INTRODUCTION

We aimed to calculate population attributable fractions (PAFs) for incident dementia and examine sex differences in individuals with no cognitive impairment (NCI) or mild cognitive impairment (MCI).

METHODS

Longitudinal data from the Rush University Memory and Aging Project (MAP) were analyzed. Cox proportional-hazards models were used to estimate covariate-adjusted hazard ratios for incident dementia and calculate weighted PAFs within each cognitive status/sex subgroup.

RESULTS

The analytical sample comprised 1481 NCI (76.7% female) and 515 MCI (69.7% female) participants. Overall PAFs were similar for NCI (18.2%) and MCI (18.6%) subgroups, however, sex differences were evident. Males had higher PAFs than females in both NCI (42.5% vs. 25.1%) and MCI (51.5% vs. 12.4%), with differing risk factor profiles.

DISCUSSION

These findings support the notion that dementia risk is modifiable after the onset of MCI and that the number of potentially preventable dementia cases may be higher in males than in females.

HIGHLIGHTS

The proportion of potentially preventable dementia cases was similar for no cognitive impairment (NCI) and mild cognitive impairment (MCI) individuals. For both cognitive states, a higher proportion of potentially preventable dementia cases was observed in males compared to females. The profiles of modifiable risk factors contributing to dementia differed between males and females. Lifestyle related risk factors were more prominent contributors to preventable dementia in males. Psychosocial risk factors, such as depression and social isolation, were important contributors in females.