Risk profiles for mild cognitive impairment vary by age and sex: The Sydney memory and ageing study

OBJECTIVES: To examine age- and sex-related differences in risk and protective factors for mild cognitive impairment (MCI) in community-based elderly individuals. DESIGN: Cross-sectional study. SETTING: The population-based Sydney Memory and Ageing Study. PARTICIPANTS: A total of 757 nondemented, community-dwelling elderly individuals from an English-speaking background categorized as younger (70-79 years) or older (80-90 years). MEASUREMENTS: Risk of MCI was determined for sociodemographic, lifestyle, and cardiac, physical, mental, and general health factors using age- (and sex-) adjusted multiple regressions comprising initially significant univariate factors. RESULTS: The point prevalence of MCI within our sample was 39.1% overall: it was lowest in younger women (32.3%) and similar across men and older women (41.9%-43.6%). The risk of MCI across all participants was increased by the APOE ε4 allele, high homocysteine, and heart disease; and decreased by better odor identification, visual acuity, and mental activity. Risk factors in all younger participants were slow 6-m walk, poor odor identification, and high homocysteine. Risk of MCI was associated in younger women with history of depression, less mental activity, slower 6-m walk, poorer visual acuity, and higher homocysteine; and in younger men with poorer odor identification and higher homocysteine. Older participants showed no significant risk factors for MCI, except for poorer visual acuity in men. Supporting these findings were statistically significant interactions that reflected the differences in risk factor profiles between age and/or sex groups. CONCLUSIONS: Risk factors for MCI differ in men and women and vary with age. This has implications for preventing MCI and possibly dementia.