Abstract and Introduction
Unhealthy lifestyle habits are a major contributor to coronary artery disease. The purpose of the present study was to investigate the associations of smoking, weight maintenance, physical activity, and diet with coronary calcium, cardiovascular events, and mortality. US participants who were 44–84 years of age (n = 6,229) were followed in the Multi-Ethnic Study of Atherosclerosis from 2000 to 2010. A lifestyle score ranging from 0 to 4 was created using diet, exercise, body mass index, and smoking status. Coronary calcium was measured at baseline and a mean of 3.1 (standard deviation, 1.3) years later to assess calcium progression. Participants who experienced coronary events or died were followed for a median of 7.6 (standard deviation, 1.5) years. Participants with lifestyle scores of 1, 2, 3, and 4 were found to have mean adjusted annual calcium progressions that were 3.5 (95% confidence interval (CI): 0.0, 7.0), 4.2 (95% CI: 0.6, 7.9), 6.8 (95% CI: 2.0, 11.5), and 11.1 (95% CI: 2.2, 20.1) points per year slower, respectively, relative to the reference group (P = 0.003). Unadjusted hazard ratios for death by lifestyle score were as follows: for a score of 1, the hazard ratio was 0.79 (95% CI: 0.61, 1.03); for a score of 2, the hazard ratio was 0.61 (95% CI: 0.46, 0.81); for a score of 3, the hazard ratio was 0.49 (95% CI: 0.32, 0.75); and for a score of 4, the hazard ratio was 0.19 (95% CI: 0.05, 0.75) (P < 0.001 by log-rank test). In conclusion, a combination of regular exercise, healthy diet, smoking avoidance, and weight maintenance was associated with lower coronary calcium incidence, slower calcium progression, and lower all-cause mortality over 7.6 years.
Coronary heart disease (CHD) remains the leading cause of death worldwide. There has been much attention paid to the role of lifestyle modification in CHD risk reduction. As part of their 2020 Impact Goals, the American Heart Association (AHA) developed a model of ideal cardiovascular health that included avoiding smoking, maintaining a body mass index (BMI, measured as weight (kg)/height (m)2) less than 25, being physically active, and adhering to a healthy diet. A recent study from the National Health and Nutrition Examination Survey (NHANES) showed an inverse correlation between the AHA's ideal cardiovascular health parameters and all-cause mortality rates. Another study of over 80,000 women showed that individuals who did not smoke, maintained a BMI of less than 25, exercised for 30 minutes/day, and consumed a Mediterranean-style diet had a 92% lower risk of sudden cardiac death.
To build a causal argument in epidemiologic studies, it is critical to show that these behaviors are associated with intermediate measures of disease, as well as with hard endpoints. The purpose of the present study was to investigate the associations of healthy diet, regular exercise, smoking avoidance, and normal weight maintenance with coronary artery calcium (CAC) incidence, CAC progression, CHD events, and all-cause mortality in a single longitudinal evaluation.
Am J Epidemiol. 2013;178(1):12-21. © 2013 Oxford University Press