Written by Marcia J. Egles, MD. This study is an updated comprehensive analysis of cigarette smoking and its association with cardiovascular disease.
More than fifty years have passed since the United States’ surgeon general warned of the health hazards of cigarette smoking (2). A recent large, multi-ethnic study is in keeping with those warnings, finding that cigarette smoking is still an important determinant of cardiovascular disease.(1) Despite the potential for prevention, tobacco has killed more than 20 million people prematurely since the first Surgeon General’s report in 1964 (2). “Smoking remains the nation’s most important health hazard” (3).
This updated study is a comprehensive analysis of cigarette smoking and prospective cardiovascular events from the Multiethnic Study of Atherosclerosis (MESA)(3). A total of 6814 adults free of cardiovascular disease and coronary heart disease, aged 45-84, were followed for an average of 10.2 years. The participants’ smoking histories were obtained by self-reports and confirmed by the testing of their urine for cotinine, an indicator of tobacco exposure. The men and women were identified as 3218 persons who had never smoked, 2607 former smokers, and 971 current smokers. Four ethnic groups (Caucasian, African-American, Chinese-American, and Hispanic) from six American communities (Baltimore, Chicago, Los Angeles, New York city, St. Paul, and Forsyth County, North Carolina) took part in the study.
Significantly poorer statistics for adverse events such as death, stroke and heart attacks were found among the smokers as compared to the nonsmokers. For example, compared to those who never smoked, adjusted hazard ratios in current smokers were 1.7 (95 % confidence interval, 1.3-2.2) for overall cardiovascular disease events as well as 1.7 (95%c.i. = 1.2-2.4) for myocardial infarctions and death from coronary disease. The associations between smoking and cardiovascular events were irrespective of race or gender.
The study confirmed a dose-response relationship between smoking and cardiovascular disease events. Among current smokers, hazard ratios were higher in the 4th versus 1st quartile of pack years. All-cause cardiovascular incidence rates were 8.1 events per 1000 person years for the 1st quartile of pack years versus 18.9 events per 1000 person years for the 4th quartile ( p less than 0.001).
The statistics for true former smokers were encouraging. The former smokers in this study had a very long average time of smoking cessation with an average cessation interval of 22 years. For these former smokers, the results were similar to those who had never smoked.
Both subclinical atherosclerosis and inflammation are thought to be key components in the development of smoking-induced cardiovascular disease. Calcium deposits in the coronary arteries can appear on CT scan in advance of a person’s clinical manifestations of coronary disease. . High sensitivity C-reactive protein serum levels are a marker for systemic inflammation, as well as for cardiovascular inflammation. In this study, both coronary arterial calcifications on cardiac CT scans and high sensitivity C-reactive protein serum levels were shown to identify current smokers who were at higher risk for cardiovascular events(1).
Overall, the current study showed that cigarette smoking is associated with hazardous cardiovascular outcomes irrespective of gender or ethnicity. Both current smoking as well as cumulative exposure to cigarette smoke remain important determinants of cardiovascular disease.
Source: McEvoy, John W., et al. “Cigarette Smoking and Cardiovascular Events.” Arteriosclerosis, thrombosis, and vascular biology (2015): ATVBAHA-114.
Posted October 28, 2015.
Marcia Egles, MD, graduated from Vanderbilt University School of Medicine in 1986. She completed her residency in Internal Medicine at St. Louis University Hospital. Dr. Egles is certified in Internal Medicine and is a member of the American College of Physicians. She resides in Avon, IN with her husband and two sons.
References:
- McEvoy, John W. et al Cigarette Smoking and Cardiovascular Events, Role of Inflammation and Subclinical Atherosclerosis From the Multiethnic Study of Atherosclerosis, Arterioscler Thromb Vasc Biol. 2015: 35:700-709. DOI: 10.1161/ATVBAHA.114.304562.
- U.S. Department of Health and Human Services. The Health Consequences of Smoking: 50 Years of Progress. A Report of the Surgeon General. Atlanta, GA: U.S. Department of Health and Human Services, Centers for Disease Control and Prevention, National Center for Chronic Disease Prevention and Health Promotion, Office on Smoking and Health, 2014.
- Schroeder SA. New evidence that cigarette smoking remains the most important health hazard. N Engl J Med. 2013: 368: 389-390. doi: 10.1056/NEJMe1213751.
- Bild DE, Bluemke DA, Burke GL et al. Multi-ethnic study of atherosclerosis: objectives and design. American journal of epidemiology 2002;156:871-81.
