Birth in High Infant Mortality States and Dementia Risk in a Cohort of Elderly African American and White Health Care Members

Maternal separation differentially modulates early pathology by sex in 5xFAD Alzheimer's disease-transgenic mice

Alzheimer's disease (AD) is the most common neurodegenerative disease. Most cases of AD are considered idiopathic and likely due to a combination of genetic, environmental, and lifestyle-related risk factors. Despite occurring decades before the typical age of an AD diagnosis, early-life stress (ELS) has been suggested to have long-lasting effects that may contribute to AD risk and pathogenesis. Still, the mechanisms that underlie the role of ELS on AD risk remain largely unknown. Here, we used 5xFAD transgenic mice to study relatively short-term alterations related to ELS in an AD-like susceptible mouse model at 6 weeks of age. To model ELS, we separated pups from their dams for 3 h per day from postnatal day 2-14. Around 6 weeks of age, we found that maternally separated (MS) 5xFAD mice, particularly female mice, displayed increased amyloid-β-immunoreactivity in the anterior cingulate cortex (ACC) and basolateral amygdala (BLA). In anterior cingulate cortex, we also noted significantly increased intraneuronal amyloid-β-immunoreactivity associated with MS but only in female mice. Moreover, IBA1-positive DAPI density was significantly increased in relation to MS in ACC and BLA, and microglia in BLA of MS mice had significantly different morphology compared to microglia in non-MS 5xFAD mice. Cytokine analysis showed that male MS mice, specifically, had increased levels of neuroinflammatory markers CXCL1 and IL-10 in hippocampal extracts compared to non-MS counterparts. Additionally, hippocampal extracts from both male and female MS 5xFAD mice had decreased levels of synapse- and activity-related markers Bdnf, 5htr6, Cox2, and Syp in hippocampus. Lastly, we performed behavioral tests to evaluate anxiety- and depressive-like behavior and working memory but could not detect any significant differences between groups. Overall, we detected several sex-specific molecular and cellular alterations in 6-week-old adolescent 5xFAD mice associated with MS that may help explain the connection between ELS and AD risk.

Do prenatal factors shape the risk for dementia?: A systematic review of the epidemiological evidence for the prenatal origins of dementia

PURPOSE

Prenatal factors such as maternal stress, infection and nutrition affect fetal brain development and may also influence later risk for dementia. The purpose of this systematic review was to provide an overview of all studies which investigated the association between prenatal factors and later risk for dementia.

METHODS

We systematically searched MEDLINE and Embase for original human studies reporting on associations between prenatal factors and dementia from inception to 23 November 2022. Prenatal factors could be any factor assessed during pregnancy, at birth or postnatally, provided they were indicative of a prenatal exposure. Risk of bias was assessed using the Newcastle Ottawa Scale. We followed PRISMA guidelines for reporting.

RESULTS

A total of 68 studies met eligibility criteria (including millions of individuals), assessing maternal age (N = 30), paternal age (N = 22), birth order (N = 15), season of birth (N = 16), place of birth (N = 13), prenatal influenza pandemic (N = 1) or Chinese famine exposure (N = 1), birth characteristics (N = 3) and prenatal hormone exposure (N = 4). We observed consistent results for birth in a generally less optimal environment (e.g. high infant mortality area) being associated with higher dementia risk. Lower and higher birth weight and prenatal famine exposure were associated with higher dementia risk. The studies on season of birth, digit ratio, prenatal influenza pandemic exposure, parental age and birth order showed inconsistent results and were hampered by relatively high risk of bias.

CONCLUSION

Our findings suggest that some prenatal factors, especially those related to a suboptimal prenatal environment, are associated with an increased dementia risk. As these associations may be confounded by factors such as parental socioeconomic status, more research is needed to examine the potential causal role of the prenatal environment in dementia.

Exposure to the Dutch Famine in Early Gestation and Cognitive Function and Decline in Older Age

People exposed to the 1944-1945 Dutch famine in early gestation performed worse on a selective attention task at age 58 and reported more cognitive problems at age 72. We here hypothesized that undernutrition in early gestation is associated with poorer cognitive functioning in older age and a higher rate of cognitive decline. We tested this hypothesis in the Dutch famine birth cohort in men and women combined and separately. We assessed cognitive function using a Stroop-like, trail-making and 15-word task (at ages 68 and 74) and the Montreal cognitive assessment as well as self-perceived cognitive problems (at age 74) in 73 men (n = 34) and women (n = 39). We compared cognitive function and decline (change in cognitive function between age 68 and 74) between those exposed in early gestation and those not exposed (born before or conceived after the famine). Although in both men and women cognitive function declined from age 68 to 74, cognitive task scores and the rate of decline did not differ between those exposed or unexposed to famine. At age 74, men exposed to famine in early gestation more often reported cognitive problems, although this was not statistically different from unexposed men (OR 3.1 [95%CI 0.7 to 13.0]). We did not find evidence of increased cognitive decline after prenatal undernutrition. Selective participation and mortality may have hampered our ability to detect potential true effects. The self-perceived cognitive problems among men who had been exposed to famine in early gestation might be an indication of future dementia risk.

