Wael Sabbah

Social Gradients in Oral and General Health

There are social gradients in general health and oral health. However, there have been few studies addressing whether similarities exist in the gradients in oral and general health in the same individuals. We set out to test, using data from NHANES III, whether there are social gradients in oral health, and whether they resemble the gradients in general health. Income, indicated by poverty-income ratio, and education gradients were examined in periodontal diseases, ischemic heart disease, and perceived oral/general health. Our analysis demonstrated consistent income and education gradients in all outcomes assessed. In the adjusted regression models, the probabilities of having poorer clinical and perceived health were attenuated, but remained significantly higher at each lower level of income and education for most outcomes. The results showed similar income and education gradients in oral and general health, implying commonalities of the social determinants of both oral and general health.

Association of the Metabolic Syndrome with Severe Periodontitis in a Large U.S. Population-Based Survey

CONTEXT Metabolic syndrome and periodontitis both have an increasing prevalence worldwide; however, limited information is available on their association. OBJECTIVE The objective of the study was to assess the association between periodontitis and the metabolic syndrome in a cross-sectional survey of a nationally representative sample of the noninstitutionalized civilians in the United States. DESIGN, SETTING, AND PARTICIPANTS Data analysis from the Third National Health and Nutrition Examination Survey on 13,994 men and women aged 17 yr or older who received periodontal examination were studied. MAIN OUTCOME MEASURES Association of diagnosis and extent of periodontitis (gingival bleeding, probing pocket depths) with the metabolic syndrome and its individual component conditions (central obesity, hypertriglyceridemia, low high-density lipoprotein-cholesterol, hypertension, and insulin resistance) were measured. Adjustment for age, sex, years of education, poverty to income ratio, ethnicity, general conditions, and smoking were considered. RESULTS The prevalence of the metabolic syndrome was 18% [95% confidence interval (CI) 16-19], 34% (95% CI 29-38), and 37% (95% CI 28-48) among individuals with no-mild, moderate, and severe periodontitis, respectively. After adjusting for confounders, participants aged older than 45 yr suffering from severe periodontitis were 2.31 times (95% CI 1.13-4.73) more likely to have the metabolic syndrome than unaffected individuals. Diagnosis of metabolic syndrome increased by 1.12 times (95% CI 1.07-1.18) per 10% increase in gingival bleeding and 1.13 times (95% CI 1.03-1.24) per 10% increase in the proportion of periodontal pockets. CONCLUSIONS Severe periodontitis is associated with metabolic syndrome in middle-aged individuals. Further studies are required to test whether improvements in oral health lead to reductions in cardiometabolic traits and the risk of metabolic syndrome or vice versa.

The role of health-related behaviors in the socioeconomic disparities in oral health

This study aimed to examine the socioeconomic disparities in health-related behaviors and to assess if behaviors eliminate socioeconomic disparities in oral health in a nationally representative sample of adult Americans. Data are from the US Third National Health and Nutrition Examination Survey (1988-1994). Behaviors were indicated by smoking, dental visits, frequency of eating fresh fruits and vegetables and extent of calculus, used as a marker for oral hygiene. Oral health outcomes were gingival bleeding, loss of periodontal attachment, tooth loss and perceived oral health. Education and income indicated socioeconomic position. Sex, age, ethnicity, dental insurance and diabetes were adjusted for in the regression analysis. Regression analysis was used to assess socioeconomic disparities in behaviors. Regression models adjusting and not adjusting for behaviors were compared to assess the change in socioeconomic disparities in oral health. The results showed clear socioeconomic disparities in all behaviors. After adjusting for behaviors, the association between oral health and socioeconomic indicators attenuated but did not disappear. These findings imply that improvement in health-related behaviors may lessen, but not eliminate socioeconomic disparities in oral health, and suggest the presence of more complex determinants of these disparities which should be addressed by oral health preventive policies.

