Cardiovascular disease (CVD) is one of the most significant causes of global mortality. Several factors, such as obesity, poor diet, lack of physical activity, dyslipidemia, smoking, diabetes, and high blood pressure, have been identified to enhance the risk of CVD events. In 2010, the American Heart Association (AHA) constructed Life’s Simple 7, which included seven lifestyle-based goals that could help achieve ideal cardiovascular health (CVH).
Study: Association of the American Heart Association’s new “Life’s Essential 8” with all-cause and cardiovascular disease-specific mortality: prospective cohort study. Image Credit: H_Ko / Shutterstock
Background
Even though the implementation of the interventions in Life’s Simple 7 revealed a positive effect on CVH, its prevalence was significantly low in the US population. Prior studies have indicated some limitations associated with Life’s Simple 7, which include not considering important factors like sleep health, basic additive scoring, and insensitivity towards interindividual differences and intraindividual change.
Considering the aforementioned limitations of Life’s Simple 7, the AHA’s Strategic Planning Task Force and Statistical Committee have recently updated the recommendations and created Life’s Essential 8, which focuses on optimal CVH. A recent BMC Medicine study has investigated the performance of the updated recommendations in relation to mortality.
"Life’s Essential 8 are the key measures for improving and maintaining cardiovascular health, as defined by the American Heart Association. Better cardiovascular health helps lower the risk for heart disease, stroke and other major health problems." - American Heart Association
About the Study
The data for this study was obtained from the National Health and Nutrition Examination Survey (NHANES), conducted between 2005 and 2018. The NHANES is an ongoing survey with a multistage probability sampling design based on the US civilian population.
Data were provided on 39,749 adults who were above 20 years of age. However, based on eligibility criteria and study requirements, a total of 19,951 adults between 30 and 79 years of age were considered in this study.
Information on diet, sleep health, nicotine exposure, i.e., vaping devices, e-cigarettes, second-hand tobacco smoke, and physical activities, were self-reported by participants by answering the questionnaire designed by the authors. The body mass index (BMI) of the participants was recorded along with their blood lipid content, i.e., the total and high-density lipoprotein (HDL) cholesterol and blood glucose content. The blood pressure levels of the participants were also recorded.
Study Findings
Participants with a high level of total or individual CVH metrics in Life’s Essential 8 were at a decreased risk of all-cause and CVD-related mortality. Notably, a linear dose–response correlation was observed between increased total CVH metric score and reduced risk of all-cause and CVD-specific mortality.
The adjusted population-attributable fractions (PAFs) estimates indicated that around 33% of all-cause mortality and 42.9–70.6% mortality risk due to CVD, related to low or intermediate total CVH. This could be avoided by achieving a high CVH metric score. Hence, the study's finding supports the updated CVH metrics in their role in predicting future mortality as part of Life’s Essential 8.
A previously conducted meta-analysis elucidated the effectiveness of Life’s Simple 7 and determined a linear dose–response association. This study indicated that a one-point increase in the ideal CVH metric score leads to a subsequent reduction in risk of all-cause and CVD-specific mortality; however, this study used a crude additive scoring method, an overtly simplified approach. In contrast, the current study used an increased scoring algorithm ranging between 0 and 100, as recommended in Life’s Essential 8. A higher total CVH metric score was strongly linked with reduced risk of all-cause and CVD-specific mortality.
It was found that physical inactivity was a major factor that influences both all-cause and CVD-specific mortality. Although the association between physical activity and reduction in mortality risk is not new, the current study validated the updated scoring of physical activity in Life’s Essential 8. Nicotine exposure was the second significant contributor to all-cause mortality. The following important contributor to mortality is an unhealthy diet, and in Life’s Essential 8, the AHA recommended the Healthy Eating Index 2015 to determine the association between dietary quality and mortality.
Improvements in the CVH score have been represented through the spline plots. A linear dose response indicates that any improvement would matter, such that those with lower CVH scores could benefit from small improvements as well.
Overall, lifestyle modifications, along with appropriate public education and awareness, improve CVH scores and, thereby, reduce CVD-related mortality. While assessing sleep health as a metric for CVH score, it was found that an increase in sleep metric score significantly lowered the risk of all-cause mortality. Nevertheless, it must be noted that the adjusted PAFs of sleep health with mortality were relatively small, indicating that this CVH metric might not be as important as expected. In line with previous studies, blood glucose was found to be an important contributor to CVD-related mortality.
Conclusions
The current study has some limitations, including consideration of self-reported dietary intake, nicotine exposure, sleep health, and physical activity, which can lead to recall bias. Furthermore, there is a possibility of the existence of confounding factors influencing the research findings. Finally, changes in the metric trajectories over time were not considered.
Despite the limitations, one of the critical outcomes of this study is the observation that minor improvements in total CVH score could significantly reduce the risk of all-cause and CVD-specific mortality.
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