Examination of the Relationship between Oral Health and Arterial Sclerosis without Genetic Confounding through the Study of Older Japanese Twins

<div><p>Objective</p><p>Although researchers have recently demonstrated a relationship between oral health and arterial sclerosis, the genetic contribution to this relationship has been ignored even though genetic factors are expected to have some effect on various diseases. The aim of this study was to evaluate oral health as a significant risk factor related to arterial sclerosis after eliminating genetic confounding through study of older Japanese twins.</p><p>Subjects and Methods</p><p>Medical and dental surveys were conducted individually for 106 Japanese twin pairs over the age of 50 years. Maximal carotid intima-media thickness (IMT-Cmax) was measured as a surrogate marker of arterial sclerosis. IMT-Cmax > 1.0 mm was diagnosed as arterial sclerosis. All of the twins were examined for the number of remaining teeth, masticatory performance, and periodontal status. We evaluated each measurement related with IMT-Cmax and arterial sclerosis using generalized estimating equations analysis adjusted for potential risk factors. For non-smoking monozygotic twins, a regression analysis using a “between within” model was conducted to evaluate the relationship between IMT-Cmax and the number of teeth as the environmental factor controlling genetic and familial confounding.</p><p>Results</p><p>We examined 91 monozygotic and 15 dizygotic twin pairs (males: 42, females: 64) with a mean (± standard deviation) age of 67.4 ± 10.0 years. Out of all of the oral health-related measurements collected, only the number of teeth was significantly related to arterial sclerosis (odds ratio: 0.72, 95% confidence interval: 0.52-0.99 per five teeth). Regression analysis showed a significant association between the IMT-Cmax and the number of teeth as an environmental factor (<i>p</i> = 0.037).</p><p>Conclusions</p><p>Analysis of monozygotic twins older than 50 years of age showed that having fewer teeth could be a significant environmental factor related to arterial sclerosis, even after controlling for genetic and familial confounding.</p></div

Association between the number of teeth and IMT-Cmax in regression analysis using the “between within” model.

<p>Association between the number of teeth and IMT-Cmax in regression analysis using the “between within” model.</p

Relationship between atherosclerosis and occlusal support of natural teeth with mediating effect of atheroprotective nutrients: From the SONIC study

<div><p>Whereas most of studies investigating relationship between oral health and atherosclerosis have focused on periodontitis, very few of them were examined about occlusal status of natural teeth which possibly influence dietary habit. The primary aim of this cross-sectional study was to investigate the association between the occlusal support of posterior teeth and the prevalence of atherosclerosis in community-dwelling septuagenarians. Also, the second aim was to test the hypothesis that the intake of key nutrients for atherosclerosis prevention would have a mediating effect on the relationship between the occlusal status and atherosclerosis. The study population included 468 community-dwelling dentate persons aged 69–71 years recruited from the local residential registration in Japan. Participants were divided into three groups, according to the number of occlusal support zones (OSZ) in the posterior area: Complete (four OSZ), Moderate (three or two OSZ), and Collapsed (one or no OSZ). Dietary intakes were assessed using a brief-type self-administered diet history questionnaire. Atherosclerosis was defined as carotid intima-media thickness ≧1.10 mm by using carotid ultrasonography test. The logistic or linear regression model was used in multivariate analysis to assess relationship between occlusal status and atherosclerosis, and the mediating effect of key nutrients within the relationship. Multivariable analysis showed a significant association between occlusal status and atherosclerosis (odds ratio for Collapsed group to Complete group: 1.87; 95% CI: 1.45–2.41), independent of periodontal status (odds ratio: 2.01, 95%CI: 1.46–2.78). Fish and shellfish, vitamin B6 and n-3PUFAs were significantly related to both of occlusal status and atherosclerosis, and also was indicated a mediating effect on the association between occlusal status and atherosclerosis. This study implied that, within the limitation of the cross-sectional study design, the reduced posterior occlusion was related to the increased prevalence of atherosclerosis via the decline of key dietary intakes among Japanese community-dwelling dentate individuals.</p></div

Demographic and clinical characteristics of the group A by prevalence of atherosclerosis.

<p>Demographic and clinical characteristics of the group A by prevalence of atherosclerosis.</p

Odds ratio of occlusal status towards atherosclerosis assessing the effect of fish and shellfish, vitamin B6 and n-3PUFAs.

<p>CI: Confidence Interval, OR: Odds Ratio, n-3PUFAs: n-3 polyunsaturated fatty acid, Model*: adjusting for periodontal disease, gender, region of residence, smoking habits, drinking habits, education level, diabetes mellitus, hypertension, dyslipidemia, and hyperuricemia., Model**: Model* + (Fish & Shellfish), Model***: Model* + (Vitamin B6), Model****: Model* + (n-3PUFAs).</p

Demographic and clinical characteristics of the group B by prevalence of atherosclerosis.

<p>Demographic and clinical characteristics of the group B by prevalence of atherosclerosis.</p

Relationship of each key food or nutrient to atherosclerosis and to occlusal support, adjusted for covariates.

<p>Relationship of each key food or nutrient to atherosclerosis and to occlusal support, adjusted for covariates.</p

Unadjusted association between key food or nutrient intakes and occlusal support.

<p>Unadjusted association between key food or nutrient intakes and occlusal support.</p

Odds ratios of main variables with adjustment for periodontal disease.

<p>Odds ratios of main variables with adjustment for periodontal disease.</p

Occlusal force is correlated with cognitive function directly as well as indirectly via food intake in community-dwelling older Japanese: From the SONIC study

<div><p>Background</p><p>Growing evidence suggests that oral health may be an important factor associated with cognitive function in aged populations. However, many previous studies on this topic used insensitive oral indicators or did not include certain essential covariates. Thus, we examined the association between occlusal force and cognitive function in a large sample of older adults, controlling for dietary intake, vascular risk factors, inflammatory biomarkers, depression, and genetic factors.</p><p>Methods</p><p>In this cross-sectional study of older community-dwelling Japanese adults, we examined data collected from 994 persons aged 70 years and 968 persons aged 80 years. Cognitive function was measured using the Japanese version of the Montreal Cognitive Assessment (MoCA-J). Oral status and function were evaluated according to the number of remaining teeth, periodontal pocket depth, and maximal occlusal force. Associations between MoCA-J scores and occlusal force were investigated via bivariate and multivariate analyses.</p><p>Results</p><p>Education level, financial status, depression score, and intake of green and yellow vegetables, as well as number of teeth and occlusal force, were significantly correlated with MoCA-J scores in both age groups. Among individuals aged 80 years, CRP and periodontal status were weakly but significantly associated with MoCA-J score. After controlling for all significant variables via bivariate analyses, the correlation between maximal occlusal force and cognitive function persisted. A path analysis confirmed the hypothesis that cognitive function is associated with occlusal force directly as well as indirectly via food intake.</p><p>Conclusions</p><p>After controlling for possible factors, maximal occlusal force was positively associated with cognitive function directly as well as indirectly through dietary intake.</p></div