Life Course Perspective Research Articles

Modifiable risk factors for cognitive decline in community-dwelling older adults differ by sex and APOE4.

The extent to which lifestyle shapes trajectories of normal cognitive aging, and the factors with highest potential for mitigating cognitive decline, remain poorly uncharacterized. Participants of the Rancho Bernardo Study underwent demographic, health, and behavioral characterization at baseline, along with up to seven cognitive assessments over a 27-year follow-up period. Factor analysis of 24 baseline risk variables identified 9 composite factors. Mixed effects models on data from 1489 participants (aged 45-95 years at baseline) assessed prediction of cognitive change by baseline factor scores. Models were repeated stratified by sex and APOE4 status. Factors of hyperlipidemia and obesity; marriage and depression; occupation and education; and physical activity and subjective health best predicted rates of decline across multiple cognitive domains. Distinct risk profiles were identified for women and men, and for APOE4 carriers and non-carriers. Models of composite risk estimated that potential savings could amount to 7-9.5 years of preserved cognitive healthspan for low- versus high-risk profiles. Magnitudes of aggregate risk effects were greater among women across cognitive domains, and for APOE4 carriers for memory and verbal fluency. Multifactorial life-course approaches to manage cardiometabolic health and promote physical, cognitive, and social engagement, may help to mitigate cognitive decline with age, with composite risk associated with up to a decade of preserved cognitive health-span. Differences by sex and APOE4 in risk profiles and their potential for risk reduction, highlight the importance of developing personalized recommendations for multi-domain approaches to cognitive health maintenance throughout the life-course.

Childhood Housing Condition and Old Age Health Among Chinese: The Mediation Role of Adulthood Socioeconomic and Medical History.

Guided by the lifecourse perspective and social determinants of health framework, this study examined the association of childhood housing with old age health among Chinese and its midlife mediators. Respondents were middle-aged and older adults (aged 45+) from the China Health and Retirement Longitudinal Study (N = 12,842). They were asked about their childhood housing conditions (e.g., if their houses had clean water, water toilet, and electricity). Adulthood socioeconomic and medical history and middle- and old-age health were measured. Causal mediation analysis showed childhood better housing was directly associated with fewer depressive symptoms and better cognition in middle- and older-age, and indirectly through increasing education level. However, the proportion-mediated estimate had very wide confidence intervals. Our findings suggested the importance of broad infrastructure development and adult continuing education programs among those who grew up in poor housing conditions to promote mental health in older age.

A Life-Course Approach to Gestational Exposure to Famine and Risk of Mortality.

A Life-Course Approach to Gestational Exposure to Famine and Risk of Mortality.

Life in green: Associations between greenspace availability and mental health over the lifecourse - A 40-year prospective birth cohort study.

The beneficial impacts of greenspace availability on mental health are well-documented. However, longitudinal evidence using a spatial lifecourse perspective is rare, leaving the dynamics of how greenspace influences mental health across the lifecourse unclear. This study first uses prospective birth cohort data to examine the associations between greenspace availability in childhood (0-16years) and mental health in adolescence (16years) and between greenspace availability and mental health across adulthood (18-40years). Data were obtained from the Christchurch Health and Development Study, comprised 1,265 cohort members born in Christchurch, New Zealand, in 1977. Mental health outcomes including depressive symptoms, anxiety disorders and suicidal ideation were assessed in adolescence (16years), and in adulthood (18-40years). Greenspace availability from birth to age 40years was measured as the proportion of vegetated areas within circular buffers (radius from 100m to 3000m) around members' geocoded residential addresses using a time-series impervious surfaces data from 1985 to 2015. Bayesian Relevant Lifecourse exposure models examined the associations between childhood greenspace availability and adolescent mental health and tested for critical/sensitive age periods. Generalised Estimating Equation logistic regression models assessed the associations between greenspace availability and mental health across adulthood. These analyses were adjusted for various important individual, family, and area-level covariates. No associations were found between childhood greenspace availability and any adolescent mental health conditions. However, in adulthood, a one standard deviation increase in greenspace availability within 1500m and 2000m buffers was associated with a 12% and 13% reduced risk of depressive symptoms, respectively, after adjusting for various covariates. This study supports the protective effects of greenspace on adult depressive symptoms, highlighting the significance of employing a spatial lifecourse epidemiology framework to examine the long-term effects of environmental factors on health over the lifecourse.

