:for health care professionals

• Hypertension
• Smoking
• Diabetes
• Metabolic Syndrome

Introduction

Cardiovascular disease remains the leading cause of death in Canada, accounting for 37% of all deaths; 21% of which is attributed to ischemic heart disease [i] . Beyond the issue of cardiovascular disease mortality, individuals living with cardiovascular disease often experience significant morbidity and disability. Health care expenditures related to cardiovascular diseases are estimated at $19 billion per year for medical and hospitalization expenses, loss of income and lost productivity [ii] . Recent decreases in cardiovascular mortality may be offset by the increasing costs to health care by increased rates of obesity, diabetes, and metabolic syndrome in the general population. Data from NHANES III survey carried out between 1988-1994 shows the age adjusted prevalence of the metabolic syndrome was 23.7% for adults over the age of 20 years. The prevalence of the metabolic syndrome between the ages of 60-69 was 43.5% [iii] . Further, NHANES III demonstrated that metabolic syndrome was significantly associated with myocardial infarction and stroke, with an odds ratio of 2.0 for these separate endpoints. The Beaver Dam population study demonstrated that the relative risk for developing cardiovascular disease was 6 times higher when patients had 4 or more of the criteria for the metabolic syndrome and that the risk of developing diabetes was 35 times higher in the same subgroup [iv] .

The metabolic syndrome is defined in qualitative terms and includes abdominal obesity, insulin resistance, elevated plasma triglyceride levels, low levels of high density lipoprotein cholesterol, and elevated blood pressure. When three of these five criteria are met (see table 1), the metabolic syndrome is clinically identified [v] .

Table 1: Risk Factor Criteria For the Metabolic Syndrome

Despite the incredible gains in the development of new diagnostic modalities and innovative revascularization techniques, cardiovascular risk reduction remains the cornerstone of treatment for patients with, or at risk for, cardiovascular disease. Despite the existence of informative guidelines outlining key assessment and treatment initiatives for those at risk, a treatment gap prevails – that is a discrepancy between recommended management and preventive therapies for individuals with or at risk for cardiovascular disease, and the care that they actually receive [vi] . In order to improve outcomes for individuals at risk for cardiovascular disease, we must create innovative approaches to bridging the treatment gap, in the effort to provide optimal care. Traditional calculations rendering risk scores estimating a person's risk for developing cardiovascular disease relative to traditional risk factors (such as Framingham risk score) do not include criteria of the metabolic syndrome (such as waist circumference, fasting glucose levels, triglyceride levels) and may underestimate the patient's level of risk. In order to intervene effectively to adequately reduce cardiovascular disease risk in patients with the metabolic syndrome, a multifactorial approach to assessment and treatment, with the cornerstones of diet, exercise and optimal medical therapy, is required protocol.

Recognizing the metabolic syndrome identifies patients with a disease entity strongly related to intra-abdominal adiposity. Recommended weight loss and lifestyle modifications have a significant effect on the disease state and represent the foundation of clinical management . For instance, the Diabetes Prevention Trial, demonstrated a modest weight loss of 5-7% led to a decrease in the incidence of diabetes, which will likely be translated into a decrease in cardiovascular disease. In order to bring about cardiac risk factor reduction and lifestyle modifications, healthcare providers must be proactive and continue to increase their knowledge of the metabolic syndrome and published guidelines. The acquired knowledge must result in clinical application. Additional efforts such as making waist circumference the "fifth vital sign" can help identify patients at increased risk early.

What causes the metabolic syndrome?
The exact cause of metabolic syndrome is not known. Most researchers believe it is caused by a combination of genetic makeup and/or lifestyle choices that contribute to central adiposity. With the metabolic syndrome, the body experiences a series of biochemical changes. Over time, these changes lead to the development of one or more associated medical conditions. The sequence begins when insulin, a hormone excreted from the pancreas, loses its ability to make the body's cells absorb glucose from the blood. When this happens, post-prandial glucose levels remain elevated. The pancreas, sensing a high glucose level in the blood, continues to excrete insulin. Loss of insulin production may be genetic or secondary to high fat levels with fatty deposits in the pancreas.

With the metabolic syndrome, what health problems might develop?
Consistently high levels of insulin and glucose are linked to many harmful changes to the body, including:

(1) Damage to the lining of coronary and other arteries, a key step toward the development of heart disease or stroke

(2) Changes in the kidneys' ability to remove salt, leading to high blood pressure, heart disease and stroke

(3) An increase in triglyceride levels, resulting in an increased risk of developing cardiovascular disease

(4) An increased risk of blood clot formation, which can block arteries and cause heart attacks and strokes

(5) A slowing of insulin production, which can signal the start of type 2 diabetes, a disease that can increases the risk for a heart attack or stroke and may also result in retinopathy, neuropathy, and nephropathy.

How can metabolic syndrome be treated or prevented?
Since physical inactivity and excess weight are the main underlying contributors to the development metabolic syndrome, getting more exercise and losing weight can help reduce or prevent the complications associated with this condition. Some of the ways risk may be reduced include:

Lose weight — Moderate weight loss, in the range of 5 -10 % of body weight, can help restore the body's ability to recognize insulin and greatly reduce the chance that the syndrome will evolve into a more serious illness.

Exercise — Increased activity can improve insulin levels. A brisk 30-minute walk a day can result in a weight loss, improved blood pressure, improved cholesterol levels and a reduced risk of developing diabetes.

Consider dietary changes — Maintain a diet that keeps carbohydrates to no more than 50 percent of total calories. Eat foods defined as complex carbohydrates, such as whole grain bread (instead of white), brown rice (instead of white), and sugars that are unrefined (instead of refined; for example cookies, crackers). Increased fiber consumption by eating legumes (for example, beans), whole grains, fruits and vegetables. Reduced intake of red meats and poultry. As much as 30 - 45 % of daily calories can come from fat, but healthy fats should be consumed such as those in canola oil, olive oil, flaxseed oil and nuts.

Management of traditional risk factors — A critical component of treatment of the metabolic syndrome is to ensure that conventional risk factors such as dyslipidemia, hypertension, diabetes are managed according to current treatment guidelines.


[i] Health Canada. (1997). Heart disease and stroke in Canada, 1997 . Ottawa, ON: Author. [ii] Health Canada. (1997). Heart disease and stroke in Canada, 1997 . Ottawa, ON: Author. [iii] JAMA. 2002; 287: 356-9. [iv] Diabetes Care. 2002; 25: 1790-1794. [v] Genest, Frohlich, Fodor, McPherson. (2003). Summary of Recommendations for the Management of Dyslipidemias and the Prevention of Cardiovascular Disease. [vi] Pearson, T.A. & Peters, T.D. (197). American Journal of Cardiology 80 (8B): 45H-52H

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