Area-Level Infant Mortality Exposure in Early Life and Alzheimer's Disease Mortality: Examining Variation Based on Age, Sex, and Place of Birth

BACKGROUND

Growing evidence suggests that critical periods in early life may contribute to one's risk of Alzheimer's disease and related dementias (ADRD) in later life. In this paper we explore the role that exposure to infant mortality plays in later life ADRD.

OBJECTIVE

To determine if exposure to early life infant mortality is associated with later mortality from ADRD. Also, we explore how these associations differ by sex and age group, along with the role of state of birth and competing risks of death.

METHODS

We use a sample of over 400,000 individuals aged 50 and above with the NIH-AARP Diet and Health Study with mortality follow-up, allowing us to examine how early life infant mortality rates along with other risk factors play in one's individual mortality risk.

RESULTS

We show that infant mortality rates are associated with death from ADRD among those under 65 years of age, but not those over 65 at baseline interview. Moreover, when factoring in competing risks of death, the associations are relatively unchanged.

CONCLUSION

These results suggest that those exposed to worse adverse conditions during critical periods increase their likelihood of death from ADRD earlier than average, due to that exposure increasing their susceptibility to develop illness later on in life.

Race, Childhood Socioeconomic Status, and Region of Childhood Residence as Intersectional Life Course Predictors of Cognitive Aging in the U.S

Background and Objectives

Race, childhood socioeconomic status (cSES), and region of childhood residence are each associated with later life cognition, but no studies have examined how the confluence of these factors influence later life cognitive performance. Guided by intersectionality theory, we examined individuals’ social positionality across these dimensions as a predictor of cognitive performance in later life among non-Hispanic White (NHW) and Black (NHB) older adults.

Research Design and Methods

We used data from the 2010-2016 waves of the Health and Retirement Study (HRS) with participants ages 65 and older in 2010. We employed growth curve modeling to estimate associations among race, cSES and region of childhood residence, as well as their interactions, and cognitive performance at baseline and over time.

Results

Identifying as NHB, residing in the South, and having lower cSES each were associated with poorer later life cognition at baseline. Childhood residence in the South was an especially strong risk factor for poorer cognition among NHBs. Among NHWs, higher cSES was associated with better baseline cognitive performance, especially among those from the South. NHBs from the South demonstrated a small advantage of higher cSES, but regardless of cSES, NHBs from the South had lower levels of baseline cognitive scores compared to all other subgroups. We found that Southern childhood residence predicted faster rates of change in over a 6-year period.

Discussion and Implications

Our findings suggest that intersectional social positions across race, cSES, and region of childhood residence primarily influence baseline cognition in later life. Results implicate the importance of attention to multiple social positions in the context of racism within social policies and other initiatives to promote equity in life course brain health.

Can healthy lifestyle reduce disease progression of Alzheimer's during a global pandemic of COVID-19?

The novel coronavirus disease 2019 (COVID-19) has pushed the medical system to its breaking point. While the virus does not discriminate, the elderly and those with comorbidities, including hypertension severe obesity, diabetes mellitus, coronary disease, pneumonia and dementia, are at a greater risk for adverse outcomes due to COVID-19. While many people navigate their new normal, the question of what the long-lasting effects of the pandemic may be, lingers. To investigate how vulnerable populations are affected by the pandemic, we focused on Alzheimer's disease, a vector to understanding how the virus has impacted AD progression and risk via aging. By assessing the effect of COVID-19 on AD patients, we explore genetics, metabolism, and lifestyle factors in both COVID-19 and Alzheimer's disease that can work synergistically to precipitate adverse outcomes. This article also discusses how age-related conditions and/or age-related comorbidities susceptible to COVID-19. We also discuss possible healthy lifestyle factors reduce and/or combat COVID-19 now and in the future.

Lifecourse socioeconomic changes and late-life cognition in a cohort of U.S.-born and U.S. immigrants: findings from the KHANDLE study

BACKGROUND

Low socioeconomic status (SES) in early and late life has been associated with lower late-life cognition. Less is known about how changes in SES from childhood to late life are associated with late-life cognition, especially among diverse populations of older adults.

METHODS

In a multi-ethnic sample (n = 1353) of older adults, we used linear regression to test associations of change in comprehensive measures of SES (financial, cultural, and social domains) from childhood to late life with semantic memory, episodic memory, and executive function. We tested whether the association between SES trajectory and late-life cognition differed by populations who resided in the U.S. during childhood or immigrated to the U.S. as adults.

RESULTS

Participants with low childhood/high late-life financial capital had better semantic memory (β = 0.18; 95% CI: 0.04, 0.32) versus those with low financial capital in both childhood and late life, regardless of childhood residence. We observed a significant interaction in the association of verbal episodic memory and cultural capital by childhood residence (p = 0.08). Participants with a foreign childhood residence had higher verbal episodic memory if they had low childhood/high late-life cultural capital (β = 0.32; 95% CI: 0.01, 0.63), but lower verbal episodic memory if they had high childhood/low late-life cultural capital (β = - 0.40; 95% CI: - 0.94, 0.13). Having high lifecourse social capital was associated with better verbal episodic memory scores among those with a U.S. childhood (β = 0.34; 95% CI: 0.14, 0.55), but lower verbal episodic memory among those with a foreign childhood (β = - 0.10; 95% CI: - 0.51, 0.31).

