Prevention paradox between stroke and multiple potential risk factors using data from a population-based cohort study

Abstract Previous studies have found the prevention paradox in the association between stroke events and a single specific risk factor, indicating that a population-based strategy may be more effective than a high-risk-based strategy for prevention. We tested the hypothesis that the prevention paradox does not apply when focusing on multiple potential risk factors simultaneously. The study cohort included 9051 individuals from Japan aged 40–89 years. The time-dependent Cox proportional-hazards models were used to identify the primary risk factor associated with stroke onset. We classified participants based on risk factors in two distinct ways: 1) classifying the high-risk group participants according to a single specific risk factor that had a large association with stroke in both sexes and all ages and 2) classifying the high-risk group participants according to 1–3 risk factor(s) including hypertension, hyperglycemia, and/or dyslipidemia. Then, we compared the proportions of the total number of participants who developed stroke in both groups to assess the prevention paradox. We found that hypertension was a primary risk factor for stroke incidence, regardless of sex and age. The percentage of patients with a single specific risk of and developed stroke was 46%–63%, while the percentage of patients with 1–3 risk factor(s) was 71–83%. This finding leads to the conclusion that the prevention paradox does not hold when multiple stroke risk factors were associated, suggesting that a high-risk-based strategy that focuses on patients with multiple risk factors may be more effective in preventing strokes.