Prevalence of Select Risk Factors

Now that I have explained how these risk factors are the key factors in addressing your own chances of developing diseases, I would like to take some time to talk about some of the statistics regarding the prevalence of our own risk factors (this term refers to the total number of people who have a certain disease divided by the total population and is often expressed as a percentage).

Prevalence of select modifiable risk factors (Source: Behavioral Risk Factor Surveillance System):

•       1 in 5 people smoke and 2/5 exposed to 2nd hand smoke

•       1 in 10 eat the recommended guidelines for fruits and vegetables

•       3/4 people do not get enough physical activity

•       1/3 adults (ages 30-64) get less than 6 hours of sleep/night

More surprising,

• only 1 in 33 (3%) had healthy levels of all 4 lifestyle behaviors (non smoking, healthy weight, 5 fruits and vegetables per day, and regular physical activity).

Prevalence of select intermediate risk factors (Source: American Heart Association):

• Obesity/overweight – 2/3
• Abdominal obesity – 1/2
• High blood pressure – 1/3
• High Bad Cholesterol – 1/3
• Low Good cholesterol – 1/5

Prevalence of select diseases:

Diabetes – 11.3% of adults 20 and over with an additional 35% having pre-diabetes (Source: CDC)

Cardiovascular disease (includes all forms of heart disease and stroke)  –  37% (Source: American Heart Association) 

One would think that for those who already suffer from an illness, it would be more important to change and adopt healthier behaviors, but statistics do not reveal this. In fact, only 11% of patients with diabetes follow accepted dietary recommendations for saturated fat intake, and 18% of patients with heart disease continue to smoke, roughly the same as the general population's smoking rate (Lianov, Liana and Johnsson, Mark. Physician Competencies for Prescribing Lifestyle Medicine. JAMA July 10, 2010, 304(2).202-203.)

Take home message: Few people adhere to health behaviors despite of the overwhelming evidence that these risk factors lead to and cause the “killer diseases” even if we already have one of these diseases. However, even if you are in control of these lifestyle-related behaviours and have the desire to change, it is often difficult. Where can you get help? A natural place would be the doctor’s visit but as mentioned before unfortunately many doctors do not practice prevention due to a variety of reasons that I will get to in future posts. However, Preventive Medicine trained doctors are specialized in providing this type of service.

Modifiable Risk Factors

As mentioned in my previous post, we should all be focusing our attention on the actual risk factors that cause chronic diseases in order to prevent from developing them in the first place. I presented the seminal study Actual Causes of Death in the United States, 2000 that highlights the true root causes of these “killer diseases”. A newer 2009 study entitled The Preventable Causes of Death in the United States: Comparative Risk Assessment of Dietary, Lifestyle, and Metabolic Risk Factors (Danaei G, Ding EL, Mozaffarian D, Taylor B, Rehm J, et al. (2009) The Preventable Causes of Death in the United States: Comparative Risk Assessment of Dietary, Lifestyle, and Metabolic Risk Factors. PLoS Med 6(4)) presents similar findings but includes a greater variety of risk factors.

The aim of this study was to estimate the mortality (another term for death) effects of the following 12 modifiable dietary, lifestyle, and metabolic risk factors in the United States (US) using consistent and comparable methods: high blood glucose, low-density lipoprotein (LDL) cholesterol, and blood pressure; overweight-obesity; high dietary trans fatty acids and salt; low dietary polyunsaturated fatty acids, omega-3 fatty acids (seafood), and fruits and vegetables; physical inactivity; alcohol use; and tobacco smoking.

The results showed that in 2005, tobacco smoking and high blood pressure were responsible for an estimated 467,000 and 395,000 deaths, accounting for about one in five or six deaths in US adults. Overweight-obesity (216,000) and physical inactivity (191,000) were each responsible for nearly 1 in 10 deaths.

High dietary salt (102,000), low dietary omega-3 fatty acids (84,000), and high dietary trans fatty acids (82,000) were the dietary risks with the largest mortality effects. Alcohol use caused an additional 90,000 deaths.

Take home message: Smoking and high blood pressure, which both have effective interventions, are responsible for the largest number of deaths in the US. Other dietary, lifestyle, and metabolic risk factors for chronic diseases also cause a substantial number of deaths in the US.

