Cognitive reserve over life course and 7-year trajectories of cognitive decline: results from China health and retirement longitudinal study

Background: Cognitive reserve (CR) could partly explain the individual heterogeneity in cognitive decline. No study measured CR from a life course perspective and investigated the association between CR and trajectories of cognitive decline in older Chinese adults. / Methods: Data of 6795 Chinese adults aged 60+ from China Health and Retirement Longitudinal Study were used. Global cognition score (0–32) was assessed in all four waves. A life-course CR score was constructed using markers of childhood circumstance, education, highest occupational class, and leisure activities in later life. Latent growth curve modelling (LGCM) was applied to assess the association between CR and trajectories of cognitive decline. / Results: For the life-course CR, factor loadings of markers in adulthood and later life were larger than that of markers in childhood. The life-course CR score (ranged between − 2.727 and 6.537, SD: 1.74) was higher in urban Chinese adults (0.75, SD: 1.90) than in rural Chinese adults (− 0.50, SD: 1.43). The unconditional LGCM results showed that urban older Chinese adults had better global cognition at baseline (intercept: 15.010, 95% CI: 14.783, 15.237) and a slower rate of cognitive decline per year (linear slope: -0.394, 95% CI: − 0.508, − 0.281) than their rural counterparts (intercept: 12.144, 95% CI: 11.960, 12.329; linear slope: -0.498, 95% CI: − 0.588, − 0.408). After controlling for all covariates, one-unit higher CR score was associated with 1.615 (95% CI: 1.521, 1.709) and 1.768 (95% CI: 1.659, 1.876) unit higher global cognition at baseline for urban and rural older Chinese adults, respectively. The slower rate of cognitive decline associated with higher CR was more evident in rural residents (slope: 0.083, 95% CI: 0.057, 0.108) than in their urban counterparts (0.054, 95% CI: 0.031, 0.077). / Conclusions: CR was associated with better baseline cognition and slower cognitive decline in Chinese older adults. Although rural residents were disadvantaged in both CR and cognition, the protective effect of CR against cognitive decline was stronger for them than in those who live in urban area

The mental and physical health of young carers: a systematic review

The health of those who care for someone with a health condition or advanced age is poorer, on average, than non-carers. However, the health of young carers (<18 years of age) has been under-researched, especially in quantitative studies. This systematic review aimed to summarise studies assessing the mental and physical health of young carers. 1162 unique studies were screened and 14 associations between being a young carer and health were identified (two studies were treated as a single unit of analysis as they had information from the same sample). Most of the included studies were done in the UK, with the remaining studies done in the USA, Canada, Australia, and Austria. A cross-European study of 21 countries was also included. Five of the included studies investigated both mental and physical health outcomes, seven studies investigated only mental health outcomes, and one study investigated only physical health outcomes of being a young carer. All of the included studies, except one, were cross-sectional in design. Most studies found that young carers had poorer physical and mental health, on average, than their non-caregiving peers. However, the evidence is relatively weak and more quantitative research is needed, particularly research that is longitudinal in design and assesses physical health outcomes

Bidirectional association between depressive symptoms and mild cognitive impairment over 20 years: Evidence from the health and retirement study in the United States

BACKGROUND: Research examining the association between depressive symptoms and mild cognitive impairment (MCI) has yielded conflicting results. This study aimed to examine the bidirectional association between depressive symptoms and MCI, and the extent to which this bidirectional association is moderated by gender and education. METHODS: Data come from the US Health and Retirement Study over a 20-year period (older adults aged ≥50 years). Competing-risks regression is employed to examine the association between baseline high-risk depressive symptoms and subsequent MCI (N = 9317), and baseline MCI and subsequent high-risk depressive symptoms (N = 9428). Interactions of baseline exposures with gender and education are tested. RESULTS: After full adjustment, baseline high-risk depressive symptoms were significantly associated with subsequent MCI (SHR = 1.20, 95%CI 1.08–1.34). Participants with baseline MCI are more likely to develop subsequent high-risk depressive symptoms than those without baseline MCI (SHR = 1.16, 95%CI 1.01–1.33). Although gender and education are risk factors for subsequent depression and MCI, neither moderates the bidirectional association. LIMITATIONS: Items used to construct the composite cognitive measure are limited; selection bias due to missing data; and residual confounding. CONCLUSIONS: Our study found a bidirectional association between depressive symptoms and MCI. High-risk depressive symptoms are related to a higher risk of subsequent MCI; and MCI predicts subsequent high-risk depression. Though neither gender nor education moderated the bidirectional association, public health interventions crafted to reduce the risk of depression and MCI should pivot attention to older women and those with less formal education

The Association between Subjective Cognitive Decline and Trajectories of Objective Cognitive Decline: Do Social Relationships Matter?

Objectives : We examine the association between subjective cognitive decline (SCD) and the trajectories of objective cognitive decline (OCD); and the extent to which this association is moderated by social relationships. Methods : Data come from waves 10 (2010) through 14 (2018) of the Health and Retirement Study, a nationally representative panel survey of individuals aged 50 and above in the United States. OCD is measured using episodic memory, and overall cognition. SCD is assessed using a baseline measure of self-rated memory. Social relationships are measured by social network size and perceived positive and negative social support. Growth curve models estimate the longitudinal link between SCD and subsequent OCD trajectories and the interactions between SCD and social relationship variables on OCD. Results : SCD is associated with subsequent OCD. A wider social network and lower perceived negative support are linked to slower decline in memory, and overall cognition. None of the social relationship variables, however, moderate the link between SCD and future OCD. Conclusion : Knowing that SCD is linked to subsequent OCD is useful because at SCD stage, deficits are more manageable relative to those at subsequent stages of OCD. Future work on SCD and OCD should consider additional dimensions of social relationships

Does providing informal care in young adulthood impact educational attainment and employment in the UK?

