,4). The severity of periodontal disease can be categorized as mild, moderate, or severe on the basis of multiple measurements of periodontal pocket depth, attachment loss, and gingival inflammation around teeth (5).

At the national level, monitoring the reduction of moderate and severe periodontitis in the adult U.S. population is part of the health-promotion and disease-prevention activities of Healthy People 2020 (6). Approximately 47% of adults aged ≥30 years in the United States (approximately 65 million adults) have periodontitis: 8.7% with mild periodontitis, 30.0% with moderate, and 8.5% with severe periodontitis (7). Periodontitis increases with age; adults aged ≥65 years have periodontitis at rates of 5.9%, 53.0%, and 11.2% for mild, moderate, and severe forms, respectively (7). As the U.S. adult population ages and is more likely to retain more teeth than previous generations, the prevalence of periodontitis is expected to increase and consequently could increase the need for expenditures for preventive care and periodontal treatment (8).

Periodontitis is directly associated with lower levels of education and higher levels of poverty, both of which influence the use of dental services by adults (9–12). Educational attainment and poverty might mediate significant differences in the prevalence of periodontal disease between different racial/ethnic populations. Smoking and some chronic diseases such as diabetes are important modifiable risk factors for periodontitis (13). Since the early 1960s, U.S. national surveys have assessed the periodontal status of adults (14). However, the validity of estimates from these surveys has been limited by the use of partial-mouth periodontal examination protocols, which significantly underestimate the prevalence of periodontitis (15–17). The 2009–2010 National Health and Nutrition Examination Survey (NHANES) cycle is the first to include a full-mouth periodontal examination for U.S. adults (aged ≥30 years) and provides the most direct evidence for the true prevalence of periodontitis in this population.

This report is part of the second CDC Health Disparities and Inequalities Report (CHDIR). The 2011 CHDIR (18) was the first CDC report to assess disparities across a wide range of diseases, behavioral risk factors, environmental exposures, social determinants, and health-care access. The topic presented in this report is based on criteria that are described in the 2013 CHDIR Introduction (19). This report provides information concerning disparities in periodontitis, a topic that was not discussed in the 2011 CHDIR (18). The purposes of this periodontitis in adults report are to discuss and raise awareness of differences in the characteristics of people with periodontal disease and to prompt actions to reduce these disparities.

Methods

To examine racial/ethnic disparities in the estimated percentage of adults aged ≥30 years with periodontitis by age, sex, education, poverty levels, and smoking status, CDC analyzed data from the 2009-2010 NHANES cycle. NHANES is a cross-sectional survey designed to monitor the overall health and nutritional status of civilian, noninstitutionalized U.S. population. NHANES uses a stratified multistage probability sampling design. For 2-year data cycles, NHANES surveys a national representative sample. The technical details of the survey, including sampling design, periodontal data collection protocols, and data, are available online (http://www.cdc.gov/nchs/nhanes.htm). A total of 5,037 adults aged ≥30 years participated in the survey, and 951 were excluded for medical reasons or incomplete oral examinations. In this analysis, 343 edentulous participants were excluded, leaving a total of 3,743 participants, representing a weighted population of approximately 137.1 million civilian noninstitutionalized U.S. adults. The findings in this report cannot be compared with those of previous studies using NHANES data (9,10) because the case definitions and age range used in this analysis differed.

All periodontal examinations were conducted in a mobile examination center by dental hygienists registered in at least one U.S. state. Gingival recession was defined as the distance between the free gingival margin and the cementoenamel junction; pocket depth was defined as the distance from free gingival margin to the bottom of the sulcus or periodontal pocket. These measurements were made at six sites per tooth (mesiobuccal, midbuccal, distobuccal, mesiolingual, midlingual, and distolingual) for all teeth except third molars. For measurements at each tooth site, a periodontal probe (Hu-Friedy PCP 2) with graduations of 2 mm, 4 mm, 6 mm, 8 mm, 10 mm, and 12 mm was positioned parallel to the long axis of the tooth at each site. Each measurement was rounded to the lowest whole millimeter. Data were recorded directly into an NHANES oral health data management program that instantly calculated attachment loss as the difference between probing depth and gingival recession. Bleeding from probing and the presence of dental furcations were not assessed.

Periodontal measurements were used to classify participants as having mild, moderate, or severe disease by using standard case definitions for surveillance of periodontitis (4); total prevalence of periodontitis in the population was calculated by combining prevalence of mild, moderate, and severe periodontitis. Severe periodontitis was defined as having two or more interproximal sites with ≥6 mm attachment (not on the same tooth) and one or more interproximal sites with ≥5 mm pocket depth. Moderate periodontitis was defined as two or more interproximal sites with ≥4 mm clinical attachment (not on the same tooth) or two or more interproximal sites with pocket depth of ≥5 mm (not on the same tooth). Mild periodontitis was defined as two or more interproximal sites with ≥3 mm attachment and two or more interproximal sites with ≥4 mm pocket depth (not on the same tooth) or one site with ≥5 mm.