I also want to stress that these modifiable risk factors are not only important in the development of chronic diseases but also in the development and progression of more acute diseases such as the common cold. For example, exercise has been show to reduce the chances of developing and the symptoms associated with the common cold.

I hope that I have made a strong case for addressing our own modifiable risk factors (tobacco smoking, diet, exercise and alcohol use) and that we ask these questions to our own doctors so that we focus on what really matters: preventing the development of diseases rather than focusing on managing the symptoms of diseases once they have developed.

Risk Factors and Actual Causes of Death

The leading causes of death tell us the importance of chronic diseases (also known as “killer diseases”) in our society and the evolution of a chronic diseases epidemic. I have also made a case about the potential preventability for most of these diseases. However, the story is not complete. What actually causes these diseases and how come they are so highly preventable?

Before going to answer this important question, I would like to provide a brief explanation of how we should all look at diseases. Diseases are caused by risk factors (also known as causes or determinants), which are variables that if present can lead to an increased chance of acquiring a particular disease. Risk factors, in themselves, can be subdivided into those that can be modified (for example, our diet and physical activity) and those that cannot (age and gender for example). These risk factors then are the root causes of most of the “killer diseases”.

As mentioned above, the causes of the main chronic disease epidemics are well established and well known. In fact, a seminal 1993 study by McGinnis & Foege which was updated in 2004 by Mokdad, A. H. et al. entitled Actual Causes of Death in the United States, 2000 presents what these causes or risk factors are in the following order:

1. Tobacco
2. Poor diet and physical inactivity
3. Alcohol Consumption
4. Microbial Agents
5. Toxic Agents
6. Motor vehicle crashes
7. Firearms
8. Sexual behaviours
9. Illicit drug uses

More specifically, the leading causes of death in 2000 were tobacco (435 000 deaths; 18.1% of total US deaths), poor diet and physical inactivity (365 000 deaths; 15.2%), and alcohol consumption (85 000 deaths; 3.5%). Other actual causes of death were microbial agents (75 000), toxic agents (55 000), motor vehicle crashes (43 000), incidents involving firearms (29 000), sexual behaviors (20 000), and illicit use of drugs (17 000).

The most important modifiable risk factors therefore are:

•       tobacco use.

•       unhealthy diet and excessive energy intake;

•       physical inactivity;

These account for approximately 33.3% of all deaths by themselves. It is important to note that given the continuing trends, poor diet and physical inactivity may soon overtake tobacco as the leading cause of death.

These 3 risk factors are facets of our own lifestyles (sleep and stress being the other ones) and hence the use of the term lifestyle medicine which some of us advocate and practice. Preventive medicine, the title of this blog, is a broader term that includes lifestyle medicine but goes beyond that in that it deals with all aspects of prevention (including screening for diseases, behavioural counselling, immunizations and preventive therapies).

Another way of looking at risk factors is to divide them into proximal, intermediate or distal risk factors depending on how far away they are in the causal chain of the disease. For example, the distal risk factors of diet, exercise and smoking are expressed through the intermediate or proximal risk factors of raised blood pressure, raised glucose levels, abnormal blood lipids (particularly low density lipoprotein – LDL – cholesterol), and overweight (BMI ≥ 25) and obesity (BMI ≥ 30).

The World Health Organization has released a 2005 report entitled Preventing chronic diseases: a vital investment: WHO global report which explains and diagrams these risk factors.

Another great diagram of the interrelationship of these risk factors can be found on page 54 in the report entitled: A Report Prepared for Chronic Disease in Ontario and Canada: Determinants, Risk Factors and Prevention Priorities.

The key take home point here is the following: modifiable risk factors are the root causes of the “killer diseases”. More importantly, we are in control of these modifiable risk factors and hence we can prevent most of these chronic diseases.

With this in mind we can continue to ask important questions of our own doctors. If in fact these risk factors are the true root causes of death, wouldn’t it make sense for your doctor to spend most of their time (if not all of it) assessing your risk factors, creating a risk factor profile for each of you so that a prevention plan could be put in place to deal with the risk factors and avoid disease? The truth of the matter is that due to a variety of reasons, this is not happening and most health care providers deal with symptoms of disease and never address the risk factors, in fact creating a stop-gap solution to your own health care issues. I will address this important issue in a later post.

