Background: Global population ageing has contributed to attendant increased incidence of cognitive dysfunction and neurodegenerative processes. Deficits in executive functioning specifically may significantly impair independent functioning. The current study investigated health and lifestyle factors later in life that are associated with executive abilities. A further aim of the current study was to expand on the previous uses of a new measure of executive functioning specially designed for older adults: the California Older Adult Stroop Test (COAST).
Method: The data for this project were collected as part of the Longitudinal Assessment of Women (LAW) study, established to investigate physical and cognitive changes in women aged 40 to 80 years. A comprehensive neuropsychological test battery, augmented by self-report data from a postal survey, for 376 LAW study participants was analysed. Measures included cognitive, psychiatric, and lifestyle factors, the latter including alcohol intake and BMI, in addition to standard sociodemographic indicators.
Results: Strong correlations were observed between the COAST – Colour Word test time and D-KEFS Trail Making Test – number letter switching, r(359) = .60, p < .01, D-KEFS Verbal Fluency – total responses, r(357) = -.51, p < .01 and medium correlations with D-KEFS Verbal Fluency – category switching accuracy, r(358) = -.45, p < .01 and D-KEFS Tower Test – Total achievement score, r (359)= -.32, p < .01. Error measures from the COAST Colour Word trial demonstrated adequate correlations with most error measures from these tests (rs = .14 - .35). Investigation of variables influencing executive functioning reflected in composite measures (with and without error measures included) demonstrated that age, education, self-reported depression, BMI and alcohol use significantly predicted performance. Increasing age and higher self-reported depression scores were established as having a negative relationship with executive abilities while higher levels of education, mild alcohol consumption and higher BMI were observed to have a positive relationship with executive functioning. Social support, self-reported anxiety, hypertension, diabetes and smoking failed significantly to contribute to regression models predicting executive functioning performance: methodological limitations of the current study may have contributed to these findings.
Conclusions: The COAST compares favourably to other well established measures of executive functioning. These results suggest the COAST is a useful measure for the assessment of executive functioning in older adults. The data reported here on the relationship between health and lifestyle factors and executive functioning in the face of advancing age suggest that treating depression, encouraging some mild alcohol use and promoting appropriate diet (to retain a healthy BMI) would be important intervention strategies. As the data were obtained on an exclusively female population, these findings remain to be confirmed in mid-aged and older men. While age is an inevitable risk factor in cognitive decline in later life, several modifiable lifestyle factors may serve to protect against excess decline in executive functioning in later life.