Race/ethnicity was self-reported; for this analysis, three race/ethnicity groups, each with a sample size large enough to ensure statistically reliable estimates, were used: non-Hispanic white, non-Hispanic black, and Mexican-American. Poverty status categories, or percentage of poverty relative to the federal poverty level (FPL), was based on family income, family size, and number of children in the family, for families with two or fewer adults, and on the age of the adults in the household. Families or individuals with income below their appropriate income thresholds, as determined by family size and composition, were classified as living below the FPL. The income thresholds are updated annually by the U.S. Census Bureau (available at http://aspe.hhs.gov/poverty/11poverty.shtml). Education was classified as less than high school, high school graduate or equivalent, and greater than high school. Smoking status was determined by responses to two questions: 1) "Have you smoked at least 100 cigarettes in your life?" and 2) "Do you now smoke cigarettes?" Participants who answered yes to both questions were categorized as current smokers, participants who answered yes to the first question and no to the second were categorized as former smokers, and participants who answered no to both questions were categorized as never smokers. Geographic regions were not analyzed because NHANES is not designed to be representative at regional (or lower) levels.

Disparities were assessed by age group, sex, race/ethnicity, education, FPL, and smoking status for the total population and by race/ethnicity. Referent groups for each category had the best overall periodontal health for the category. Disparities were measured as deviations from a referent group, which was the group that had the most favorable estimate for the variables used to assess disparities during the time reported. Absolute difference was measured as the simple difference between the periodontitis prevalence for the group of interest and the referent group. The relative difference, a percentage, was calculated by dividing the absolute difference by the value in the referent category and multiplying by 100. The z test was used to assess significant differences between absolute differences from the referent group, with significance set at p<0.05. Data (using mobile examination center weights) were analyzed using statistical software to adjust for the effects of the sampling design, including the unequal probability of selection, and to determine standard errors (SEs).

Results

During 2009–2010, an estimated 47.2% of adults aged ≥30 years in the United States had periodontitis (Table 1). The prevalence of total and moderate periodontitis increased with increasing age among all adults. However, the prevalence of mild and severe periodontitis remained relatively steady at <15% across all age groups (Figure).

The prevalence of periodontitis was significantly higher in non-Hispanic blacks (58.6%) and Mexican-Americans (59.7%) compared with non-Hispanic whites (42.6%). Among all racial/ethnic groups, the prevalence of periodontitis increased with age (24.4%–70.1%), with the largest relative difference in prevalence within age groups occurring among non-Hispanic whites (range: 16.6%–68.0%). The prevalence of periodontitis was significantly higher among men (56.4%) than women (38.4%) overall, and this finding was consistent among racial/ethnic groups. By education level, periodontitis was highest among persons with less than a high school education (66.9%), and the relative difference between those with greater than a high school education and those with less education was largest in Mexican-Americans (73.8%) and smallest in non-Hispanic blacks (28.8%). The prevalence of periodontitis increased as FPL percentage decreased, with an estimate of 65.4% of persons in the poorest families (<100% FPL), representing an 85% relative increase compared with families at ≥400% FPL. The relative difference in prevalence between these categories of FPL was largest among non-Hispanic whites (82.8%) and smallest among non-Hispanic blacks (35.5%). Periodontitis was more prevalent among current smokers (64.2%) than nonsmokers (39.8%) and significantly higher among non-Hispanic black current smokers (79.1%) than non-Hispanic white (60.8%) and Mexican-American current smokers (69.1%) (Table 1).

During 2009–2010, an estimated 8.7% of the U.S. adult population had mild periodontitis. The prevalence of moderate periodontitis was 30.0% (Table 2). Prevalence of moderate periodontitis increased with age and peaked at age ≥65 years. Overall, prevalence was higher in men (33.8%) than women (26.4%) and higher among non-Hispanic black men (42.7%) than men in other racial/ethnic groups. Increasing prevalence was associated with lower education and poverty levels. Specifically, the prevalence of moderate periodontitis at the lowest levels of education and poverty were higher among non-Hispanic whites and Mexican-Americans than non-Hispanic blacks. Prevalence of moderate periodontal disease was higher among current smokers (36.5%) and former smokers (35.6%) than among nonsmokers (25.6%). However, this pattern was not consistent among non-Hispanic blacks and Mexican-Americans, among whom the highest prevalence of moderate periodontitis was among former smokers. The relative difference in prevalence between poverty levels was smallest among non-Hispanic blacks, suggesting that income had the least impact on moderate periodontitis in this racial/ethnic group. Significant absolute differences were found in moderate periodontitis among current smokers, former smokers, and nonsmokers and was significantly higher among non-Hispanic blacks.