Top health issues

Before we can determine how we can go about changing our health care system and make it work for us as consumers we need to understand what the most important health care issues are. Epidemiologists helps us understand this by compiling statistics about the causes of diseases. These health outcomes can be measured by a variety of ways and then ranking them including: causes of death, disability, quality of life and health-care associated costs among other measures. We can start by analyzing what the leading causes of death in the USA are, as most people would argue that diseases that kill us would be important to tackle first. You can find this information out at the Centers for Disease Control and Prevention (CDC), the national organization that compiles statistics on diseases (one of their many functions). If we look at data for the Leading Causes of Death from 2007 (the latest full report available from the CDC), we can appreciate that the following four conditions account for approximately 2/3 of all causes of death:
1. Heart Disease
2. Cancers
3. Stroke
4. Chronic lower respiratory diseases

It is also important to note that diabetes ranks as the sixth leading cause of death in the USA.

If one looked at the leading causes of death at the turn of last century, the list would be in sharp contrast to the current one because in the early 1900's infectious diseases (for example tuberculosis, pneumonia, diarrheal diseases and others) accounted for most of the deaths seen in society.  The comparison for the leading causes of death between 1900 and 2004 is striking.

At first glance, it would be difficult to determine what the leading causes of death in 2007 have in common. For one, they are all considered chronic diseases because most people have to live with them for many years and unfortunately this is often associated with a poor quality of life.   Most importantly, though and after decades of research, epidemiologists and physicians have been able to determine that most of these "top killer diseases" are also mostly preventable.

I want to highlight this last two points again so that everyone is able to understand and we can frame the issue:
1. The top leading causes of death in our country (and in most developed countries) are due to chronic diseases.
2. These diseases are mostly preventable.


A natural question then is: How preventable are these diseases? The answer to this question has also been elucidated by myriad epidemiological studies and the following has been found:
1. Heart Disease - 80% preventable as per the WHO Report: Preventing chronic diseases: a vital investment
3. Stroke - 80% preventable (as per the National Stroke Association)
4. Chronic lower respiratory disease - 80-90% preventable (as per the National Heart, Lung and Blood Institute)
5. Diabetes - 90% preventable (as per the Nurses Health Study - HU, F.B. et al. Diet, Lifestyle, and the Risk of Type 2 Diabetes Mellitus in Women N Engl J Med 2001; 345:790-797. September 13, 2001).
5. Cancer- over 70% preventable (as per Preetha, A. et al. Cancer is a Preventable Disease that Requires Major Lifestyle Changes. Pharm Res. 2008 September; 25(9): 2097–2116).


Again, at first glance, this is surprising to most, since the emphasis of most visits to the doctor is on treatment rather than prevention, but maybe this should be rethought based on this data. Would it not make sense to visit the doctor before developing these killer diseases ? And if so, why is this not happening? I will answer these questions in subsequent blogs. Stay tuned.

In the next blog, I will present some data on what the actual causes of these diseases are that lead to their preventability and hence the way we can prevent from developing these deadly diseases.

A new way of thinking about and managing our own health

My objective in creating this blog is to educate and inform people about the importance of the adoption of healthy behaviors in one's life. In doing so, I hope that we can all learn from each other and reflect about the way in which health care is delivered and think about ways in which it should be changed so that we can all lead healthier and more productive lives. My professional training and experience has been broad allowing me to see issues from diverse angles. I hope to bring this holistic approach to my blogs when writing about various issues. I have formal education in management, public health and medicine. I finished my Masters in Business Administration (MBA) in general management at McGill University and my Masters in Public Health (MPH) at the Johns Hopkins School of Public Health. I completed my medical specialty in preventive medicine also at Johns Hopkins and I am board certified by the American Board of Preventive Medicine, one of the recognized specialties by the American Board of Medical Specialties (ABMS), the organization that certifies medical specialties in the USA.  Furthermore, I hold unrestricted medical licenses in two states. I will always try to provide evidence to my arguments (in the form of references and links if available) to try to justify my points. More importantly, I hope that others engage in conversation in order to learn from each other. I look forward to sharing my expertise and engaging in thoughtful discussions on topics such as health, wellness, prevention, health care delivery and financing and myriad lifestyle related health behaviors such diet/nutrition, exercise, sleep, smoking cessation and stress management among others.