Addressing Neurological Inequities in Developing Countries: Challenges and Strategic Solutions

Abstract Neurological disorders pose one of the most urgent healthcare challenges globally, with a particularly severe impact on low-resource settings. Effective responses to this crisis require timely, intersectoral strategies, and coordinated actions to drive substantial positive changes. Political determinants of health play a crucial role in advancing initiatives in surveillance, prevention, acute care, and rehabilitation for neurological conditions. An essential life-course approach to brain health focuses on early intervention and sustained care throughout an individual’s lifespan. Building a comprehensive system of care, underpinned by robust policies and financial investments, is critical for progress in low-resource countries. In addition, urgent reforms in education are needed to cultivate a skilled neurological workforce that is equipped to meet the demands of these regions. Intersectoral strategies, including telemedicine, mobile health, organized systems of care, helicopter ambulance services, and widespread public awareness campaigns, are vital components for creating an equitable and responsive neurological healthcare framework.

DO STEPCHILDREN PROVIDE DEMENTIA CARE TO AGING BIOLOGICAL PARENTS COMMENSURATE WITH THEIR LEVEL OF NEED?

Abstract The research in this presentation addresses the critical issue of whether divorce, remarriage/repartnering, and stepfamily formation have weakened adult intergenerational bonds due to stepchildren’s weaker commitment to the care of their vulnerable stepparents. A life-course approach is taken to link early relationship characteristics to later care trajectories. We use data from the Longitudinal Study of Generations to examine whether earlier kinship strength with stepmothers and stepfathers increases the amount of care stepchildren provide to meet the needs of their aging stepparents between1997-2022. We use latent growth curve analysis to examine whether the rate of increase in care to stepparents with advancing dementia and functional impairment is stronger when stepchildren in earlier adulthood evaluated their relationship with stepparents as more “kin-like” and “family-like.” In comparison, we also examine rate of change in care for biological mothers and fathers by their levels of functional impairment. We also consider structural characteristics of step-relationships, including the child’s age when the relationship was formed and the number of years the child lived with the stepparent. We expect that earlier reported kinship strength with stepparents will moderate the care response to stepparents’ impairment such that it will approach the care response to biological parents. We expect the severely impaired stepmothers to elicit more care from stepchildren when compared to severely impaired stepfathers. Analyses reveal the conditions under which stepchildren serve as a vital resource to their vulnerable older stepmothers and stepfathers with dementia in complex aging families, which have become increasingly prevalent but remain under-investigated.

GENDERED RACIAL DISPARITIES IN FUNCTIONAL LIMITATIONS: EXPLORING THE ROLE OF LIFE-COURSE FAMILY CARE

Abstract Objectives This study addresses the dearth of research on culturally embodied factors influencing health disparities, focusing on cultural aspects such as family formation timing, living arrangements, familism, and family care responsibilities. By employing “intersectionality” and a life-course approach to “family care,” we aim to understand why minority women are vulnerable to functional limitations. Methods Data come from the MIDUS II, Refresher, and Milwaukee surveys, with a sample of Non-Hispanic Whites and Blacks (N=8,848; 18% Blacks; 53% Women). Measures of family care included age at first childbirth, number of biological children, single or nonmarital parenthood, child loss, co-residence with a disabled child, family caregiving history, and major grandparenting responsibilities. We identified racial disparities in family care profiles and assessed their contribution to health disparities. Results Adverse family care profiles were more common among women, particularly Blacks. Compared to White women, Black women were more likely to experience early and non-marital motherhood, current family care, and major grandparenting roles. Adverse family care profiles were linked to more functional limitations, with differing effects between Black and White women. While early childbearing was more detrimental to White women, caring for disabled family members had a greater adverse effect on Black women. Adverse family care profiles explained one-third of Black-White disparities in functional limitations. Discussion Our findings highlight the social costs of family care, disproportionately affecting minority women. They offer insights into public health policies and interventions aimed at easing the burdens of family care to improve their quality and length of life.

Pacific Islands Families Study: Serum Uric Acid in Pacific Youth and the Associations with Free-Sugar Intake and Appendicular Skeletal Muscle Mass.

