Lifestyle Factors and Risk of Ischemic and Hemorrhagic Stroke

One of the leading causes of death worldwide is stroke; for patients who survive a stroke, quality of life is decreased more than for survivors of myocardial infarction. Strategies for pharmacologic management and treatment for acute stroke are beneficial but costly and may be associated with adverse events and result in incomplete recovery; primary prevention of stroke is the most effective strategy in controlling stroke and its consequences, according to researchers. A healthy lifestyle has been proven to reduce the risk of cardiovascular disease (CVD), and combinations of multiple healthy lifestyle factors (HLFs) may be more effective than any one factor in lowering the risk of CVD. The lifestyle factors most often associated with the risk of stroke (physical activity, smoking, alcohol consumption, body mass index [BMI], and dietary factors) have not been well studied in terms of their combined effect and the risk of stroke, particularly the risk of hemorrhagic stroke. Researchers recently conducted a prospective investigation to evaluate the individual and combined associations of multiple lifestyle factors with the risks of ischemic and hemorrhagic stroke. They reported study results online in Archives of Internal Medicine [doi:10.1001/archintermed.2011.443]. The researchers conducted 5 independent cross-sectional population surveys in 6 geographic areas of Finland in 1982, 1987, 1992, 1997, and 2001. The total sample size of the 5 surveys was 38,737. After applying inclusion and exclusion criteria, the final cohort included 36,686 participants; 17,287 were male and 19,399 were female. There were 5 HLFs included in the final analysis: physical activity, smoking status, alcohol consumption, BMI, and vegetable consumption per week. During a mean follow-up period of 13.7 years, there were 1478 stroke events (1167 ischemic and 311 hemorrhagic) in the cohort. In multivariate-adjusted analyses, physical activity and vegetable consumption were inversely associated with total and ischemic stroke risk. Smoking and BMI were directly associated with total and ischemic stroke risk. Smoking was significantly and directly associated with risk of hemorrhagic stroke. The multivariate-adjusted hazard ratios (HRs) associated with adherence to 0 to 1 (reference group), 2, 3, 4, and 5 HLFs were 1, 0.68, 0.60, 0.59, and 0.35 (P<.001 for trend) for total stroke; 1, 0.72, 0.62, 0.59, and 0.32 (P<.001 for trend) for ischemic stroke; and 1, 0.55, 0.51, 0.54, and 0.39 (P=.01 for trend) for hemorrhagic stroke in men. The HRs in women were 1, 0.61, 0.50, 0.38, and 0.26 (P<.001 for trend) for total stroke; 1, 0.59, 0.52, 0.37, and 0.23 (P<.001 for trend) for ischemic stroke; and 1, 0.71, 0.45, 0.41, and 0.35 (P=.004) for hemorrhagic stroke. The researchers also estimated the reduction in total and type-specific stroke risk for participants with 3 (never smoking, moderate or high level of physical activity, and vegetable consumption ≥3 times per week), 4 (those 3 plus maintaining normal BMI), and all 5 HLFs. The partial population attributable risk percentage associated with adherence to 3, 4, and 5 HLFs, respectively, were 26.3% (95% confidence interval [CI], 17.7%-34.6%), 43.8% (95% CI, 28.6%-56.9%), and 54.6% (95% CI, 31.5%-71.6%) for total stroke; 22.7% (95% CI, 12.8%-32.2%), 45.3% (95% CI, 28.1%-59.7%), and 59.7% (95% CI, 33.7%-77.3%) for ischemic stroke, and 35.0% (95% CI, 17.4%-50.5%), 35.0% (95% CI, 0.5%-62.1%), and 36.1% (95% CI, –17.3% to 73.1%) for hemorrhagic stroke. According to the researchers, those findings suggest that 17.7% to 71.6%, 12.8% to 77.3%, and 17.4% to 73.1% of new cases of total, ischemic, and hemorrhagic strokes, respectively, could be prevented if people would have kept 3 to 5 HLFs. Limitations to the study cited by the researchers include recording information on the self-reported adherence to the HLFs (other than BMI) only at baseline, and giving each of the HLFs the same importance. In conclusion, the researchers stated that the study “demonstrates a graded inverse association between the number of HLFs and the risks of total, ischemic, and hemorrhagic stroke in both men and women. Our findings suggest the important role of promoting a healthy lifestyle in the primary prevention of both ischemic and hemorrhagic stroke.”