Estimating the impact of risk factor reduction on dementia prevalence in New Zealand

INTRODUCTION: We aimed to estimate the prevention potential associated with a reduction in risk factor prevalence and the subsequent impact on dementia prevalence projections over time METHODS: We calculated potential impact fraction (PIF) of a 15% and 25% proportional reduction in risk factor prevalence for 12 modifiable dementia risk factors for New Zealand, and individually for the four main ethnic groups, then modeled this over a 30-year period. RESULTS: The PIF for the total NZ population following a 15% risk factor reduction was 14.6% (95% confidence interval: 7.7-21.1) Modeled projections demonstrated prevalence reduction over time, from 1.0% at 10 years to 4.2% at 30 years. PIF and modeled reductions at all time points were higher for Māori and Pacific peoples. DISCUSSION: The projected impact of interventions targetting risk factor reduction increases over a 30-year time horizon and the benefit is potentially higher in ethnic groups with higher risk factor prevalence. HIGHLIGHTS: Achievable risk factor reductions have significant prevention potential. The projected impact of risk factor interventions increase with time. We need to consider longer time horizons when assessing proposed interventions.