September 20, 2012
*Minor revisions for 2012
Persons at risk of stroke and patients who have had a stroke should be assessed for vascular disease risk factors and lifestyle management issues (diet, sodium intake, exercise, weight, alcohol intake, and use of oral contraceptives and hormone replacement therapy) [Evidence Level B].
- They should receive information and counseling about possible strategies to modify their lifestyle and risk factors [Evidence Level B].
- Referrals to appropriate specialists should be made where required to provide more comprehensive assessments and structured programs to manage risk factors [Evidence Level B].
Lifestyle and risk factor information and counseling should be provided and include:
2.1.1 Healthy balanced diet: Eating a diet high in fresh fruits, vegetables, low-fat dairy products, dietary and soluble fibre, whole grains and protein from plant sources and low in saturated fat, cholesterol (< 200 mg daily for patients at increased vascular risk) and sodium, in accordance with Canada’s Food Guide to Healthy Eating [Evidence Level B].
2.1.2 Sodium: Following the recommended daily sodium intake from all sources, known as the Adequate Intake. For persons 9 to 50 years, the Adequate Intake is 1500 mg. Adequate Intake decreases to 1300 mg for persons 51 to 70 years and to 1200 mg for persons over 70 years. A daily upper consumption limit of 2300 mg should not be exceeded by any age group [Evidence Level B].3
2.1.3 Exercise: Participating in moderate exercise such as walking (ideally brisk walking), jogging, cycling, swimming or other dynamic exercise four to seven days each week in addition to routine activities of daily living [Evidence Level A].
- Patients should be counseled to achieve an accumulation of at least 150 minutes of moderate to vigorous activity per week, in episodes of 10 minutes or more (Refer to the CSEP Canadian Physical Activity Guidelines 2011 for additional information) [Evidence Level B].4
- Most stroke patients should be encouraged to start a regular exercise program.
- Supervision by a healthcare professional (physical therapist or cardiac rehab) at exercise initiation should be considered in stroke patients at risk of falls or injury, or in patients with other comorbid disease (such as cardiac disease), which may place them at higher risk of medical complications [Evidence Level C].
2.1.4 Weight: Maintaining a body mass index (BMI) of 18.5 to 24.9 kg/m2or a waist circumference of
2.1.5 Alcohol consumption: Limiting consumption to two or fewer standard drinks per day for men and one drink per day for women who are not pregnant [Evidence Level B].
2.1.6 Birth Control and Hormone Replacement Therapy: Patients who are taking estrogen-containing oral contraceptives or hormone replacement therapy in the presence of stroke should have the risks and benefits of these treatments discussed with them. Management alternatives should be considered in these patients [Evidence Level B].
A healthy lifestyle reduces the risk of an initial stroke and the risk of a subsequent stroke for patients with a prior stroke. Hypertension is the single most important modifiable risk factor for stroke. Current research reports estimate that reducing sodium in foods would abolish high blood pressure for almost one in three Canadians. Furthermore, this evidence suggests that lowering sodium consumption to adequate intake levels could reduce the incidence of stroke and heart disease by as much as 30 percent, and has a significant impact on lowering blood pressure.18 There is a growing concern for obesity in the Canadian population, especially in younger adults and this must be addressed with all patients with stroke or at risk. Regular exercise also reduces the risk of stroke and other vascular diseases.5 Research has demonstrated an increased risk of thrombosis with estrogen-based hormone therapy (both oral contraceptives and hormone-replacement therapy).
Although causes of stroke are generally different for children, lifestyle management issues as described above are equally as important for the paediatric population, particularly as the long-term risk of recurrence for children is much higher.
- Health promotion efforts that contribute to the prevention of stroke in all communities (integrated with existing chronic disease prevention initiatives) must be established.
- Coordinated and comprehensive stroke prevention should be offered by primary care providers, and a mechanism in place to ensure that stroke risk is addressed during encounters with healthcare professionals throughout the continuum of care.
- A public focus on arterial health for paediatric cases–such as diet, exercise, non-smoking, avoidance of drugs that increase stroke risk.
- National and international efforts to reduce sodium intake and increase public knowledge about the risks of sodium, directly targeting the food industry.
- Access to risk factor management programs (such as hypertension and smoking cessation programs) in all communities, primary healthcare settings and workplaces.
- Government actions to restrict smoking in public areas and discourage smoking through legislation and taxation initiatives.
- Coordinated efforts among stakeholders such as Heart and Stroke Foundations (national and provincial), the Canadian Stroke Network, public health agencies, ministries of health and care providers across the continuum to produce patient, family and caregiver education materials with consistent information and messages on risk factor management.
