Generational differences in cognitive function in middle‐aged to older adults

Background Cognitive impairment and dementia are major health concerns. While the number of cases is expected to increase with the aging populations, recent research shows that age‐specific dementia prevalence rates are declining. This may be due to reduced risks of cardiovascular and metabolic diseases and harmful environmental exposures and healthier lifestyles. Given the decades‐long preclinical phase of dementia, detection of early cognitive changes might improve future treatment and prevention methods. However, research on generational differences in cognitive function in middle‐aged to older adults is limited. The aim of this study was to determine whether individuals from more recent generations show better cognitive function. Method This cross‐sectional study is based on data from 4439 participants from the Epidemiology of Hearing Loss Study (EHLS) and Beaver Dam Offspring Study (BOSS), two studies of adults in Beaver Dam, Wisconsin. Each participant’s birth year was used to assign a birth cohort (1901‐1924: Greatest Generation; 1925‐1945: Silent Generation; 1946‐1964: Baby Boom Generation; 1965‐1984: Generation X). Cognitive function was assessed by Trail‐making Test A and B (TMTA, TMTB). We used multivariable linear regression models adjusted for age and sex to determine birth cohort (generational) differences in TMT performance. We repeated models adjusting for education. Result In preliminary analyses, TMTA performance was better in more recent generations as compared to the Greatest Generation (Silent: ‐26.88 seconds (s); 95 % confidence interval (CI) ‐30.60,‐23.15; Baby Boom: ‐25.70s; 95% CI ‐30.64,‐20.77; Generation X: ‐17.82s; 95% CI ‐24.37,‐11.27). Performance on TMTB showed larger generational differences as compared to the Greatest Generation: Silent: ‐50.04s; 95% CI ‐58.11,‐41.97; Baby Boom: ‐63.38s; 95% CI ‐73.83,‐52.93; Generation X: ‐43.53s; 95% CI ‐57.23,‐29.83. Although education levels differed by generation, including education did not change these patterns. Conclusion This study suggests better processing speed and executive function performance among more recent generations even when adjusting for educational levels. This implies that future burdens of cognitive decline and dementia may be lower than currently estimated. The difference also suggests that there are modifiable risk factors that may help to explain the etiology of cognitive decline and provide potential pathways for healthy brain aging and prevention of Alzheimer’