Fructose (50% of sucrose/sugar) is one component of free-sugars and is metabolized to uric acid, which is a known risk factor for gout and metabolic syndrome. Pacific peoples in New Zealand experience a higher prevalence of gout, type 2 diabetes, and overweight/obesity than other ethnic groups. Interestingly, despite having a similar body mass index (BMI), they tend to have a higher proportion of appendicular skeletal muscle mass (ASMM) and less fat than other ethnic groups. Given this context, this study aimed to evaluate the associations between serum uric acid (SUA), free-sugar intake, and ASMM. In a nested sub-study from the Pacific Islands Families birth-cohort study, 101 boys and 99 girls (all aged 14 and 15 years) self-reported how often they had consumed foods containing sugar in the past month. Anthropometry, body fatness, and ASMM by dual-energy X-ray absorptiometry and metabolic risk factors, including SUA were measured. Overall, 43% of girls and 57% of boys consumed 'sugary drinks' twice or more a day. When analyzed by group, ASMM was positively related to SUA for both boys and girls (r = 0.593, p < 0.0001). The effect of the intake of 'sugary drinks' on SUA (r = 0.176, p = 0.013) was reduced when ASMM was considered in the relationships. This study shows high SUA levels in Pacific adolescents, with a positive association between ASMM and SUA in both genders. Sugary drink intake was positively associated with SUA in both boys and girls. High ASMM in Pacific people and an increased risk for raised SUA make it important to work with Pacific communities to reduce added sugar intake and adopt integrated, family-based, culturally centered, and life-course approaches to prevent chronic diseases, including gout.

Life-course perspective on the causal mechanism of social functioning in schizophrenia spectrum disorder.

Due to prior emphasis on clinical recovery in Schizophrenia Spectrum Disorder (SSD), improving social functioning (SF) was oftentimes neglected, with ⩽15% of patients achieving social recovery. Priorly, we and others have shown that life-course factors, including childhood adversities, play a role in the occurrence and severity of postmorbid SF impairments, highlighting the need to understand these factors for effective interventions. This study investigates the mechanisms influencing SF in SSD and examines the causal roles of childhood trauma, premorbid adjustment, perceived stigma, self-esteem, and quality of life. This longitudinal study utilized data of 1,057 SSD patients, with measures at baseline, 3 and 6-year follow-up, from the Genetic Risk and Outcome of Psychosis cohort, to unravel the causal mechanism underlying SF utilizing Structural Equation Modeling. Determinants were assessed using validated retrospective and self-report questionnaires. Model development and testing involved a multistage process, encompassing relationships exploration, fit evaluation and model comparison. We developed a probable causal model. Impaired premorbid adjustment emerged as a crucial factor, exerting negative influence on long-term SF, with a direct effect of β = -.252, p < .001 on SF at 3-year follow-up and β = -.056, p = .073 at 6-year follow-up. Childhood trauma exhibited a negative direct effect on SF at 3-year follow-up (β = -.087, p = .039), while demonstrating a substantial carry-over, indirect effect. Elevated perceived stigma negatively affected SF at 3-year follow-up (β = -.112, p = .008). The model explained 9.9% of SF variation at the 3-year follow-up and 54.3% at the 6-year follow-up. While validation is necessary, we found a foundational basis for causal interpretation. Premorbid adjustment, childhood trauma, and perceived stigma are essential life-course factors shaping postmorbid SF in SSD. We recommend interventions covering both prevention and treatment for individuals with established symptoms-addressing childhood trauma, premorbid adjustment, and perceived stigma-to enhance long-term social outcomes and offer actionable insights for clinicians.

Barriers to advancing the sexual and reproductive health agenda in Latin America: a qualitative study of key informants’ perspectives