- Coordinated process for ensuring access to and awareness of educational materials, programs, activities and other media related to risk factor management by healthcare professionals, patients and caregivers, including advertising the availability of educational material, effective dissemination mechanisms and follow-up.
- Educational resources, that are culturally and ethnically appropriate, are available in multiple languages and that address the needs of patients with aphasia.
- Access to healthy living programs, educational materials and healthcare professionals for persons living in rural and remote locations.
- Proportion of the population with major risk factors for stroke, including hypertension, obesity, history of smoking, low physical activity, hyperlipidemia, diabetes, and atrial fibrillation (core).
- Annual occurrence rates for stroke in each province and territory by stroke type (core).
- Stroke mortality rates across provinces and territories, including in-hospital or 30-day rate and one-year rate (core).
- Percentage of the population who can identify the major risk factors for stroke, including hypertension, sodium intake, diet, weight, exercise, smoking and alcohol intake.
- Percentage of people who are aware of the healthy targets for each stroke risk factor.
- The annual readmission rate for a recurrent stroke event in patients with previous stroke or transient ischemic attack.
- For performance measures 1, 2 and 3: self-reported data can be extracted from provincial and national health surveys.
- Performance measures 4 and 5: administrative data are available at the local, provincial and national levels.
- Mortality rates should be risk adjusted for age, sex, stroke severity and comorbidities.
- Canadian Stroke Network Stroke Prevention Teaching Slide Decks: Assessment, Lifestyle Management, Medical Management http://www.strokebestpractices.ca
- Canada’s Food Guide to Healthy Eating: http://www.hc-sc.gc.ca/fn-an/food-guide-aliment/index-eng.php
- Instructions for proper waist circumference: http://www.heartandstroke.on.ca/site/c.pvI3IeNWJwE/b.4018281/k.8698/Healthy_Waists.htm
- Sodium Daily Intake Tables78
- Canadian Diabetes Association - http://www.diabetes.ca/
- PHAC Eat Well and Be Active Education Toolkit: http://www.hc-sc.gc.ca/fn-an/food-guide-aliment/educ-comm/toolkit-trousse/index-eng.php
- Sodium 101: http://www.sodium101.ca48
- Mediterranean diet: http://www.mayoclinic.com/health/mediterranean-diet/CL00011
- Stroke Prevention Best Practice Recommendations: http://www.strokebestpractices.ca/wp-content/uploads/2012/10/20120BPR_Ch2_Prevention_Final-Version_20Sept-2012F-1.pdf
- Stroke Prevention Quick Reference Guide: http://www.strokebestpractices.ca/wp-content/uploads/2012/10/CSN-Taking-Action-Poster_WEBFFF.pdf
Gillman and associates reported that, based on data collected as part of the Framingham Study, age-adjusted risk for stroke decreased as consumption of fruits and vegetables increased such that relative risk (RR) = 0.78 for each increase of three servings per day.6 This effect was independent of BMI, smoking, glucose intolerance, physical activity, blood pressure, serum cholesterol and intake of energy, ethanol and fat. A meta-analysis of fruit and vegetable consumption and stroke, which included eight studies and 257,551 individuals over a 13-year follow- up period, showed that consumption of five or more servings of fruits and vegetables per day is associated with a lower risk of stroke.7 Compared with individuals who had fewer than three servings of fruit and vegetables per day, the pooled relative risk of stroke was 0.89 (95% confidence interval [CI] 0.83–0.97) for those with three to five servings per day, and 0.74 (95% CI 0.69–0.79) for those with more than five servings per day.7
Several studies have been published in the past four years comparing different diet types in relation to stroke. Liu (2011), found that a dietary pattern characterized by high intakes of rice and vegetables and moderate intakes in animal foods was related to the lowest prevalence of stroke compare to a dietary pattern characterized by high intakes of refined cereal products, potatoes, and salted vegetables [OR = 1.96 (95% CI = 1.48–2.60); P<0.0001].8 Adjustment for conventional cardiovascular risk factors did not appreciably change the association [multivariate adjusted OR = 1.59 (95% CI = 1.16–2.17); P = 0.004]. Similarly, Mahe and colleagues (2010) found that, compared to controls, ischemic stroke patients under the age of 65 had higher saturated fatty acid scores and lower monounsaturated, omega-6, omega-3 fatty acid scores, lower fruits and vegetables, and a lower overall dietary score.9 Agnoli and colleagues (2-11) compared four diet regimes and their impact on stroke.10 These included adherence to the Healthy Eating Index 2005 (HEI-2005), Dietary Approaches to Stop Hypertension (DASH), Greek Mediterranean Index, or the Italian Mediterranean Index. This study found that all 4 diets had an inverse relationship to stroke occurrence, and that the Italian Mediterranean Index showed the best overall results [HR = 0.37 (95% CI = 0.19–0.70) and was the only one of the four diets to show an association with hemorrhagic stroke as well [HR = 0.51(95%CI = 0.22–1.20); P = 0.07)].10