Most research on the effects of caring has focused on older spouses or working-age carers providing care for older people, but providing care in early adulthood may have longer-term consequences, given the importance of this life stage for educational and employment transitions. This study aims to investigate the impact of informal care in early adulthood on educational attainment and employment in the UK and to test whether these associations differ by gender or socio-economic circumstances. Data are from young adults (age 16–29 at first interview, n = 27,209) in the UK Household Longitudinal Study wave 1 (2009/11) to wave 10 (2018/2020). Carers are those who provide informal care either inside or outside the household. We also considered six additional aspects of caring, including weekly hours spent caring, number of people cared for, relationship to care recipient, place of care, age at which caring is first observed, and duration of care. Cox regression was used to analyse the association between caring and educational qualifications and employment transitions. We found that young adult carers were less likely to obtain a university degree and enter employment compared to young adults who did not provide care. In terms of care characteristics, weekly hours spent caring were negatively associated with the likelihood of obtaining a university degree qualification and being employed. Providing care after full-time education age negatively influenced employment entry, but having a university degree buffered the negative influence of providing care on entering employment. The influence on unemployment may be stronger for female carers than for male carers. Our results highlight the importance of supporting the needs of young adults who are providing informal care while making key life course transitions

Detecting Thermal Cloaks via Transient Effects

Recent research on the development of a thermal cloak has concentrated on engineering an inhomogeneous thermal conductivity and an approximate, homogeneous volumetric heat capacity. While the perfect cloak of inhomogeneous κ and inhomogeneous ρcp is known to be exact (no signals scattering and only mean values penetrating to the cloak’s interior), the sensitivity of diffusive cloaks to defects and approximations has not been analyzed. We analytically demonstrate that these approximate cloaks are detectable. Although they work as perfect cloaks in the steady-state, their transient (time-dependent) response is imperfect and a small amount of heat is scattered. This is sufficient to determine the presence of a cloak and any heat source it contains, but the material composition hidden within the cloak is not detectable in practice. To demonstrate the feasibility of this technique, we constructed a cloak with similar approximation and directly detected its presence using these transient temperature deviations outside the cloak. Due to limitations in the range of experimentally accessible volumetric specific heats, our detection scheme should allow us to find any realizable cloak, assuming a sufficiently large temperature difference

Does providing informal care in young adulthood impact educational attainment and employment? Evidence from the UK Household Longitudinal Study

Most research on the effects of caring has focused on older spouses or working-age carers providing care for older people, but providing care in early adulthood may have longer-term consequences given the importance of this life stage for educational and employment transitions. This study aims to investigate the impact of informal care in early adulthood on educational attainment and employment in the UK, and to test whether these associations differ by gender or socioeconomic circumstances. Data are from young adults (age 16-29 at first interview, n=27,209) in the UK Household Longitudinal Study wave 1 (2009/11) to wave 10 (2018/2020). Carers are those who provide informal care either inside or outside household. We also considered six additional aspects of caring, including weekly hours spent caring, number of people cared for, relationship to care recipient, place of care, age at which caring is first observed, and duration of care. Logistic regression was used to analyse the association with educational qualifications. Cox regression was used to analyse the association with employment transitions, and piecewise models were used to disentangle the short and long-term effects of caring on employment amongst carers. We found that young adult carers were less likely to obtain a university degree and to enter employment, and more likely to enter unemployment and exit from paid employment, compared to young adults who did not provide care. Caring in young adulthood may influence employment both immediately and in the longer term. In terms of care characteristics, weekly hours spent caring is negatively associated with the likelihood of obtaining a degree qualification and being employed. Caring at age 18/19 may have a stronger impact on obtaining a university degree than caring at other ages. Providing care after age 22 negatively impacted employment outcomes. Having a degree qualification and parental educational attainment buffered the negative impact of providing care on employment. Our results highlight the importance of supporting the needs of young adults providing informal care while making key life course transitions

Inequalities in associations between young adult caregiving and social relationships: Evidence from the UK Household Longitudinal Study

Introduction: Young adult caregivers (aged 16–29 years) are an important but underrecognized group of informal caregivers. There is some evidence suggesting that young adult caregivers have fewer social relationships. However, this research has been largely cross-sectional in design or restricted to caregivers, providing no comparison with noncaregivers. Further, there is little evidence on whether and to what extent there are inequalities in associations between young adult caregiving and social relationships by gender, age, caregiving intensity, or household income./ Methods: Using five waves of data on 3-4000 young adults aged 16–29 from the UK Household Longitudinal Study, we investigated associations between becoming a young adult caregiver and subsequent social relationships (number of close friends and participation in organized social activities) in the short-term (1–2 years after caregiving initiation) and longer-term (4–5 years later). We also assessed differences by gender, age, household income, and caregiving intensity./ Results: Overall, those who became young adult caregivers, and particularly those providing 5+ h/week, reported fewer friends in the short- but not longer-term. No associations were observed between young adult caregiving and participation in organized social activities. Also, there was no evidence of differences by gender, age, income, or caregiving hours./ Conclusions: Becoming a young adult caregiver is associated with a reduction in number of close friends, particularly in the short-term. Given the importance of practical and emotional support provided by friends, the early identification of young adult caregivers and greater population awareness of caring in young adulthood may help to mitigate the effects on social relationships