Abstract
INTRODUCTION: It is unknown in which, if any, subgroups of older adults multidomain interventions are effective at reducing long-term dementia incidence. METHODS: We pooled up to 12 years of follow-up data from 5205 participants aged > 70 from the Multidomain Alzheimer Preventive Trial (MAPT) and Prevention of Dementia by Intensive Vascular Care (preDIVA) studies. The primary outcome was incident all-cause dementia. Pre-specified subgroups were defined by dementia risk factors (age, sex, education, apolipoprotein E [APOE] genotype, cognitive status, and cardiovascular risk factors). RESULTS: Four hundred eighty-six participants developed dementia during 37,782 person-years of follow-up. Higher incidence was associated with baseline age, APOE ε4 genotype, physical inactivity, Mini-Mental State Examination, and blood pressure. Multidomain intervention had no effect on incident dementia overall (hazard ratio = 0.98, 95% confidence interval 0.80-1.21), or in any pre-specified subgroup. A recursive partitioning algorithm also did not detect any subgroups, defined by single or multiple risk factors, showing a differential intervention effect. DISCUSSION: We did not identify any subgroups of older adults in whom multidomain interventions significantly reduced incident dementia. CLINICAL TRIAL REGISTRATION: MAPT: NCT00672685 (clinicaltrials.gov); PreDIVA: ISRCTN29711771 (ISRCTN registry) HIGHLIGHTS: We pooled up to 12 years of follow-up data from two multidomain prevention trials. Five thousand two hundred five participants aged ≥ 70 were included. Subgroups were pre-defined by modifiable and non-modifiable dementia risk factors. A data-driven recursive partitioning algorithm was also used. Multidomain intervention did not lower incident dementia overall or in any subgroup.