Analyses of data from the Nurses’ Health Study, the Health Professionals Follow-up Study and the Women’s Health Study supported the association between consumption of fruit and vegetables and reduction of stroke risk in men and women.11,12 In an analysis of combined data from the Nurses’ Health Study and the Health Professionals Follow-up Study, Joshipura and associates found that an increase of 1 serving per day of fruits or vegetables was associated with a reduction of risk of six percent and that cruciferous vegetables, leafy green vegetables and citrus fruit (including juice) contributed most to this effect.11 Liu and colleagues reported a significant inverse relationship between consumption of fruits and vegetables and risk for cardiovascular disease including stroke.12 When individuals consuming the most fruits and vegetables were compared with those consuming the least, a relative risk reduction of 0.68 was demonstrated in favour of those with higher consumption levels.12
It is well documented that a chronically high dietary sodium intake is associated with elevated blood pressure.13-23 A high intake of sodium also has direct negative effects independent of blood pressure, such as fibrosis of the heart, kidneys and arteries, including cerebral arteries.17,20,22,23 The Institute of Medicine of the National Academies established in 2004 a daily Adequate Intake for sodium of 1500 mg and a daily Tolerable Upper Intake Level of 2300 mg for healthy adults.3 Canadian and American governments have adopted these values for setting public health policy. The Canadian Heart Health Survey found that the average Canadian consumes about 3500 mg of sodium a day, and this high sodium intake is estimated to be responsible for a additional 1 million cases of hypertension.14,15
The literature relating to sodium consumption and health published since the release of the dietary reference intakes in 2004 is currently undergoing scientific review. The reviews will be released later this year, but it is not anticipated that these will result in a revision of the current sodium intake guidelines.
Observational studies have examined the relationship between body mass index (BMI) and stroke risk. Saito (2011) compared high BMIs of 27.0 to 29.9 kg/m2 and BMI of >= 30.0 kg/m2 to a ‘healthy’ BMI between 23.0 and 24.9 kg/m2.24 They reported hazards ratios for increased stroke risk as 1.09 and 1.25 for men, and 1.29 and 2.16 for women. In addition, in women a weight increase of greater than 10% over the previous five years was also associated with increased stroke risk. Bazzano (2010) reported similar findings in a study of Chinese men and women, where the hazard ratios for increased stroke risk were 1.43 for persons considered overweight (BMI 25.0 to 29.9 kg/m2) and 1.72 for those who were obese with a BMI of 30 kg/m2 or greater. 25 Yatsuya (2010) found similar results (men – HR of 1.81; women – HR of 1.65), and further reported that when the analysis adjusted for systolic blood pressure, much of the BMI risk affect was attenuated.26
Some researchers have suggested that waist circumference is a preferred measurement of obesity than BMI. 27-29 Dalton et al (2003) compared BMI, waist circumference (WC) and waist to hip ratio (WHR) for cardiovascular disease risk.30 Overall WHR showed the strongest correlations in unadjusted results, and these differences diminished when the results were adjusted for age. Women showed relationships between elevated blood pressure and both WHR and BMI. Jannsen (2004) calculated several regression models to examine the predictability of BMI and WC for hypertension, dyslipidemia and metabolic syndromes. 31 They reported that waist circumference was a better overall predictor of obesity-related CVD risk. Yau (2011) measured waist circumference in a case-controlled observational study of independent risk factors for stroke, and reported an odds ration of 4.0 for persons with increased waist to hip ratios. 32 Zhu et al (2004) identified formulas for calculating cardiovascular risk using a combination of BMI and WC.33 They determined that in while males a formula of 0.68 x BMI + 0.32 x WC was most predictive; yet in females the WC alone was a strong predictor of cardiovascular risk. Clark and colleagues (2012) caution that the current parameters for waist circumference may not be applicable to African-Americans and that research should be conducted to establish appropriate measurement standards for this population.34
Physical activity is an important modifiable lifestyle factor that can influence both the primary and secondary prevention of stroke. Reimers and colleagues (2009) published a meta-analysis that showed physical activity reduced the risk of all stroke types (RR=0.32) for men and women combined.35 The results were derived from 33 prospective cohort studies and 10 case-control studies that addressed the potential effect of physical activity on stroke.
