The risk of first myocardial infarction (MI) significantly increased in patients with periodontitis (PD), according to results from the PAROKRANK study, published in Circulation.
A total of 805 patients (mean age: 62 ± 8 years and 81% male) were recruited from 17 Swedish hospitals from May 2010 to February 2014. Participants were all younger than 75 years of age and were hospitalized for a first MI. Exclusion criteria were prior MI or heart valve replacement.
PD was present in 43% of patients compared with 33% of controls (P<.001), and there was increased risk for MI among those with PD (odds ratio [OR]: 1.49; 95% confidence interval [CI]: 1.21-1.83). Even excluding edentulous participants (patients=12; controls=4), the OR for MI risk was 1.46 (CI: 1.19-1.80). After adjusting for confounders (smoking habits, diabetes, education, and marital status) and including edentulous participants, the risk was still significant (OR: 1.28; 95% CI: 1.03-1.60).
Both patients and controls underwent standardized dental examinations, including panoramic x-ray. Healthy periodontal status was defined as ≥80% of remaining bone, mild-moderate as 79% to 66%, and severe as <66%.
Of the potential confounders, smoking and COPD rates were higher among patients compared to controls (COPD: 4.4% vs 1.9%; P=.005). Socioeconomic status statistics revealed less education (66% vs 62%) and higher divorce rates (15% vs 10%) in the patient group. Controls had slightly more remaining teeth compared with patients (25 ± 5 vs 24 ± 6; P<.001).
Researchers acknowledged that the main limitation of the study is that it is observational. They wrote that the ideal design to provide proof of a casual relationship between PD and cardiovascular disease is “a prospective trial randomly assigning people with [PD] who are free from cardiovascular disease to dental treatment or to be left untouched and with a composite of cardiovascular death and non-fatal myocardial infarction and stroke as the primary end point.” But they acknowledged that such a study would be extremely difficult to conduct.
Nevertheless, the present study makes a strong case for the possibility of an independent relationship between PD and MI risk.
“Chewing, tooth brushing, and dental treatments transfer microorganisms from dental pockets into the blood stream causing bacteraemia and systemic inflammation,” researchers wrote. “This may provoke accelerated atherosclerotic vascular damage, aggregation of platelets, and development of thrombotic material, all of which are important for the development of acute MI.” Indeed, oral microorganism DNA has already been discovered in atherosclerotic plaques.
Ongoing studies examining diabetes and other forms of dysglycemia will hopefully discover the pathophysiological mechanisms in the connection between cardiovascular disease and PD.
Ryden L, Buhlin K, Ekstrand E, et al. Periodontitis increases the risk of a first myocardial infarction: a report from the PAROKRANK study. Circulation. 2016. doi: 10.1161/CIRCULATIONAHA.115.020324.