Representatives of the Johns Hopkins Bloomberg School of Public Health studied the health status of smokers. It was possible to find out that heart failure develops twice as often as in those who never smoke. This higher rate was observed in the two main heart failure subtypes and confirms that cigarette smoking is a significant risk factor for both subtypes.
The study is considered one of the first to evaluate the association of smoking with both subtypes of heart failure: decreased ejection fraction and preserved ejection fraction.
For their study, the researchers analyzed data from a multi-year study of almost 9,500 people in four US locations. The study found that participants who quit smoking maintained a significantly increased risk of developing any type of heart failure for decades after quitting smoking.
The results of the study were published June 6 in the Journal of the American College of Cardiology.
“These results highlight the importance of smoking prevention in the first place, especially among children and young adults,” says senior study author Kunihiro Matsushita, MD, PhD, assistant professor of epidemiology at the Bloomberg School. “We hope our results will encourage current smokers to quit sooner rather than later, as the harms of smoking can persist for up to three decades.”
Heart failure is a progressive condition in which the heart is unable to pump enough blood to meet the body’s needs. It is one of the most common causes of disability and death in developed countries, with more than 6 million adults living with heart failure in the US alone, according to the latest figures from the Centers for Disease Control and Prevention. In addition to cigarette smoking, risk factors for heart failure include obesity, hypertension, diabetes, coronary heart disease, and older age.
There are two types of heart failure: reduced ejection fraction and preserved ejection fraction. In heart failure with reduced ejection fraction, the left ventricle—the heart’s main pump—cannot contract enough to force blood out. Heart failure with reduced ejection fraction is more closely associated with coronary artery disease. Treatment includes several drugs that improve the prognosis.
In heart failure with preserved ejection fraction, the left ventricle does not have enough time to relax after contraction. The treatment of heart failure with preserved ejection fraction is very limited, making its prevention critical. At the same time, the risk factors for this disease are less clear. Some previous studies have linked smoking to an increased risk of heart failure with preserved ejection fraction, while others have not.
Matsushita and colleagues evaluated the medical records of participants in the Atherosclerosis Risk In Communities (ARIC) study. The ARIC study, which began in 1987, includes middle-aged and older adults from the United States, who are heavily dominated by blacks. The analysis of the new study included data from four communities in Maryland, North Carolina, Minnesota, and Mississippi and focused on 9,345 ARIC participants aged 61 to 81 who had sufficient records and no diagnosis of heart failure as of early 2005.
During a mean follow-up period of 13 years, 1215 cases of heart failure were reported in the study, including 492 cases with reduced ejection fraction and 555 cases with preserved ejection fraction. The investigators’ analysis showed that smokers in the group were diagnosed with two subtypes of heart failure at about the same rate as never-smokers – 2.28 times more likely with preserved ejection fraction and 2.16 times more likely with reduced ejection fraction ejection.
The association with smoking also showed a dose-response relationship – more cigarettes per day and more years of smoking were associated with a higher risk of heart failure. Similarly, quitting smoking resulted in a reduced risk of heart failure that increased over time. Overall, ex-smokers were 31% and 36% more likely to retain ejection fraction and decrease ejection fraction, respectively, compared to never-smokers.
When the researchers divided ex-smokers by the number of years since quitting, they found that their overall risk of heart failure remained significantly higher than that of never-smokers, except for the group who had not smoked for 30 years or more.
“This reinforces the notion that smoking casts a long shadow on heart health,” says Matsushita.