Lee and collaborators published a meta-analysis of 23 studies published between 1983 and 2002 examining the association between physical activity and stroke incidence or mortality.36 Eighteen cohort studies and 5 case–control studies were included for analysis. When both types of study were examined together, highly active individuals were reported as having a 27 percent lower risk of stroke than individuals who were designated as “low active.” Individuals who were designated as moderately active also had a significantly reduced risk of stroke when compared with low active individuals (RR = 0.80, p < 0.001). The benefits of high and moderate levels of activity were reported for both ischemic and hemorrhagic strokes. The meta-analysis showed increasing benefit with increasing activity, a dose–response relationship was also established. However, as Lee and collaborators pointed out, given the range of definitions of “level of physical activity” in the studies included for assessment, their analysis suffered from the lack of a single, cohesive definition of what constitutes low, moderate and high levels of activity.36 The question of what type or quantity of activity is required to reach a moderate level and so to benefit from a 20 percent reduction in the risk of stroke is one that needs to be investigated by means of a randomized controlled trial.
Patient adherence is important for physical activity to be effective. Jurkiewicz and colleagues (2011) found that patients that attended a rehabilitation center regularly had higher adherence to an exercise program compared to participants that had graduated and were required to do solely home-based exercise.37 Common factors preventing exercise that were reported by patients included: lack of motivation, musculoskeletal issues, and fatigue.
A meta-analysis of 35 observational studies examining the effects of alcohol consumption on stroke risk revealed a significant (p = 0.004) J-shaped relationship between the amounts of alcohol consumed per day and the risk of ischemic stroke.38 In that analysis, individuals who consumed 1 to 2 drinks per day had the least risk for ischemic stroke (RR = 0.72), while those having more than 5 drinks per day had the most risk (RR = 1.69) when compared with a group of abstainers.39 The analysis also confirmed that alcohol consumption has a linear, dose-dependent effect on risk of hemorrhagic stroke. Heavy drinking (more than 5 drinks per day) was associated with a relative risk of hemorrhagic stroke of 2.18. Irregular and binge drinking (more than 5 drinks at one sitting) have also been associated with an increase in risk for hemorrhagic stroke.39
Data from the Copenhagen City Heart Study were used to examine whether the type of alcohol consumed was related to the apparent decreased risk of ischemic stroke with moderate alcohol consumption.40 The overall beneficial effect of moderate alcohol consumption was confirmed; however, the benefit was seen mostly among those individuals who consumed wine. Wine drinking on a daily, weekly or monthly basis was associated with reduced risk of ischemic stroke (RR = 0.68, 0.66 and 0.88, respectively, after adjustments for age, sex, smoking, BMI, physical activity, systolic blood pressure, cholesterol, antihypertensive treatment, triglycerides, education, and diabetes). No similar effect was demonstrated among drinkers of beer or spirits. Both Kiechl and associates and Sacco reported the greatest risk reduction (RR = 0.41 and 0.40, respectively) among wine drinkers; however, this was not significantly lower than among drinkers of beer, liquor or a combination of types of alcohol.41,42
Oral Contraceptives, Hormone Replacement Therapy and Stroke risk in Women
Women taking oral contraceptive or hormone replacement therapy may be at an increased risk of stroke.43-49 Bath and Gray (2005) conducted a meta-analysis to assess the association between hormone replacement therapy and subsequent stroke.46 They identified 28 trials that included almost 40,000 patients. Their analysis found that hormone replacement therapy was associated with significant increases in total stroke (OR =1.29, 95% CI 1.13 to 1.47), non-fatal stroke (OR=1.23, 1.06 to 1.44), stroke leading to death or disability (OR=1.56, 1.11 to 2.20), ischaemic stroke (OR=1.29, 1.06 to 1.56), and a trend to more fatal stroke (OR=1.28, 0.87 to 1.88). They also found that hormone replacement therapy was not associated with haemorrhagic stroke (OR=1.07, 0.65 to 1.75) or transient ischaemic attack (OR=1.02, 0.78 to 1.34). Similarly, Renoux and colleagues (2010) found that, compared to non-users, women using both low and high dose oral hormone replacement therapy had a higher rate of stroke (Rate Ration= 1.28, 1.15-1.42); however, the use of low-dose transdermal hormone replacement therapy did not increase the risk of stroke (Rate Ratio=0.95, 0.75-1.20).
Cole and colleagues (2007) identified women using transdermal contraceptive therapy and norgestimate-containing oral contraceptives.48 There was an increase in the rate of venous thromboembolism among transdermal contraceptive system users compared with norgestimate-containing oral contraceptives users (incidence rate ratio 2.2, 95% confidence interval [CI] 1.3-3.8). Stroke rate differences could not be calculated. In a large cohort study of 49, 259 Swedish women aged 30-49, found that the risk of hemorrhagic stroke was not statistically significantly raised in women who started using oral contraceptive over the age of 30 (Hazard ratio=2.3, 0.8-6.8).49