Socioeconomic position, modifiable dementia risk and cognitive decline: results of 12-year Maastricht Aging Study.

Abstract

This study investigated whether the association between modifiable dementia risk and rate of cognitive decline differs across socioeconomic status (SES) strata. Data were used from Maastricht Aging Study, a prospective cohort study with a 12-year follow-up. The baseline sample consisted of 1023 adults over 40 years old. The "LIfestyle for BRAin health" (LIBRA) index was used to assess modifiable dementia risk. Cognitive performance was assessed at baseline, 6 and 12 years, and measured in the domains of information processing speed, executive functioning and verbal memory function. An SES score was calculated from equivalent income and educational level (tertiles). Linear mixed models were used to study the association between LIBRA, SES and their interaction on the rate of cognitive decline. Participants in the lowest SES tertile displayed more decline in information processing speed (vs. middle SES: X2 = 7.08, P = 0.029; vs. high SES: X2 = 9.49, P = 0.009) and verbal memory (vs. middle SES: X2 = 9.28, P < 0.001; vs. high SES: X2 = 16.68, P < 0.001) over 6 years compared to their middle- and high-SES counterparts. Higher (unhealthier) LIBRA scores were associated with more decline in information processing speed (X2 = 12.66, P = 0.002) over 12 years and verbal memory (X2 = 4.63, P = 0.032) over 6 years. No consistent effect modification by SES on the association between LIBRA and cognition was found. Results suggest that lifestyle is an important determinant of cognitive decline across SES groups. Yet, people with low SES had a more unfavorable modifiable risk score suggesting more potential for lifestyle-based interventions.