Healthy diet and lifestyle and risk of stroke in a prospective cohort of women

Abstract

Objective: To investigate the association between a low-risk lifestyle and risk of stroke.

Methods: The study population comprised 31,696 women, in the population-based Swedish Mammography Cohort who at baseline had completed a questionnaire about diet and lifestyle and were free from cardiovascular disease and cancer. We defined a low-risk lifestyle as a healthy diet (top 50% of a Recommended Food Score), moderate alcohol consumption (5-15 g/d), never smoking, physically active (walking/bicycling ≥40 min/d and exercise ≥1 h/wk), and body mass index below 25 kg/m(2). Stroke cases were identified from the Swedish National Patient Register and the Swedish Cause of Death Register.

Results: We ascertained 1,554 incident stroke cases, including 1,155 cerebral infarctions, 246 hemorrhagic strokes, and 153 unspecified strokes during 10.4 years of follow-up. The risk of stroke, in particular cerebral infarction, decreased steadily with increasing number of low-risk lifestyle factors. Compared with no low-risk factors, the multivariable relative risks (95% confidence interval) of cerebral infarction across increasing number of low-risk factors (1-5) were 0.72 (0.56-0.93), 0.67 (0.52-0.85), 0.57 (0.44-0.74), 0.54 (0.40-0.73), and 0.38 (0.20-0.73).

Conclusions: These findings indicate that a low-risk lifestyle can substantially reduce the risk of stroke, especially cerebral infarction.

Figure 1. Relative risks^a with 95% confidence interval of cerebral infarction (A) and total stroke (B) according to number of low-risk lifestyle factors^b among 31,696 Swedish women, 1998–2008

^a Adjusted for age, education, aspirin use, history of diabetes, diagnosis of atrial fibrillation, family history of myocardial infarction before 60 years of age, total energy intake, and Non-Recommended Food Score. ^b Low-risk factors was defined as scoring within the top 50% of a Recommended Food Score, moderate alcohol consumption (5–15 g/d), never smoking, physically active (≥40 min/d of walking/bicycling and ≥1 h/wk of exercise), and BMI <25 kg/m². Compared with the reference group with no low-risk factors (4.8% of the study population), the adjusted relative risks (95% confidence interval [CI]) of cerebral infarction across increasing number of low-risk factors (1–5) were 0.72 (0.56–0.93), 0.67 (0.52–0.85), 0.57 (0.44–0.74), 0.54 (0.40–0.73), and 0.38 (0.20–0.73). The corresponding relative risks (95% CI) for total stroke were 0.77 (0.61–0.96), 0.76 (0.61–0.95), 0.65 (0.52–0.82), 0.60 (0.46–0.78), and 0.46 (0.27–0.78).