CONCLUSIONS

High financial and cultural capital in late life is associated with better cognition, regardless of early childhood SES or childhood residence.

Alzheimer's Disease and Alzheimer's Disease-Related Dementias in Older African American and White Veterans

BACKGROUND

Racial disparity in the epidemiology of Alzheimer's disease and Alzheimer's disease-related dementias (AD/ADRD) has been reported. However, less is known about this disparity among Veterans.

OBJECTIVE

To estimate the racial disparity in AD/ADRD among the Veterans.

METHODS

Of the 5,413,418 Veterans≥65 years receiving care at the Veterans Health Administration (1999-2016), 4,045,269 were free of prevalent AD/ADRD, schizophrenia, or bipolar disorder at baseline. Of these, 432,469 were African American. Race was self-identified and incident AD/ADRD during 20 (median 6.7) years of follow-up was ascertained using International Classification of Diseases codes.

RESULTS

Patients had a mean age of 70.4 (±6.6) years and 97.8% were men. Age-sex-adjusted incidence of AD/ADRD per 1,000 person-year was 19.3 and 10.8 for African American and white Veterans, respectively (age-sex-adjusted hazard ratio associated with African American race, 1.77; 95% confidence interval, 1.75-1.79; p < 0.0001). This association remained essentially unchanged after multivariable adjustment (hazard ratio, 1.67; 95% confidence interval, 1.65-1.69; p < 0.0001). Among the key baseline characteristics that were significant predictors of AD/ADRD in both races, stroke was a significantly stronger predictor among African Americans, and Hispanic ethnicity and depression among whites (p-value for all interaction,<0.0001).

CONCLUSION

The findings of a higher incidence of AD/ADRD among African American Veterans is consistent with the findings in the general population reported in the literature, although the overall incidence appears to be lower than that in the general population. Future studies need to examine this disparity in incidence as well as the between-race heterogeneity in AD/ADRD risk.

Neurologic Complications of Poverty: the Associations Between Poverty as a Social Determinant of Health and Adverse Neurologic Outcomes

PURPOSE OF REVIEW

Increasing attention has been paid in recent decades to social determinants of health as a risk factor for disease development and disease severity. While traditionally heart disease, family history, lipid profile, and tobacco use have all been associated with increased risk of neurological disease, numerous studies now show that the influence of poverty may be just as strong a risk factor. This study summarizes the recent literature on poverty as it contributes to neurological disease.

RECENT FINDINGS

Children growing up in poverty have increased risk for cognitive deficits and behavioral disorders as reported by Noble et al. (Dev Sci. 9(6):642-54, 2006) and Farah et al. (Brain Res. 1110(1):166-74, 2006) as well as worse outcomes when it comes to epilepsy management and disease course as discussed by Camfield et al. (Epilepsia. 57(11):1826-33, 2016). In adulthood, as the number of social determinants of health increases, the incidence of stroke and severe stroke increases significantly as reported by Reshetnyak et al. (Stroke. 51:2445-53, 2020) as does exposure to neurologically significant infectious diseases and incidence of dementia as reported by Sumilo et al. (Rev Med Virol. 18(2):81-95, 2008) and Zuelsdorff et al. (Alzheimer's Dement. 6(1):e12039, 2020). Social determinants of health including poverty should be considered a risk factor for disease. More attention is needed from clinicians as well as from a public health perspective to address this disparity.

Educational Benefits and Cognitive Health Life Expectancies: Racial/Ethnic, Nativity, and Gender Disparities

BACKGROUND AND OBJECTIVES

To examine racial/ethnic, nativity, and gender differences in the benefits of educational attainment on cognitive health life expectancies among older adults in the United States.

RESEARCH DESIGN AND METHODS

We used data from the Health and Retirement Study (1998-2014) to estimate Sullivan-based life tables of cognitively healthy, cognitively impaired/no dementia, and dementia life expectancies by gender for older White, Black, U.S.-born Hispanic, and foreign-born Hispanic adults with less than high school, high school, and some college or more.

RESULTS

White respondents lived a greater percentage of their remaining lives cognitively healthy than their minority Black or Hispanic counterparts, regardless of level of education. Among respondents with some college or more, versus less than high school, Black and U.S.-born Hispanic women exhibited the greatest increase (both 37 percentage points higher) in the proportion of total life expectancy spent cognitively healthy; whereas White women had the smallest increase (17 percentage points higher). For men, the difference between respondents with some college or more, versus less than high school, was greatest for Black men (35 percentage points higher) and was lowest for U.S.-born Hispanic men (21 percentage points higher).

DISCUSSION AND IMPLICATIONS

Our results provide evidence that the benefits of education on cognitive health life expectancies are largest for Black men and women and U.S.-born Hispanic women. The combination of extended longevity and rising prevalence of Alzheimer's disease points to the need for understanding why certain individuals spend an extended period of their lives with poor cognitive health.