Lower Rate of Smoking Seen Among Cardiac Sarcoidosis Patients: Study

'Negative association' found between smoking, clinically manifest phenotype

Somi Igbene, PhD avatar

by Somi Igbene, PhD |

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Cardiac sarcoidosis may occur more frequently among people who are not current or past smokers, a study has found.

The study, “Negative association of smoking history with clinically manifest cardiac sarcoidosis: a case-control study,” was published in CJC Open.

Cardiac sarcoidosis is an inflammatory disease that occurs when clumps of white blood cells (granulomas) accumulate in the heart muscle and interfere with its electrical system, altering heart rhythm and causing heart failure.

Previous studies described specific indications that affect primarily white patients with clinically manifest cardiac sarcoidosis. In these patients, heart symptoms are usually the first and most prominent disease manifestation. Although its cause is unknown, prior research suggests it may be triggered by being exposed to environmental factors such as musty odors and insecticides.

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Researchers in Canada investigated whether smoking is associated with clinically manifest cardiac sarcoidosis. Prior studies on the disease outside the heart have been limited by a small number of participants and a broad range of disease traits.

This study was part of the ongoing Cardiac Sarcoidosis Multi-Centre Prospective Cohort Study, or CHASM-CS registry (NCT01477359), at the University of Ottawa Heart Institute wherein eligible participants underwent medical assessments including echocardiograms — which create moving images of the heart — electrocardiograms (to record the electrical activity of the heart), cardiac MRI, and CT and PET scans.

The patients were matched with controls from the Ontario Health Study, an ongoing study investigating whether lifestyle, environment, and family history raise the risk of chronic disease. All patients and controls completed a smoking history questionnaire. A total of 82 patients and 820 controls were included in the study and each patients was matched with 10 controls. The mean age of the patients was 54.7; roughly 45% were female, 96% were white.

While 28% of the patients had a smoking history (a lifetime consumption of more than 100 cigarettes), 7.3% were current smokers at the time of their diagnosis. A significantly greater percentage (47.8%)  had a smoking history in the control group, with 12.2% being smokers when they were diagnosed.

Patients with a smoking history had consumed significantly fewer cigarettes over their lifetime than the controls with a smoking history (8.31 pack-years versus 15.34 pack-years). The results also showed more severe myocardial (heart muscle) inflammation in nonsmokers than in patients who smoked.

“We found a strong and consistent negative association between smoking history and a very specific phenotype of sarcoidosis (clinically manifest cardiac sarcodoisis). Additionally, nonsmokers had more severe myocardial inflammation … compared to that of patients with a smoking history,” the researchers wrote, noting that more research was needed to better understand these relationships and if they had  “therapeutic potential.”