Exercising regularly, eating a healthy diet, avoiding smoking, and maintaining a healthy weight were associated with a lower risk of dying over the next decade, researchers affirmed.
Adhering to a greater number of those behaviors was associated with a lower coronary calcium burden, slower progression of coronary calcium, and reduced risks of coronary heart disease events and all-cause mortality through a median follow-up of 7.6 years, according to Haitham Ahmed, MD, MPH, of Johns Hopkins Hospital, and colleagues.
Adjustment for factors that could be on the causal pathway between the behaviors and atherosclerosis -- in addition to baseline coronary calcium -- eliminated the relationship with coronary heart disease events, although the association with mortality remained strong, the researchers reported online in the American Journal of Epidemiology.
"To our knowledge, this is the first study to connect the protective effects of healthy lifestyle across baseline subclinical vascular disease, atherosclerotic progression, clinical coronary heart disease, and death in a single longitudinal evaluation," they wrote.
The behaviors assessed in the study have been used by the American Heart Association to define ideal cardiovascular health.
"The correlations between these behaviors and mortality in the present study bolster the AHA's recommendations, and the additional measure of subclinical atherosclerosis lends biologic credibility to the outcomes investigated," Ahmed and colleagues wrote.
The researchers examined data from 6,229 individuals ages 44 to 84 (median age 62) who participated in the Multi-Ethnic Study of Atherosclerosis from 2000 to 2010. All were free from clinical cardiovascular disease at baseline, but some were taking medications for hypertension (37%), dyslipidemia (16%), and diabetes (10%); 14% were taking more than one medication.
All patients were assigned a lifestyle score ranging from 0 to 4 based on the number of the following healthy behaviors to which they adhered:
• Healthy diet (adherence to the Mediterranean diet)
• Regular physical activity (150 minutes of moderate-intensity or 75 minutes of vigorous-intensity activity per week)
• Body mass index of 18.5 to less than 25 kg/m2
• Never smoking (versus ever smoking)
Only 2% of the study population had a score of 4.
There were significant associations between higher lifestyle scores and both a lower chance of developing new coronary calcium during the study and a slower progression of coronary calcium over time (P≤0.003 for both trends).
An increasing lifestyle score also was associated with declining rates of coronary heart disease events, although the trend was no longer significant in fully adjusted models.
However, the relationship between higher lifestyle scores and all-cause mortality remained significant even after full adjustment. The unadjusted hazard ratios for death -- which were not significantly altered by full adjustment -- for each lifestyle score versus a score of 0 were as follows:
• 1 (HR 0.79, 95% CI 0.61 to 1.03)
• 2 (HR 0.61, 95% CI 0.46 to 0.81)
• 3 (HR 0.49, 95% CI 0.32 to 0.75)
• 4 (HR 0.19, 95% CI 0.05 to 0.75)
In explaining the stronger association with mortality than with coronary heart disease, the researchers wrote, "Lifestyle factors likely take decades to take effect on atherosclerosis, so the more immediate effects on mortality suggest the importance of low-risk lifestyle in disease processes other than coronary heart disease alone."
The authors acknowledged that the study was limited by the lack of information on cardiorespiratory fitness. In addition, the dietary patterns of the participants -- who were all from the U.S. -- may have differed from those seen in other countries, so the findings might not be applicable beyond the U.S.
