Cardiovascular Disease Is Becoming Younger in the World


Cardiovascular disease is becoming younger. Deaths from cardiovascular disease are declining, especially in high-income countries. But at the same time, the incidence of cardiovascular diseases is increasing among adolescents and young adults. This phenomenon has been described as “the inverse epidemic”: While mortality among older adults is decreasing, the prevalence of cardiovascular risk factors earlier in life has been increasing worldwide. This trend raises important questions regarding public health interventions to prevent or manage cardiovascular disease at different stages of life. What do we know about this inverse epidemic? Can it be explained by genetic factors? How can prevention programs be adjusted to tackle this new phenomenon? Keep reading to learn more about the inverse epidemic of cardiometabolic disease and its implications for health policy and research.


What is the Inverse Epidemic of Cardiovascular Disease?

The inverse epidemic of cardiovascular disease refers to the global decrease in mortality rates from cardiovascular diseases (CVD) among older adults, coupled with an increase in CVD risk factors in adolescents and young adults. This phenomenon is not only evident in high-income countries but also in low- and middle-income countries, albeit to a lesser degree. It raises important questions regarding public health interventions to prevent or manage CVD at different stages of life. When the initial results of the INTERHEART study were published in 2004, they came as a surprise. The study compared more than 18,000 cases with more than 28,000 controls from 52 countries and found that more than 70% of acute myocardial infarctions (AMI) could be attributed to 10 modifiable risk factors. More importantly, risk factors were found to be less prevalent in older adults than in younger adults. This observation led INTERHEART investigators to describe this inverse relationship between age and the prevalence of risk factors as an “epidemic.” Today, the inverse epidemic of CVD is widely acknowledged as a worldwide phenomenon.


Why Is Cardiovascular Disease Becoming Younger?

The reasons for the inverse epidemic of CVD are not entirely clear. However, there are several hypotheses to explain this phenomenon: The first hypothesis is that the epidemiological transition has finally reached low- and middle-income countries. CVD mortality rates are declining at the same time in high-income countries, middle-income countries, and low-income countries. Since the 1980s, there has been a significant reduction in mortality rates from heart disease in high-income countries. At the same time, CVD mortality rates are declining in middle-income countries, while they are increasing in low-income countries. This could result from a global reduction in risk factors such as smoking, blood pressure, and cholesterol levels. But the epidemiological transition alone cannot explain the inverse relationship between age and the prevalence of CVD risk factors.


Cardiovascular Risk Factors in Adolescents and Young Adults

The second hypothesis is that the prevalence of CVD risk factors is increasing at younger ages. This hypothesis is supported by data showing that the percentage of adolescents with high cholesterol levels has increased over the past decades in both high-income and low-income countries. Moreover, the prevalence of obesity and type 2 diabetes is higher among adolescents and young adults than among older adults. The increase of CVD risk factors at younger ages is partly attributable to the phenomenon of metabolic programming. This theory suggests that the adverse environment during critical periods of development may have long-term effects on health by permanently reprogramming the metabolism and fat tissue storage. A growing body of evidence suggests that the risk factors for CVD are present at younger ages today than 30 years ago.


The Dark Side of the Inverse Epidemic

The third hypothesis is that the inverse relationship between age and the prevalence of CVD risk factors is not entirely beneficial. Instead, it may represent a “dark side” of the epidemic. This hypothesis is supported by data showing that adolescents and young adults are still at a high risk of CVD. They have a higher prevalence of risk factors that increase the risk of AMI, such as hypertension and high cholesterol levels. This hypothesis also draws attention to the challenges that the inverse relationship between age and the prevalence of CVD risk factors presents for public health. Prevention programs need to be adjusted to target adolescents and young adults. This is particularly challenging because most cardiovascular risk factors such as obesity and metabolic disorders are hard to detect in adolescents.


Conclusion

The inverse epidemic of CVD is a complex phenomenon that is likely to be explained by the interaction of several factors. A key question is why the prevalence of CVD risk factors is increasing at younger ages. Some hypotheses suggest that this trend is related to adverse environmental conditions during critical periods of development. It is important to note that the inverse epidemic of CVD is not beneficial for everyone. The burden of CVD remains high among older adults, particularly those living in low- and middle-income countries. It is essential to understand the mechanisms behind this inverse epidemic in order to design appropriate interventions. Public health policies, school health programs, and clinical management of cardiovascular risk factors among adolescents and young adults need to be adjusted to take into account this new reality.

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