Effects of allostatic load on the social gradient in ischaemic heart disease and periodontal disease: evidence from the Third National Health and Nutrition Examination Survey

Introduction: Psychosocial stress and allostatic load have been postulated as a mechanism explaining socioeconomic inequalities in general and oral health. This study tested whether markers of allostatic load are associated with both ischaemic heart disease and periodontal disease and whether they affect education and income gradients for both conditions. Methods: Data are from the Third National Health and Nutrition Examination Survey, conducted in the United States from 1988 to 1994. Ischaemic heart disease was determined by the presence of angina or diagnosis of heart attack. Four variables were used for periodontal disease. Individual and aggregate markers of allostatic load were used. Results: Allostatic load (both aggregate and most individual markers) was associated with higher probabilities of all examined health outcomes. Adjusting for markers of allostatic load attenuated education and income gradients in both ischaemic heart disease and periodontal disease. The relationship between socioeconomic position and the examined health outcomes remained significant. Conclusion: Indicators of allostatic load were associated with ischaemic heart disease and periodontal disease and had a mediating effect partly explaining the social gradients in both diseases. The results suggest a possible common stress pathway linking socioeconomic position to both conditions.

Oral health and cognitive function in the Third National Health and Nutrition Examination Survey (NHANES III).

Objectives: To investigate the association between oral health and cognitive function in early-, mid-, and late-adult life. Methods: A secondary analysis was carried out of a large, well-characterized community sample (NHANES III). Analyzed variables included three measures of oral health (gingival bleeding, loss of periodontal attachment, loss of teeth) and three measures of cognitive function: the Symbol Digit Substitution Test (SDST), the Serial Digit Learning Test (SDLT) (both in 5138 participants aged 20–59 years), and a Story Recall test (in 1555 participants aged ≥70 years). Other covariates in linear regression models included age, gender, ethnicity, education and poverty, and cardiovascular risk factors. Results: Worse scores on all three measures of oral health status were significantly associated with poorer performance on all three measures of cognitive function after adjustment for age. Education was an important confounding factor. However, after full adjustment for all other covariates, gingival bleeding (%) and loss of periodontal attachment (%) remained associated with relative impairment on SDST score (B coefficients both = 0.003), and gingival bleeding was associated with relative impairment on SDLT (B = 0.017). No effect modification by age was observed. Conclusions: Poor oral health is associated with worse cognitive function throughout adult life. This may, in part, be accounted for by early life education and social status. However, the possibility of direct causal pathways requires further investigation. NHANES III = Third National Health and Nutrition Examination Survey; SDST = Symbol Digit Substitution Test; SDLT = Serial Digit Learning Test.

Five-Year Incidence of Periodontal Disease Is Related to Body Mass Index

Numerous cross-sectional epidemiological studies suggest that obesity is associated with periodontal disease. This longitudinal study tested whether body mass index (BMI) was related to the development of periodontal disease in a sample of employed Japanese participants. Data are from the statutory medical checkups routinely collected for employees in and around Nagoya, Japan. The authors tested the relationship between BMI at baseline and the 5-year incidence of periodontal disease in a sample of 2787 males and 803 females. The hazard ratios for developing periodontal disease after 5 years were 1.30 (P < .001) and 1.44 (P = .072) in men and 1.70 (P < .01) and 3.24 (P < .05) in women for those with BMIs of 25-30 and ≥ 30, respectively, compared to those with BMI < 22, after adjusting for age, smoking status, and clinical history of diabetes mellitus. These findings demonstrate a dose-response relationship between BMI and the development of periodontal disease in a population of Japanese individuals.

Using Universal Patterns of Caries for Planning and Evaluating Dental Care

There are universal patterns of caries, in terms of prevalence, incidence, frequency distribution and rates of progression, in permanent teeth that can be considered working rules that can be applied when planning dental care. The universal patterns are: (1) caries levels follow trend lines; therefore, knowing the caries level at one age can be used to predict the levels at later ages in that cohort by looking at the trend line for that cohort; (2) the distribution of dental caries of a population exhibits the following characteristics: as the mean DMFT increases, the percentage of caries-free individuals falls and the caries distribution widens; this changing relationship between the mean DMFT and prevalence is not limited to a subgroup of the population who already have had some caries experience; (3) there is a specific mathematical relationship between the mean DMFT and mean DMFS; (4) there is a hierarchy of caries susceptibility by tooth type and sites on teeth; for a given DMFT or DMFS, there is a specific intra-oral pattern of caries by tooth type; (5) changes in mean DMFT scores for individuals and groups are not linear, but ‘stepped’; there are groupings of teeth and tooth sites that may have similar ‘resistance’ to caries; (6) as the mean DMFT declines, the posteruptive time for initiation of caries increases and the progression rate of caries through enamel decreases. This is true regardless of the presence of fluoride. Any improvement in dental health will cause this effect.