BackgroundThe effective attainment of sexual, reproductive, and maternal health and rights (SRMHR) requires a holistic life-course approach. This approach should address disparities in healthcare access and rights, guarantee the delivery of high-quality care devoid of discrimination, and underscore rigorous accountability mechanisms throughout the implementation process. Latin American and Caribbean (LAC) countries face significant disparities in SRMHR within and between nations. Vulnerable populations, such as indigenous communities, Afro-descendants, LGBTQI + population, persons with disabilities, older adults, and migrants, often endure discrimination and stigmatization, severely impacting their access to healthcare and health rights. This paper presents the findings from the qualitative component of a broader mixed-methods scoping study aimed at establishing a priority research agenda to address healthcare gaps affecting the SRMHR of vulnerable populations. The qualitative component focused on identifying key challenges hindering progress in SRMHR and access to health services for these populations in the LAC region, drawing on the perspectives of key informants at both regional and national levels.MethodsQualitative research approach employing semi-structured interviews with key informants. A purposive sample comprised of stakeholders from relevant regional organizations and local stakeholders in selected countries (Argentina, Colombia, Peru, Mexico, Guatemala, Jamaica, and Guyana), encompassing government representatives, civil organizations, and academia. A rapid content thematic analysis was conducted to analyze the data obtained from the interviews.ResultsWe interviewed 27 key informants in SRMHR, six at a regional level and 21 at a country level. The region faces barriers around establishing and sustaining agency agendas, such as a lack of political will, political instability, and opposition from civil society groups regarding SRMHR agendas. Policy implementation presents difficulties due to insufficient and unstable funding, weaknesses in sexual and reproductive health programs, unequal policy implementation in federal countries, and the absence of evidence-based policies. The lack of high-quality data and quality indicators poses obstacles, leading to limitations in evidence generation. Access to SRMHR services faces barriers such as the low-quality provision of services, discrepancies between legislation and effective access, insufficient healthcare resources, and resistance from certain healthcare providers.ConclusionAddressing these multifaceted challenges will be crucial in advancing the agenda of sexual, reproductive, and maternal health rights and ensuring effective access to health services for the most vulnerable populations in the LAC region.

Wicked Questions and Perfect Storms Comment on "From Local Action to Global Policy: A Comparative Policy Content Analysis of National Policies to Address Musculoskeletal Health to Inform Global Policy Development"

Schneider and colleagues’1 paper "From Local Action to Global Policy: A Comparative Policy Content Analysis of National Policies to Address Musculoskeletal Health to Inform Global Policy Development" examines musculoskeletal (MSK) policies across 30 of the world’s most populous nations using an adapted World Health Organization (WHO) Health Systems Building Blocks (HSBB) framework. This commentary critiques the findings through a complexity theory lens, emphasizing the amplified wickedness of MSK health challenges, shaped by systemic, socioeconomic, situational, and medical factors. These interconnected elements create varying levels of complexity, making policy implementation increasingly difficult. The commentary calls for addressing funding gaps, promoting integrated care models, and adopting a life-course approach to align MSK policy with global priorities like healthy aging. It advocates for shifting from policy learning to culturally sensitive, actionable implementation, ensuring that MSK healthcare can be effectively delivered in diverse, complex health ecosystems. This approach is critical for fostering equitable and sustainable MSK health solutions globally.

“What Made Me Change”: Transformative Experiences in the Jihadist Radicalization Process

ABSTRACT Disentangling the roots of radicalization leading to violence is a worldwide challenge. Unfortunately, empirical data are scarce. Through fieldwork conducting interviews with Muslim persons deprived of liberty (PDL) in Spanish prisons, this research examines transformative experiences that may have influenced radicalization leading to violence from the 3N model and the life-course perspective lenses. PDL because of jihadist terrorism (n = 30), common criminals who carry out proselytizing work (n = 22), and non-radicals (control group, n = 64) were asked about the turning point in their lives. Their responses were coded into exclusive thematic categories following an inductive-deductive mixed approach. Jihadists and proselytizers identified experiences linking their personal identity to religion—ideological ties—as a transformative point that provided them purpose and sparked the desire for leaving their criminal lifestyle behind. Also, proselytizers referred to family-related experiences—familial ties—as a turning point which also prompted them to criminal desistance, whereas this was not mentioned by jihadists. All groups had in common the experience of incarceration as a major turning point and a moderate level of self-reported religiosity. Overall, these findings contribute to the understanding and prevention of jihadist radicalization.

The perception of major life events across the life course.

To better understand the effects of life events, research interest recently turned to the question of how life events are perceived (e.g., as positive, predictable, or controllable). However, research on this topic primarily focused on young adulthood, leaving it unclear whether and how the perception of life events varies across the life course. In this study, we examined the relationship between age and different perceived event characteristics using nationally representative data from the German Socioeconomic Panel Innovation Sample (N = 1,044). We found that people reported different event types across among age groups. Furthermore, the perception of life events varied across age and depending on whether an event was experienced at a normative age or not. These findings underline the necessity to take on a life-course perspective when examining life events and support theoretical claims on the relevance of age norms in life-event research.

