Lifestyle changes to prevent and control hypertension: do they work? A summary of the Canadian consensus conference.

Abstract

Most deaths in Canada are caused by cardiovascular diseases associated with atherosclerosis. Hypertension is one of the most common preventable risk factors for atherosclerosis. Worldwide, hypertension is the third leading risk factor contributing to death, surpassed only by malnutrition and smoking. In Canada, 1 in 5 adults have hypertension (blood pressure greater than 140/90 mm Hg). Diastolic blood pressure increases only until about age 60, but systolic blood pressure continues to increase with age. High systolic blood pressure is the major contributor to the 50% prevalence of hypertension in elderly Canadians, and its importance is similar to or greater than that of diastolic blood pressure as a predictor of adverse cardiovascular outcome. High blood pressure is mainly due to an interaction of environmental and genetic factors. Although the precise genetic factors influencing blood pressure are largely unknown, many of the environmental and social factors that cause high blood pressure are well known: obesity, excessive alcohol consumption, sedentary lifestyle, unhealthy diet and stress. Unfortunately, many Canadians are sedentary and have poor dietary habits. Lifestyle trends are similar in the United States, where recently there has been a decrease in blood pressure control, an increase in stroke rate and a levelling off of the previously declining rates of coronary artery disease. Because hypertension is common and treatable and because uncontrolled hypertension has serious consequences, preventive measures and control of blood pressure should be a high priority. Furthermore, given the high cost and potential complications of treating large numbers of patients with drugs, alternatives to drug therapy need to be considered for those with hypertension. Published in the supplement to this issue of CMAJ are the updated Canadian recommendations for lifestyle modifications to prevent and control hypertension. Along with the recommendations are extensive summaries of supporting clinical evidence graded according to study design. The recommendations, which are simple and straightforward, are also graded on the basis of the strength of the supporting evidence. Implementation will be difficult, but if the public, the health care system and health care professionals can rise to the challenge, the result will be a healthier population with less cardiovascular disease. The new Canadian recommendations are summarized in Tables 1–3. The recommendations include weight reduction as a means of reducing blood pressure in those who are overweight. Maintenance of a healthy body weight is an important preventive measure. Physical activity not only helps to reduce weight but also reduces blood pressure in sedentary people. Excessive alcohol intake is an important yet frequently unrecognized cause of high blood pressure; moderation of intake or abstinence from alcohol is important to prevent and control hypertension (as well as many other medical and social problems). Stress reduction through individualized cognitive behaviour modification is effective in reducing blood pressure in selected patients with hypertension, and moderation in sodium intake is effective in reducing blood pressure in hypertensive patients older than 44 years. Supplementation of the diet with calcium, potassium or magnesium is not effective in reducing blood pressure when people have adequate dietary intake. The following case scenario outlines some of the difficulties, opportunities and approaches in implementing these recommendations. Education