Relationship between Periodontal Status and Levels of Glycated Hemoglobin

The objective of this study was to assess whether there is a bi-directional relationship between periodontal status and diabetes. Study 1 included 5,856 people without periodontal pockets of ≥ 4 mm at baseline. Relative risk was estimated for the 5-year incidence of periodontal pockets of ≥ 4 mm (CPI scores 3 and 4, with the CPI probe), in individuals with glycated hemoglobin (HbA1c) levels of ≥ 6.5% at baseline. Study 2 included 6,125 people with HbA1c < 6.5% at baseline. The relative risk was assessed for elevation of HbA1c levels in 5 years, with baseline periodontal status, assessed by CPI. Relative risk of developing a periodontal pocket was 1.17 (p = 0.038) times greater in those with HbA1c of ≥ 6.5% at baseline, adjusted for body mass index (BMI), smoking status, sex, and age. Relative risks for having HbA1c ≥ 6.5% at 5-year follow-up in groups with periodontal pockets of 4 to 5 mm and ≥ 6 mm at baseline were 2.47 (p = 0.122) and 3.45 (p = 0.037), respectively, adjusted for BMI, alcohol consumption, smoking status, sex, and age. The risk of developing periodontal disease was associated with levels of HbA1c, and the risk of elevations of HbA1c was associated with developing periodontal pockets of more than 4 mm.

Is periodontal inflammation associated with raised blood pressure? Evidence from a National US survey.

There is incomplete and inconclusive evidence for the association between periodontal disease markers and arterial blood pressure, particularly from large national epidemiological studies. This study assessed the relationship between different markers of periodontal inflammation and disease with arterial blood pressure in people aged 17 years and over in USA. We analysed data from the Third National Health and Nutrition Examination Survey on 6617 men and 7377 women who received a periodontal examination. Blood pressure was analysed in both a continuous format and a binary variable for case definition of hypertension. Periodontal disease markers (extent of gingival bleeding, pocket depth, and loss of attachment, and a case definition of periodontitis) were associated on the arterial blood pressure outcomes through a series of regression models, incrementally adjusting for confounders (demographic, inflammation markers, chronic conditions, smoking, BMI, socio-economic status). All periodontal measures had significant crude associations with SBP and hypertension. Gingival bleeding, a marker of current periodontal inflammation, was the only measure consistently and significantly associated with raised SBP and an increased odds of hypertension in the US adult population throughout the adjustment process. For a 10% greater extent of gingival bleeding, the average SBP was higher by 0.5 (0.3, 0.6) mmHg in the fully adjusted model. By referring to the general population and the whole distribution of blood pressure, not only to those at higher risk for hypertension, this association might have some important implications for clinical practice and public health strategies.

Income, income inequality, dental caries and dental care levels: an ecological study in rich countries

Research has shown that beyond a certain level of absolute income, there is a weak relationship between income and population health. On the other hand, relative income or income inequality is more strongly related to health than absolute income in rich countries. The objective of this study was to assess the relationships of income and income inequality with dental caries and dental care levels in 35- to 44-year-old adults among rich countries. Income was assessed by gross domestic product and gross national income, income inequality by Gini coefficient and the ratio between the income of the richest and poorest 20% of the population, dental caries by DMFT and dental care levels by the care, restorative and treatment indices. Pearson and partial correlation were used to examine the relationships between income, income inequality, caries experience and dental care. Income measures were not related to either dental caries or dental care levels. However, income inequality measures were inversely and significantly related to number of filled teeth, DMFT, care index and restorative index, but not to number of decayed or missing teeth. It is concluded that DMFT scores were higher in more equal countries and may be explained by greater levels of restorative care in those countries.