Professor Michael Hanna, Consultant Neurologist, highlights recent research published in a major Neurology Journal which provides new evidence that it is never too late to adopt a healthy life style to reduce the risk of stroke.
What is a stroke?
A Stroke is also known as a cerebrovascular accident (CVA) and occurs when the blood flow to part of the brain is acutely interrupted causing brain cell death and injury. There are two main types: ischemic stroke is due to lack of blood flow and hemorrhagic stroke is due to bleeding. They result in part of the brain not functioning properly. Symptoms may include loss of the ability to feel or move on one side of the body, problems understanding or expressing language, slurred speech, dizziness, or loss of vision to one side among others. Symptoms usually come on suddenly. Every year there are approximately 152,000 strokes in the UK. Most people affected are over 65, but anyone can have a stroke.
What are the risk factors for stroke?
The main risk factors for stroke are high blood pressure, smoking, high blood cholesterol, obesity, lack of exercise, diabetes, previous TIA, heart valve disease and heart rhythm problems such as atrial fibrillation.
About this recent study
The recent research article entitled the "Primary prevention of stroke by a healthy lifestyle in a high-risk group" was published by a group from the Karolinska Swedish National Research Institute [Larsson SC1, Åkesson A2, Wolk A2] in the journal Neurology recently (Neurology. 2015 Jun 2;84(22):2224-8. doi: 10.1212/WNL Epub 2015 May 1.)
Aims of the study
The researchers set out to examine the impact of a healthy lifestyle on stroke risk in men who were already at a higher risk of stroke because they had pre-existing risk factors such as other cardiovascular diseases, diabetes or hypertension.
Methods used in the study
The researchers had access to data on a very large population of 11,450 Swedish men who had a history of hypertension, high cholesterol levels, diabetes, heart failure, or atrial fibrillation. The participants had completed a very detailed questionnaire about diet and lifestyle and were free from stroke and ischemic heart disease at baseline (January 1, 1998). A healthy lifestyle was defined using the following five factors:
- low-risk diet (≥5 servings/day fruits & veg & <30 g/day processed meat
- not smoking
- ≥150 min/week of physical activity,
- body mass index of 18.5 to 25 kg/m2
- low to moderate alcohol consumption (>0 to ≤30 g/d).
Ascertainment of stroke cases was accomplished through linkage with the National Inpatient Register and the Swedish Cause of Death Register.
The results of the study
During a mean follow-up of 9.8 years, the researchers observed that 1,062 of the 11450 patients had a stroke. They found that the risk of stroke decreased with an increasing number of healthy lifestyle factors. By doing a specialized statistical analysis, called multivariable analysis, they were able to show that the relative risk of total stroke for men who achieved all 5 healthy lifestyle factors compared with men who achieved 0 or 1 factor was 0.28 (95% confidence interval 0.14–0.55). The corresponding relative risks (95% confidence interval) were 0.31 (0.15–0.66) for ischemic stroke and 0.32 (0.04–2.51) for hemorrhagic stroke.
Conclusions from this study
This is a large study from a major international research institute in Sweden. There is a very well developed national disease monitoring programme in Sweden which records disease incidence, including stroke, in large populations of patients. This study was done on 11450 men who already had a history of stroke risk factors including one or more of the following; hypertension, high cholesterol levels, diabetes, heart failure, or atrial fibrillation. The researchers were able to analyze follow up data over the next 9.8 years and assess the relationship between the 5 key lifestyle factors and the incidence of stroke.
They found that even in this group of men with preexisting risk factors those that had more of the healthier lifestyle choices reduced their risk stroke.
Take Home Message
Even in men with pre-existing risk factors for stroke, health lifestyle choices can reduce the risk of stroke
More information for patients available at the stroke association website