Periodontitis Seen Related to Elevated Risk of First MI
January 20, 2016
STOCKHOLM, SWEDEN — Patients who had a first MI were more likely to have periodontitis than matched controls, in a large, case-control study. Specifically, 43% of MI patients vs. 33% of matched controls had mild to severe periodontitis in the Periodontitis and Its Relation to Coronary Artery Disease (PAROKRANK) study. After researchers controlled for smoking, diabetes, education, and marital status, individuals with periodontitis had a 28% increased risk of MI.
These findings, by Dr Lars Rydén (Karolinska University Hospital, Stockholm, Sweden), senior author Professor Björn Klinge (Malmö University, Sweden), and colleagues, were published January 13, 2016 in Circulation.
"PAROKRANK does therefore provide further and much stronger evidence favoring a causal relation between periodontitis and MI," Rydén told heartwire from Medscape. "Still, a case-control study cannot be taken as firm proof of this," he cautioned. Likewise, in an accompanying editorial, Dr Ralph Stewart (Auckland City Hospital, New Zealand) and Dr Malcolm West (University of Queensland, Brisbane, Australia) warn that the current study "adds to the strong evidence for an association between periodontitis and myocardial infarction but does not prove causation."
Rydén advises that "a patient with a cardiovascular problem may very well have periodontal disease, and if this is suspected, referral to a dentist for check-up of the oral condition is recommended." On the other hand, "patients with periodontitis should be asked about any other risk factors and signs of cardiovascular disease."
Does Gum Disease cause Heart Disease?
About half of all adults over age 30 in the US have periodontitis, a chronic inflammatory disease, Stewart and West write. And in the past 25 years, more than 50 prospective cohort and case-control studies have reported that periodontitis is associated with atherosclerotic vascular disease, but they have not shown cause and effect. "If causal, these associations would be of great importance, because of the potential that preventing or treating periodontal disease could reduce the risk of major adverse cardiovascular events," they note.
However, the previous trials were small or had incomplete information about potential confounders or lacked an objective measure of periodontitis, Rydén and colleagues write. Thus, in a 2012 statement, the AHA warned that there is no solid evidence that periodontitis causes specific atherosclerotic vascular disease events.
To investigate this, PAROKRANK enrolled 805 patients under age 75 who had a first MI and were treated in one of 17 Swedish hospitals from 2010 to 2014. Then, from a national registry, the researchers randomly selected and enrolled 805 controls without MI, who were matched with patients based on their age, gender, and postal code (a surrogate for socioeconomic status).
Study participants had a physical examination and blood tests, and they replied to questionnaires about medical history, family history, and depression.
Participants also had a dental exam with a panoramic x-ray. Based on this exam, they were classed as having no, mild to moderate, or severe periodontitis—if they had >80%, 79% to 66%, or <66% of alveolar bone remaining, respectively. The patients had a mean age of 62 and 81% were males.
At baseline, more patients than controls had known or newly detected diabetes (19% vs 13%, P<0.002), were current or former smokers (62% vs 57%), had a low education level (66% vs 62%), or were divorced (15% vs 10%). After adjustment for these confounders, patients with periodontitis still had an increased risk of MI (odds ratio 1.28; 95% CI 1.03–1.60).
Smoking and diabetes are the main risk factors for periodontitis, Rydén noted. The message to patients is "quit smoking if you are eager to keep your teeth and to improve your heart health!" he stressed.
In addition, individuals can lower their risk of periodontitis by "careful tooth-brushing and interdental cleaning and regular supportive dental professional checkups and treatment." Gingivitis can progress to severe periodontitis, so patients need to take special care of infected gums. A tooth implant to replace a missing one can improve quality of life, "but oral hygiene and professional checkups are just as important, since patients may develop peri-implantitis, which is similar to periodontitis," according to Rydén.
The researchers are extending this work to see whether mental health, stress, exhaustion, dental issues, diet, and other factors may help explain the association between periodontitis and MI.
The PAROKRANK study was supported by grants from AFA Insurance, the Swedish Heart-Lung Foundation, the Swedish Research Council, the Swedish Society of Medicine, the Stockholm County Council, and the Baltic Child Foundation. The authors and editorialists have no relevant financial relationships.