Hypothetical Lifestyle Strategies in Middle-Aged Women and the Long-Term Risk of Stroke.

Background and Purpose- Long-term effect of lifestyle changes on stroke incidence has not been estimated in randomized trials. We used observational data to estimate the incidence of stroke under hypothetical lifestyle strategies in the NHS (Nurses' Health Study). Methods- We considered 3 nondietary strategies (smoking cessation, exercising ≥30 min/d, gradual body mass index reduction if overweight/obese) and several dietary strategies (eating ≥3 servings/wk of fish, ≤3 servings/wk of unprocessed red meat, no processed red meat, ≥1 servings/d of nuts, etc). We used the parametric g-formula to estimate the 26-year risk of stroke under these strategies. Results- In 59 727 women, mean age 52 years at baseline in 1986, the estimated 26-year risks under no lifestyle interventions were 4.7% for total stroke, 2.4% for ischemic stroke, and 0.7% for hemorrhagic stroke. Under the combined nondietary interventions, the estimated 26-year risk of total stroke was 3.5% (95% CI, 2.6%-4.3%) and ischemic stroke was 1.6% (95% CI, 1.1%-2.1%). Smaller reductions in total stroke risk were estimated under isolated dietary strategies of increased intake of fish and nuts and reduced intake of unprocessed red meat. Ischemic stroke risk was lower under reduced intake of unprocessed and processed red meat, and hemorrhagic stroke risk was lower under a strategy of increased fish consumption. Conclusions- In this population of middle-aged women, sustained, lifestyle modifications were estimated to reduce the 26-year risk of total stroke by 25% and ischemic stroke by 36%. Sustained dietary modifications were estimated to reduce the 26-year risk of total stroke by 23%.