3 Does External Locus of Control Moderate the Intergenerational Transmission of Dementia Risk Among Non-Latinx Black and Non-Latinx White Middle-Aged Adults?

Abstract

Objective:

People whose parents had dementia or memory impairment are at higher risk for later-life cognitive impairment themselves. One goal of our research is to identify factors that either increase the risk of or protect against family history of dementia over the life course. External locus of control has been associated with lower cognitive function in middle-aged and older adults. Previous findings have shown that adults racialized as Black have relatively high levels of external locus of control due to inequity and racism. We hypothesized that lower parental memory would be associated with lower offspring memory among Non-Latinx Black and Non-Latinx White (hereafter Black and White, respectively) adults; and associations would be stronger among participants with higher levels of external locus of control.

Participants and Methods:

Participants comprised 594 adults racialized as Black or White (60.3% Black; 62% women; aged 56.1 ± 10.4; 15.3 ± 2.7 years of education) from the Offspring Study who are the adult children of participants in the Washington Heights Inwood Columbia Aging Project (WHICAP). Parental memory was residualized for age (74.3 ± 6.0) and education (13.7 ± 3.1). Self-reported external locus of control was assessed using 8 items from the the perceived control questionnaire. Memory was assessed with the Selective Reminding Test, and a composite of total and delayed recall scores were computed. Linear regression quantified the interaction between parental memory and external locus of control on memory in models stratified by race, and adjusted for age, sex/gender, and number of chronic health diseases.

Results:

Among Black participants (n=358), there were no main effects of parental memory or locus of control on offspring memory. However, lower parental memory was associated with lower offspring memory among Black participants with high levels of external locus of control (standardized estimate=0.36, p=0.02, 95%CI [0.05, 0.67]). Associations were attenuated and non-significant at lower levels of control. Among White participants (n=236), there was a main effect of parental memory on offspring memory, and this association did not vary by levels of external locus of control.

Conclusions:

Poor parental memory, which reflects risk for later-life cognitive impairment and dementia, was associated with lower memory performance among White middle-aged participants. Among Black participants, this association was observed among those with high levels of external locus of control only. Economic and social constraints shape levels of external locus of control and are disproportionately experienced by Black adults. In the face of greater external locus of control, a cascade of psychological and biological stress-related processes may be triggered and make Black adults’ memory function more vulnerable to the detrimental impact of parent-related dementia risk. Longitudinal analyses are needed to clarify temporal associations. Nonetheless, these findings suggest that reducing social and economic inequities disproportionately experienced by Black adults may dampen the effect of intergenerational transmission of dementia risk on cognition.