February 1, 2012 (Chapel Hill, North Carolina) — Individuals meeting five of seven cardiovascular health metrics outlined by the American Heart Association (AHA) had a significantly lower risk of all-cause mortality and deaths from diseases of the circulatory system compared with unhealthy individuals who met none of the metrics . The findings support the new AHA course on focusing on cardiovascular health, say investigators, noting that attaining the cardiovascular metrics outlined by the AHA could result in substantial reductions in mortality.
"I think the AHA goals really emphasize to clinicians the importance of getting after their patients and working with them," lead investigator Dr Earl Ford (Centers for Disease Control and Prevention, Atlanta, GA) told heartwire . "If they smoke, we want to get them to stop smoking. We want to control hypercholesterolemia, to bring blood pressure down, or if they have elevated blood glucose levels, to get that down as well. In terms of physical activity and diet, these are also important as well, as important as the other risk factors in one way or another."
The results of the study are published online January 30, 2012 in Circulation.
The 2020 Impact Goal
The AHA 2020 Impact Goal is to improve the cardiovascular health of Americans by 20% while also reducing cardiovascular deaths by 20%. In order to achieve these goals, the AHA adopted a new concept of cardiovascular health, one that is made up of seven components. These components include four ideal health behaviors--not smoking, body-mass index (BMI) <25 kg/m2, physical activity at goal levels, and diet that includes three or more servings of fruits and vegetables daily--and three ideal health factors, including total cholesterol <200 mg/dL, systolic blood pressure <120 mm Hg and diastolic blood pressure <80 mm Hg, and fasting plasma glucose levels <100 mg/dL.
Each of these individual behavior and risk factors are well supported by data, but there have been few studies that have addressed the relationship between clusters of the risk factors/behaviors and health outcomes. "Even though a lot of the health metrics are rooted in sound science, it's still a relatively new index," said Ford. "To me, we needed to learn about how well it predicts and how well it behaves, because this particular index hadn't really been explicitly tested."
In their study, Ford and colleagues collected data on 7622 adults 20 years of age and older participating in the National Health and Nutrition Examination Survey (NHANES) between 1999 and 2002. In the absence of AHA-specific metrics, such as dietary and glycemic measures, they used alternative measurements, such as the use of HbA1c concentrations as a stand-in for fasting plasma glucose and the Healthy Eating Index (HEI) for dietary assessments.
Overall, just 1.0% of subjects met all seven metrics of sound cardiovascular health, a disappointing number that is in line with previous studies. In total, 13.8% of subjects met five of the seven metrics of cardiovascular health and 5.4% met six metrics, while 1.5% of the study population met none of the ideal cardiovascular health criteria.
After a median of 5.8 years of follow-up, there were 532 deaths, including 186 deaths caused by diseases of the circulatory system. The data showed a significant and inverse relationship with all-cause mortality and death from circulatory diseases with an increasing number of ideal cardiovascular metrics. Compared with individuals with no ideal health measures, those with five or more had a 78% lower risk of all-cause mortality and an 88% lower risk of death from diseases of the circulatory system. The results were the same when researchers excluded patients who died in the first year of follow-up and when patients with cardiovascular disease were excluded from the analysis.
"No," said Ford when asked if he was surprised by the findings. "The preceding body of literature that used different metrics or different combinations of metrics often shows results within the same ballpark as ours, often up to a 90% reduction in subjects meeting ideal criteria. So, no, the results didn't really come as a surprise. It would have been a surprise if it hadn't."
With the exception of diet and exercise, which are behavioral components, Ford said that the criteria for ideal cardiovascular health are already being measured and assessed during routine office visits. He noted that he can't even visit his own doctor "without getting a blood pressure [cuff] slapped on my arm, regardless of why I'm there."
Cardiovascular Health Equals Population Health
In an editorial , Dr Lawrence Appel (Johns Hopkins University, Baltimore, MD), who was a member of the AHA task force that refocused on cardiovascular health, said the shift toward ideal cardiovascular health is extremely relevant to the long-term goal of eliminating health disparities and improving population health. Appel notes that disparities in four cardiovascular risk factors--smoking, blood pressure, blood glucose, and adiposity--help explain more than 50% of the racial differences in cardiovascular mortality in the US.
Regarding population health, Appel said that risk factors and behaviors that improve cardiovascular health are related to noncardiovascular outcomes and the improvement of overall population health, as shown by the significant reduction in all-cause mortality. "Efforts must now focus on interventions that assist individuals and populations in achieving and sustaining cardiovascular health, which hopefully will become the default, rather than the exception," writes Appel.
Better Middle-Age Heart Health if Prevention Starts Early
Another study published the same day in Circulation by Dr Kiang Liu (Northwestern University, Chicago, IL) used a sample of patients from the CARDIA study, including 3154 black and white subjects aged 18 to 30 years old, and reported that the maintenance of a healthy lifestyle in young adulthood is strongly associated with a lower risk of cardiovascular disease in middle age.
Similar to the study by Ford and colleagues, the researchers assessed healthy lifestyle factors such as obesity, alcohol intake, diet, physical activity, and smoking status. For these subjects, an increased number of healthy lifestyle factors in young adulthood led to a greater prevalence of a low cardiovascular disease risk profile when assessed 20 years later.
The findings have significant public-health implications, according to Liu et al, suggesting that a better heart health in midlife can be achieved if individuals adopt and maintain healthy lifestyle patterns early in adulthood.