Severe periodontitis was estimated to occur in 8.5% of U.S. adults aged ≥30 years (Table 3). Severe periodontitis was twice as common among non-Hispanic blacks (13.2%) and Mexican-Americans (13.3%) as among non-Hispanic whites (6.3%). Severe periodontitis increased with age and peaked at age 50 years among all racial/ethnic groups. Overall, severe disease was almost three times higher among men (12.5%) than women (4.2%) and approximately two times higher among non-Hispanic black men (19.3%) and Mexican-American men (18.8%) than among non-Hispanic white men (9.4%). Severe periodontitis among persons with less than a high school education was an estimated 17.3% and decreased with increasing levels of education. Among racial/ethnic groups, the smallest relative differences by level of education occurred among non-Hispanic blacks. Similarly, the prevalence of severe periodontitis increased with increasing poverty levels, with an estimated 16.3% of adults in families living at <100% FPL having severe disease. The relative difference in prevalence by poverty level (across all racial/ethnic groups) was smallest among non-Hispanic blacks, suggesting that income had the least influence on severe periodontitis in this racial/ethnic group. The prevalence of severe periodontitis was approximately two times as common among smokers at 17.7% than among former smokers (9%) and nonsmokers (5.4%) and was significantly higher among non-Hispanic blacks (24.4%) and Mexican-Americans (24.5%) than among non-Hispanic white smokers (13.9%)

Discussion

Overall, significant disparities exist in the prevalence of periodontitis by race/ethnicity, education and poverty level. These results suggest that non-Hispanic blacks and Mexican-Americans have similar prevalences of periodontitis but higher prevalences than non-Hispanic whites. In addition, the relative differences in the prevalence of total periodontitis (i.e., mild, moderate, and severe combined) among non-Hispanic blacks varied the least by poverty and education levels, possibly suggesting that poverty and education have less of an effect than other factors on the higher prevalence of periodontitis among non-Hispanic Blacks and Mexican-Americans. The highest prevalence of periodontitis was found among adults aged ≥65 years. By 2030, the number of adults aged ≥65 years in the U.S. will double to 71 million adults, or one in every five Americans (8), with significant changes in the distribution of demographic and socioeconomic groups.

Limitations

The findings in this report are subject to at least four limitations, all of which might have resulted in an underestimation of the prevalence of periodontitis cases. First, the case definitions for periodontitis used measures from four interproximal sites, and not all six of the sites were measured. Second, estimates did not include persons with gingivitis. Gingivitis is a form of periodontal disease that was not assessed in the NHANES 2009–2010 data cycle. Third, NHANES does not sample institutionalized persons such as older adults in nursing homes, which might have resulted in an underestimate for older adults. Fourth, NHANES does not collect data from third molars. This exclusion of third molars is consistent with previous NHANES data cycles; third molars are difficult to assess clinically because of their alignment in the mouth, and some are partially impacted.

Conclusion

Preventive dental care programs should be an integral part of preventive health services for all ages and should include strategies to make dental care programs accessible to all racial/ethnic groups to promote health and preserve health-related quality of life in older adults. Adults aged ≥65 years do not have dental coverage through Medicare, and approximately 70% of U.S. adults in this age group have no dental coverage (20). Management of diabetes and smoking is an important component of prevention and treatment of adult periodontitis (13). The findings in this report indicate that current smokers had a much higher prevalence of severe periodontitis; smoking is categorized as a major modifiable risk factor for periodontitis. This is consistent with the 2004 Surgeon General's Report on the Health Consequences of Smoking, which infers a causal relationship between smoking and periodontitis (21). Because the prevalence of severe periodontitis is higher among current smokers, tobacco cessation programs are a potential strategy to address disparities in periodontitis in the U.S. population (22). Two related Healthy People 2020 objectives are currently being monitored. One focuses on dental professionals providing tobacco cessation counseling in a dental setting, and another monitors consumers' self-report of tobacco cessation counseling in a dental office (9). Overall, this study demonstrates disparities in periodontitis by age, race, education, and income, and risk factors such as smoking status in the U.S. adult population. The capacity of oral health programs within state and local health agencies can be broadened to capture this subset of the population. The program activities might include efforts to 1) reduce tobacco use, particularly smoking; 2) educate persons on the benefits of regular dental care; and 3) facilitate health communication efforts to make key groups aware of effective preventive interventions.

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