Coronary heart disease patients may not understand the risks second-hand smoke have on their health. While 89.7 percent of patients in a study published online Nov. 11 in JAMA: Internal Medicine stated they understood that second-hand tobacco smoke was harmful, only about half realized the relevance to their own lives.

Sandra J. Japuntich, PhD, of the National Center for Posttraumatic Stress Disorder at the Veterans Affairs Boston Healthcare System, and colleagues enrolled 214 non-smoking patients hospitalized for coronary heart disease. Recruitment occurred between May 25, 2010 and Jan. 27, 2011 at the Massachusetts General Hospital in Boston.

Patients were interviewed about their second-hand smoke exposure, home and car rules about smoking, beliefs about exposure risks and whether or not they had spoken with healthcare professionals previously regarding second-hand smoke exposure. Saliva samples were also taken to assay for cotinine, a nicotine metabolite and an indicator of recent exposure.

Twenty-two percent of patients reported second-hand tobacco smoke exposure 30 days prior to hospital admission; 15.4 percent of patients had been exposed within seven days before admission. While two-thirds of patients had a household smoking ban and nearly three-fourths had a car smoking ban, 13.6 percent lived with a smoker, whether a spouse or adult child.

Saliva analysis revealed 15 out of 184 samples had cotinine levels of 0.20 ng/ml or more. More sensitive analysis on 72 samples revealed detectable cotinine in 40.3 percent.

When asked, 17.3 percent of patients remembered being queried by hospital staff about second-hand smoke exposure since admission and 9.8 percent had been asked if they lived with a smoker. According to 1.4 percent of patients, hospital staff had reminded them to keep their car and home smoke free.

Japuntich et al noted that half of patients were not worried about their own second-hand smoke exposure and either disagreed or did not know that second-hand smoke exposure increased heart-attack risk in non-smokers.

The research team recommended these findings as evidence of the need to more effectively address second-hand smoke exposure with in- and outpatient cardiology patients. “Hospitals and health care systems are missing an opportunity to identify and intervene in this major modifiable cardiovascular risk factor,” Japuntich et al wrote.