By Lance C. Dalleck, Ph.D.
Present-day society affords numerous opportunities to indulge. Humans constantly wrestle with increased levels of saturated fat and salt, decreased levels of fiber, widespread use of alcohol and tobacco, and higher consumption of calorically dense food. And, of course, there is an increasing propensity to remain sedentary for most of the day. This lifestyle has wreaked havoc with our biochemistry and physiology, resulting in a global epidemic of chronic diseases, such as cardiovascular disease and diabetes. It is not surprising, then, that public health experts have increasingly stressed the importance of encouraging healthy habits early in childhood to prevent the emergence of risk factors that contribute to chronic disease. Though this preventative approach is ideal, what if a person reaches middle age and has multiple risk factors? Is it possible to reverse the process of chronic diseases, such as type 2 diabetes or heart disease? Can we make up for the sins of our youth by adopting a healthy lifestyle later in life?
Three Types of Prevention: Primordial, Primary and Secondary
In 2008, 811,940 deaths were attributed to cardiovascular disease (CVD), according to the American Heart Association (AHA, 2012). In fact, since 1900, with the exception of 1918 and 1919, when there was a worldwide influenza pandemic, the most common cause of mortality among American adults has been CVD. Given this widespread mortality, various preventative strategies have been developed and implemented to combat the epidemic of CVD (Franklin and Cushman, 2011). These prevention tactics fall into one of the following three categories:
- Primordial prevention: Measures taken to prevent the development of risk factors. In other words, the focus of primordial prevention is on promoting a lifestyle that will thwart risk factors for chronic diseases from ever arising in the first place.
- Primary prevention: Actions taken to treat existing risk factors. For instance, for a sedentary individual who is overweight and has developed hypertension, a primary prevention program might focus on increasing physical-activity levels to attenuate his or her known risk factors.
- Secondary prevention: Measures taken to prevent recurrent clinical events, most commonly cardiovascular events. In this scenario, an individual who has experienced a heart attack might be encouraged to attend a cardiac rehabilitation program to change his or her lifestyle to help reduce the chances of another heart attack occurring.
Before we explore the question of whether or not you can turn the ship around later in life, let’s take a look at the compelling evidence for why it’s a good idea to look after yourself starting early in life.
Healthy Eating and Regular Exercise: Start Early and Do it Often
There is a wealth of research demonstrating that bad habits, such as smoking, physical inactivity and poor diet, contribute to the development of numerous health risk factors, including obesity, high cholesterol, hypertension and type 2 diabetes. Conversely, there is an equal amount of scientific evidence to highlight a reduced risk of the aforementioned risk factors if a healthy lifestyle is adhered to. What is the impact of developing risk factors earlier in life as a consequence of an unhealthy lifestyle in terms of lifetime risk of heart disease? Consider the following three studies, which highlight the importance of primordial prevention:
In 2004, it was reported that women ages 18 to 39 years with one or more major CVD risk factor (hypertension, high cholesterol, smoking, type 2 diabetes, obesity) were at two to 10 times greater risk of mortality from CVD compared to their same-aged counterparts with no CVD risk factors (Daviglus et al., 2004).
In 2006, it was found that individuals who were able to reach 50 years of age without any risk factors had a markedly lower lifetime risk of CVD (Lloyd-Jones et al., 2006). Specifically, it was shown that men and women with no CVD risk factors, in relation to their counterparts with two or more CVD risk factors, had the following lifetime risks for CVD:
Moreover, these same authors reported that men and women who are risk-factor free at 50 years of age live approximately eight to 10 years longer than those individuals who reach age 50 with two or more CVD risk factors.
- Men: 5.2 percent vs. 68.9 percent
- women: 8.2 percent vs. 50.2 percent
More recently, in 2012, the lifetime risk of CVD based on risk-factor burden was determined by a group of researchers (Berry et al., 2012), who combined the results of 18 different studies that included a total of 257,384 men and women. Among individuals 55 years of age, those with two or more major CVD risk factors had a three- to six-times greater risk of death from CVD compared to those with an optimal CVD risk factor profile (i.e., non-smoker, non-diabetic, normotensive and normal cholesterol).
Clearly, making it to middle age without the burden of CVD risk factors is extremely important. The substantially decreased CVD mortality risk linked to an absence of CVD risk factors up to middle age underscores the power of primordial prevention. While, ideally, everyone would reach 50 without the burden of CVD risk factors, the harsh reality is that most individuals in our society will arrive at that age with numerous CVD risk factors in tow, largely due to the poor health choices they made throughout their lives. Now what? Is there any chance for redemption? Can we undo the damage done by our youthful indiscretions?
