Cognitive decline, or the weakening of our ability to think, learn, pay attention, remember, or reason, over time can be predicted by certain health risks present in later life. Hypertension, diabetes, depressive symptoms, and smoking are all known predictors. Current research has not shown how these risk factors affect cognition in midlife and if there are differing results between racial groups. A better understanding of how these risk factors influence cognition in midlife could lead to more effective and timely health interventions.
Data from the large epidemiological Study of Women’s Health Across the Nation (SWAN) was used by PhD candidate Jasmine Dixon and her team to examine risk factors for decline in episodic memory, processing speed, and working memory in midlife women. These risk factors were also analyzed to see if a person’s race played a role in what areas of cognition changed.
Women who identified as African American, Asian American, and European American women age 42-52 participated in the study. Once per year, participants completed questionnaires to assess depressive symptoms, family income, age, and physical health. Measures of hypertension, diabetes, smoking, and depressive symptoms were collected, and cognitive tests were administered.
The findings, to be published in Neuropsychology, showed at baseline that African Americans had poorer results of the three cognitive measures, and greater episodic memory decline compared to European Americans. Asian Americans had poorer episodic memory and working memory, but better processing speed than European Americans.
It is of note that the researchers determined not all of these risk factors linked to cognitive decline in late life were related to cognitive changes during midlife. There wasn’t significant evidence of cognitive decline in midlife. However, the researchers uncovered some close associations between risk factors in midlife and cognitive outcomes.
“Depressive symptoms were associated with poorer episodic memory and processing speed at baseline; further, diabetes was associated with poorer processing speed at baseline,” the paper states. Also, the greater a person’s depressive symptoms, the poorer their episodic memory was at baseline for African Americans but not European Americans. There were no significant results when hypertension or smoking were analyzed.
Results connected with the “cumulative disadvantage theory” hypothesizing that multiple stressors accumulate over the lifespan in racial and ethnic minority populations, resulting in increasing health disparities relative to the majority population. For African Americans chronic adversity due to racism and discrimination puts this population at disadvantages to European Americans. This systemic adversity across the lifespan may make African Americans more vulnerable to risk factors of poor cognition.
Dixon relates, "It is important to understand racial disparities in order to better develop interventions that are relevant to specific populations. A more tailored approach rather than a universal approach to addressing cognitive health is more appropriate and necessary because of these known disparities. I hope this study highlights that when addressing cognitive health there needs to be a lifespan approach, not just addressing cognition during later life."