Life Transition and Migration: A Scoping Review

In scientific literature, migration and life-course transition events were shown to be related. The context of migration was selected as a crucial area of study since it was seen that migration occurred as people changed from one role to another, or entered a life stage throughout their lives. The life-course transition was examined in this scoping review as a factor influencing migration. Transition events across life-courses are analyzed from developmental psychology and life-course perspectives. The context of the review is limited to the contemporary industrialized and globalized societies in which migration has become prevalent. This review examined the alignment of life-course transition stages with migration, delving into its possible explanations. 19 research articles were chosen for review based on PRISMA guidelines and the final protocol was registered at Open Science Framework’s open-access registry. Content analysis was employed in the scoping review. It was found that most migrations are aligned with developmental life-course transition events, like movement from school to higher education, college to work, and work to retirement. Analysis of data indicates that older adults are at higher risk of both physical and mental health concerns. An increase in migration within the phase of emerging adulthood due to the flexibility available within the stage of life has been brought out. The phenomenon of migration has been discussed as requiring interventions for the mental health and well-being of minority migrants.

Depression Among Older Adults in China: Effects of Urbanicity Across the Life Course

The global prevalence of depression among older adults continues to increase alongside rapid urban development. Scant attention has been paid, however, to how exposure to urbanicity over the life course affects older adults’ depressive symptoms, particularly in China, which has undergone substantial recent urbanization. Using data from the China Health and Retirement Longitudinal Study (CHARLS) with its Life History Survey, this study adopts a life-course approach to examine the accumulative and sequenced effects of exposure to urbanicity from 1992 to 2018 on depressive symptoms among older adults, alongside the mediating roles of social relationships. Multilevel regression analysis, clustered at the city level, reveals that higher cumulative exposure to urbanicity is associated with reduced depressive symptoms, particularly with constant or increased exposure to higher levels of urbanicity during middle and older adulthood. This protective effect remains robust against the potential influence of health-selective migration but varies by sex and socioeconomic status. Relationships with friends and neighbors mediate the urbanicity–depression association, whereas cumulative urbanicity exposure is negatively associated with satisfaction with the parent–child relationship and aggregates depressive symptoms. These findings underscore the importance of employing the life-course approach to understand the interplay between health and place across the life span.

Reimagining maternal resilience: Incorporating the socioecological framework, lifecourse theory, and weathering hypothesis.

Women of color are at least twice as likely as non-Hispanic White women to die during the perinatal period or deliver infants who are low birthweight, preterm, or die within the first year of life. Maternal stress before and during pregnancy is associated with adverse obstetric outcomes. A growing body of literature has explored maternal resilience as protective factors contributing to healthy maternal and child health (MCH) outcomes. However, several gaps exist in how this construct has been conceptualized and operationalized. First, extant research has primarily conceptualized maternal resilience as individual attributes that enable women to "bounce back" after facing adversity during pregnancy, thereby failing to incorporate the broader systemic and environmental factors that contribute to chronic stress, particularly among vulnerable groups. Second, the literature has largely neglected to examine resilience in relation to maternal stress, therefore not acknowledging that women who experience greater stress will likely require more resources. Third, though resilience has been investigated at discrete life stages, longitudinal research has not been conducted to explore how it develops over the lifecourse. This article critically evaluates the resilience literature, expands upon the gaps described, and proposes a conceptual framework that reimagines material resilience using three population health theories, including Bronfenbrenner's socioecological framework, Elder's lifecourse theory, and Geronimus' weathering hypothesis. The proposed framework will inform future research that examines the development of multilevel resilience resources over the lifecourse as well as interventions to increase resilience and ultimately yield healthier MCH outcomes among vulnerable communities. (PsycInfo Database Record (c) 2024 APA, all rights reserved).

Gestational Diabetes Mellitus and Subsequent Risks of Diabetes and Cardiovascular Diseases: the Life Course Perspective and Implications of Racial Disparities.