It’s Never Too Late
Fortunately, research suggests that it is never too late to start making healthy lifestyle changes. Here are four studies to give all of us some hope:
- Greater energy expenditure can lead to coronary artery disease stabilization and regression. In the early 1990s, Hambrecht and colleagues completed a classic study aimed at determining whether the process of coronary artery disease (CAD) could be modified through a lifestyle intervention in patients with known heart disease. After one year the investigators found an important link between the amount of weekly energy expenditure and the status of CAD in patients. Specifically, those individuals who expended 1,500 kcal/week (amounting to approximately three hours of exercise per week) showed no further blockage of the coronary vasculature. Furthermore, individuals exercising enough to expend 2,200 kcal/week (amounting to about six hours per week) demonstrated a regression in their CAD. The regression in CAD meant that, compared to the onset of the research trial, at the conclusion of the study there was less plaque blocking blood flow through the coronary vessels. These results are exciting, and should encourage those who have been diagnosed with heart disease, because it suggests that the chronic condition can be successfully managed if the client is willing to do enough exercise. It is critical to note that the volume of exercise required to elicit CAD stabilization is equivalent to current national physical-activity guidelines (i.e., 30 minutes of moderate-intensity exercise most days of the week). And yet, if a patient is targeting CAD regression, the volume of exercise must then be doubled to one hour/day for virtually every day of the week (Hambrecht et al. 1993).
- Lifestyle intervention vs. medication. In 2002, the Diabetes Prevention Program Research Group reported findings from a study that examined whether impaired fasting blood glucose (a.k.a., prediabetes) was reversible. To test this, 3,234 prediabetic and obese individuals (mean age 51 years) were randomized to either a lifestyle intervention or medication treatment group. Individuals in the lifestyle intervention group were directed to exercise at a moderate intensity for 150 minutes per week, while individuals in the medication group were directed to take metformin, a glucose-lowering medication. After an average follow-up of three years, it was reported that the lifestyle intervention was twice as effective as medication at reducing the incidence of type 2 diabetes. Given that 40 percent of American adults are prdiabetic, and that the risk of type 2 diabetes is five- to seven-times greater for those individuals relative to persons with normal fasting blood glucose levels, these results highlight the exciting possibilities of primary prevention. It is possible for individuals, even those who are sedentary, obese and pre-diabetic, to engage in an active lifestyle that fulfills the consensus physical-activity recommendation and substantially reduce their risk of developing type 2 diabetes. And they may be able to do it without relying on medications (Bianchi et al., 2011).
- Lifestyle intervention vs. surgical procedure. In 2004, Hambrecht and colleagues published the results of another study that compared the effectiveness of a lifestyle intervention to a surgical procedure for individuals with stable CAD. Stable CAD refers to a condition where the extent of plaque accumulation in the coronary vasculature does not compromise adequate blood flow at rest; however, during physical exertion and exercise the blockage hampers blood flow enough to cause chest discomfort and other symptoms. One option for patients with stable CAD is stenting, where a small wire mesh is inserted into the anatomical location of the coronary vessel with the biggest blockages. A small balloon is used to expand the wire mesh and alleviate the blockage, thus restoring more normal blood flow through the coronary vessel. A major limitation to stenting is that it can only be applied to the most critical regions blocked in the coronary vessels. Because CAD is a systemic disease of the coronary vasculature, Hambrecht and his group wanted to determine if a lifestyle intervention consisting of three hours per week of moderate-intensity exercise, which hypothetically could provide a more widespread physiological benefit, would be superior to stenting.
After one year, the lifestyle-intervention group experienced fewer clinical events (e.g., heart attack or surgical procedure), increased their fitness levels by 16 percent, and did so with a program that was half the cost of the stenting procedure. These provocative findings certainly lend merit to the notion that one can make up the sins of one’s younger years with healthy choices later in life.
- Stop smoking to increase longevity. A landmark study that observed 34,439 physicians for 50 years found that, on average, lifetime smokers (from adulthood onwards) died 10 years sooner than nonsmokers (Doll et al., 2004). Yet, it was also shown that individuals who quit smoking at either the ages of 40 and 60 years improved their life expectancy by approximately nine and three years, respectively. Smoking cessation at the age of 30 was found to nearly eliminate the risk of dying prematurely. Regrettably, smoking continues to be the leading cause of preventable mortality and disability in the United States (Schroeder and Warner, 2010). Nonetheless, it is encouraging that prevention, in the form of smoking-cessation programs, even when taken up later in life, leads to increased longevity.
Clearly there is a tremendous upside to promoting primordial prevention whenever possible. However, given the rampant prevalence of obesity, diabetes and heart disease throughout our present-day society, you will more often be required to employ primary and secondary prevention strategies with your clients. Yet, regardless of how self-destructive clients might have been in earlier decades in terms of their health, you can reassure them that it is never too late to seek redemption by adopting healthy practices.
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Lance C. Dalleck, Ph.D., is academic coordinator of the cardiac rehabilitation postgraduate program at the University of Auckland in New Zealand. His research interests include improving exercise performance and health outcomes through evidence-based practice, quantifying the energy expenditure of outdoor and non-traditional types of physical activity, and studying historical perspectives in health, fitness and exercise physiology.