Periodontitis, carotid calcifications and future cardiovascular diseases in older individuals

Background. Periodontitis is a chronic inflammatory disease with a microbiological etiology affecting the supporting tissues of the tooth. The disease affects approximately 50% of the adult population. The prevalence of periodontitis increases with age. The complex bacterial infection, as well as an exaggerated host inflammatory reaction, may trigger subclinical atherosclerosis. Aims. The overall aim of the present thesis was to study the associations between periodontitis, cardiovascular diseases and mortality. The specific aims were: I) to evaluate the use and value of panoramic radiographs in assessing carotid calcifications in relation to other used methods (gold standards) and to assess the literature on carotid calcifications defined from panoramic radiographs and concurrent diagnosis of stroke and periodontitis, II) to evaluate if periodontitis is associated with the presence of carotid arterial calcifications diagnosed on panoramic radiographs in an elderly population, III) to assess if carotid calcifications detected on panoramic radiographs are associated with future events of stroke, and/or ischemic heart diseases over 10–13 years in individuals between 60 and 96 years, IV) to assess if individuals ≥ 60 years of age with periodontitis are more likely to develop stroke or ischemic heart diseases or are at higher risk of death over a period of 17 years. Methods: A literature review based on peer-reviewed studies was performed evaluating the use of panoramic radiographs in assessing carotid calcifications compared to other methods. In study II, III, IV older individuals, 60 years and older participating in the Swedish National Study of Aging and Care (SNAC) were included in the studies. A dental hygienist performed a dental clinical and radiographic examination. Probing depths (PD) and bleeding on probing (BOP) was registered. From radiographic panoramic images, the distances between the alveolar bone level and the cement enamel junction (CEJ) were measured. In study II, a diagnosis of periodontitis was declared, using a composite definition; if a distance between the alveolar bone level and the CEJ ≥5 mm on panoramic radiographs at >10% of sites and PD ≥5 mm at one or more teeth and with BOP >20% of teeth. In study IV, an indicator of a history of periodontal disease was declared if a distance between the alveolar bone level and the CEJ ≥5 mm on panoramic radiographs at ≥30% of sites. Evidence of a radiopaque nodular mass in the intervertebral space at or below the vertebrae C3-C4 was identified as carotid calcification. In addition, a medical research team performed the medical examinations, and a medical doctor (JB) reviewed all medical records for information about events of stroke and ischemic heart diseases. Stroke and ischemic heart diseases were registered according to the ICD 10 codes: ICD 60-69 for stroke and ICD: 20-25 for ischemic heart diseases. Study I was a review of the literature, in study II, a cross-sectional study design was employed. In studies III and IV, a longitudinal prospective study design was used. Results: On the use of panoramic radiographs in assessing carotid calcifications in relation to other used methods, the sensitivity and specificity varied between studies published. Furthermore, only a small number of studies were found concerning carotid calcifications and stroke. These studies were primarily retrospective. Four studies were found on the association between periodontitis and carotid calcification. Study II identified that older individuals with periodontitis had a significantly higher prevalence of carotid calcifications than individuals who did not have a diagnosis of periodontitis. In study III, a significant association was found between carotid calcifications on panoramic radiographs and 13- year incidence of stroke using a logistic regression analysis adjusted for confounders (BMI, diabetes type 2, hypertension) in the 60-72 years. A statistically significant crude association between radiographic evidence of carotid calcifications and incidence of ischemic heart diseases was found in individuals between 60-72 years. Such an association was, however, not identified among individuals older than 72 years. In study IV, Cox regression analysis was used, adjusted for confounders (age group, BMI >30, diabetes type 2, gender, hypertension, history of AMI, history of stroke, periodontitis, smoking) and with a definition of periodontitis as having a distance between the alveolar bone level and the CEJ ≥5 mm in panoramic radiographs at ≥ 30% of sites. Periodontitis increased the risk for ischemic heart diseases in all individuals, in women and in the 78-96 years age group (OO). Associations between periodontitis, and mortality were found in all individuals, in men and in the 60-72 years age group (YO) in the long term follow-up. Conclusions: 1. 1. Study I identified that there are studies which have assessed the value of panoramic radiographs in relation to other used methods (gold standards). The sensitivity and the specificity varied, with the specificity being more often higher. Few studies have considered the relationship between radiographic evidence of carotid calcifications and stroke. Four studies identified a relationship between a diagnosis of periodontitis and carotid calcifications on panoramic radiographs. 2. Study II identified a significant association between periodontitis and carotid calcification in individuals 60-96 years. 3. Study III identified that signs of carotid calcifications assessed from panoramic radiographs from the 60-96-year-old individuals were consistent with an incident of stroke and/or ischemic heart diseases over 13 years follow-up. 4. Study IV identified that periodontitis was associated with future ischemic heart diseases in all individuals, in women and in the 78- 96 years age group. Periodontitis was associated with mortality in all indviduals, in men and in the 60-72 years age group