Gestational diabetes mellitus (GDM) is one of the most common pregnancy complications worldwide and the prevalence is continuously rising globally. Importantly, GDM is not an isolated complication of pregnancy. Growing evidence suggests that individuals with GDM, compared to those without GDM, have an increased risk of subsequent type 2 diabetes (T2D) and cardiovascular diseases (CVD). Substantial racial and ethnic disparities exist in the risk of GDM. However, the role of race and ethnicity in the progression from GDM to T2D and CVD remains unclear. The purpose of the current review is to summarize recent research about GDM and its life-course impacts on cardiometabolic health, including 1) the peak time of developing T2D and CVD risks after GDM, 2) the racial and ethnic disparities in the risk cardiometabolic diseases after GDM, 3) the biological plausibility and underlying mechanisms, and 4) recommendations for screening and prevention of cardiometabolic diseases among individuals with GDM, collectively to provide an updated review to guide future research. Growing evidence has indicated that individuals with GDM had greater risks of T2D (7.4 to 9.6 times), hypertension (78% higher), and CDV events (74% higher) after GDM than their non-GDM counterparts. More recently, a few studies also suggested that GDM could slightly increase the risk of mortality. Available evidence suggests that key CVD risk factors such as blood pressure, plasma glucose, and lipids levels are all elevated as early as < 1year postpartum in individuals with GDM. The risk of T2D and hypertension is likely to reach a peak between 3-6years after the index pregnancy with GDM compared to normal glycemia pregnancy. Cumulative evidence also suggests that the risk of cardiometabolic diseases including T2D, hypertension, and CVD events after GDM varies by race and ethnicity. However, whether the risk is higher in certain racial and ethnic groups and whether the pattern may vary by the postpartum cardiometabolic outcome of interest remain unclear. The underlying mechanisms linking GDM and subsequent T2D and CVD are complex, often involving multiple pathways and their interactions, with the specific mechanisms varying by individuals of different racial and ethnic backgrounds. Diabetes and CVD risk screening among individuals with GDM should be initiated early during postpartum and continue, if possible, frequently. Unfortunately, adherence to postpartum glucose testing with either obstetrician or primary care providers remained poor among individuals with GDM. A life-course perspective may provide critical information to address clinical and public health gaps in postpartum screening and interventions for preventing T2D and CVD risks in individuals with GDM. Future research investigating the racial- and ethnic-specific risk of progression from GDM to cardiometabolic diseases and the role of multi-domain factors including lifestyle, biological, and socio-contextual factors are warranted to inform tailored and culture-appropriate interventions for high-risk subpopulations. Further, examining the barriers to postpartum glucose testing among individuals with GDM is crucial for the effective prevention of cardiometabolic diseases and for enhancing life-long health.

Nepal Family Cohort study: a study protocol

IntroductionThe Nepal Family Cohort study uses a life course epidemiological approach to collect comprehensive data on children’s and their parents’ environmental, behavioural and metabolic risk factors. These factors can affect...

Genetic variants for Alzheimer's disease and comorbid conditions.

Alzheimer's disease and related dementias (ADRD) frequently co-occur with comorbidities such as diabetes and cardiovascular diseases in elderly populations. Utilize a life-course approach to identify genetic variants that are associated with the co-occurrence of ADRD and another comorbid condition. Research data from African American participants of the Indianapolis-Ibadan Dementia Project (IIDP) linked with electronic medical record (EMR) data and genome-wide association study (GWAS) data were utilized. The age of onset for ADRD was obtained from longitudinal follow-up of the IIDP study. Age of onset for comorbid conditions was obtained from EMR. The analysis included 1177 African Americans, among whom 174 were diagnosed with ADRD. A semi-parametric marginal bivariate survival model was used to examine the influence of single nucleotide polymorphisms (SNPs) on dual time-to-event outcomes while adjusting for sex, years of education, and the first principal component of GWAS data. Targeted analysis of 20 SNPs that were reported to be associated with ADRD revealed that six were significantly associated with dual-disease outcomes, specifically congestive heart failure and cancer. In addition, eight novel SNPs were identified for associations with both ADRD and a comorbid condition. Using a bivariate survival model approach, we identified genetic variants associated not only with ADRD, but also with comorbid conditions. Our utilization of dual-disease models represents a novel analytic strategy for uncovering shared genetic variants for multiple disease phenotypes.

Examining Parent Criminal History as a Predictor of Recidivism From a Life-course Perspective: Testing for Age-differing Salience in Effects

Examining Parent Criminal History as a Predictor of Recidivism From a Life-course Perspective: Testing for Age-differing Salience in Effects