Causes and Consequences of Cognitive Functioning Across the Life Course

Variation in Adult Cognition Across Domains and Life Course Place Effects in the UK

This study explores the role that place of birth and place of residence have in variation in cognition in adulthood in the UK. We take advantage of both the large sample size and number of cognitive domains in the UK Biobank to estimate the effect of place of birth and place of residence on adulthood cognition using multilevel modeling. We find, consistent with studies in the US, that place effects at both time points contribute modest variation (<3% of the variation) across all measured cognitive domains, suggesting a relative lack of contribution of shared environments in explaining future Alzheimer's Disease and Related Dementias. Moreover, the geographical contribution to cognitive function in adulthood was slightly larger for females than for males. This study is among the first to explore the impact of both the independent and joint associations of place of birth and place of residence with different cognitive domains.

Socioeconomic and genomic roots of verbal ability from current evidence

This research examines how the human genome and SES jointly and interactively shape verbal ability among youth in the U.S. The youth are aged 12-18 when the study starts. The research draws on findings from the latest GWAS as well as a rich set of longitudinal SES measures at individual, family and neighborhood levels from Add Health (N = 7194). Both SES and genome measures predict verbal ability well separately and jointly. More interestingly, the inclusion of both sets of predictors in the same model corrects for about 20% upward bias in the effect of the education PGS, and implies that about 20-30% of the effects of parental SES are not environmental, but parentally genomic. The three incremental R2s that measure the relative contributions of the two PGSs, the genomic component in parental SES, and the environmental component in parental SES are estimated to be about 1.5%, 1.5%, and 7.8%, respectively. The total environmental R2 and the total genomic R2 are, thus, 7.8% and 3%, respectively. These findings confirm the importance of SES environment and also pose challenges to traditional social-science research. Not only does an individual's genome have an important direct influence on verbal ability, parental genomes also influence verbal ability through parental SES. The decades-long blueprint of including SES in a model and interpreting their effects as those of SES needs to be amended accordingly. A straightforward solution is to routinely collect DNA data for large social-science studies granted that the primary purpose is to understand social and environmental influences.

Early-life socioeconomic status, adolescent cognitive ability, and cognition in late midlife: Evidence from the Wisconsin Longitudinal Study

Although the association between childhood socioeconomic status (SES) and late-life cognition is well-established, the mechanisms underlying this association are less clear. One important potential mediator seldom examined is adolescent cognitive ability. To address this gap, we examined 5,880 respondents from the Wisconsin Longitudinal Study, which follows a random sample of high school students who graduated from Wisconsin high schools in 1957. Structural equation models were used to examine the direct and indirect effects of childhood SES on cognition in late midlife through adolescent cognitive ability, educational attainment, midlife economic condition, and midlife health. Cognitive function was measured as a latent variable composed of scores from 6 cognitive assessments including immediate and delayed recall, digit ordering, letter and category fluency, and a subset of the Wechsler Adult Intelligence Scale similarities test. We found that childhood SES predicts cognition in late midlife, and this association is largely mediated by adolescent cognitive ability and educational attainment and to a lesser extent by midlife economic condition and health. The findings underscore the long-arm of childhood SES in cognitive function in later life and highlight the complex life-course pathways underlying the association between childhood SES and cognition.

Interviewers' Ratings of Respondents' Health: Predictors and Association With Mortality

OBJECTIVES

Recent research indicates that survey interviewers' ratings of respondents' health (IRH) may provide supplementary health information about respondents in surveys of older adults. Although IRH is a potentially promising measure of health to include in surveys, our understanding of the factors contributing to IRH remains incomplete.

METHODS

We use data from the 2011 face-to-face wave of the Wisconsin Longitudinal Study, a longitudinal study of older adults from the Wisconsin high school class of 1957 and their selected siblings. We first examine whether a range of factors predict IRH: respondents' characteristics that interviewers learn about and observe as respondents answer survey questions, interviewers' evaluations of some of what they observe, and interviewers' characteristics. We then examine the role of IRH, respondents' self-rated health (SRH), and associated factors in predicting mortality over a 3-year follow-up.

RESULTS

As in prior studies, we find that IRH is associated with respondents' characteristics. In addition, this study is the first to document how IRH is associated with both interviewers' evaluations of respondents and interviewers' characteristics. Furthermore, we find that the association between IRH and the strong criterion of mortality remains after controlling for respondents' characteristics and interviewers' evaluations of respondents.

DISCUSSION

We propose that researchers incorporate IRH in surveys of older adults as a cost-effective, easily implemented, and supplementary measure of health.

What Skills Can Buy: Transmission of advantage through cognitive and noncognitive skills

Parental income and wealth contribute to children's success but are at least partly endogenous to parents' cognitive and noncognitive skills. We estimate the degree to which mothers' skills measured in early adulthood confound the relationship between their economic resources and their children's postsecondary education outcomes. Analyses of NLSY79 suggest that maternal cognitive and noncognitive skills attenuate half of parental income's association with child baccalaureate college attendance, a fifth of its association with elite college attendance, and a quarter of its association with bachelor's degree completion. Maternal skills likewise attenuate a third of parental wealth's association with children's baccalaureate college attendance, half of its association with elite college attendance, and a fifth of its association with bachelor's degree completion. Observational studies of the relationship between parents' economic resources and children's postsecondary attainments that fail to account for parental skills risk seriously overstating the benefits of parental income and wealth.

Does Growing Childhood Socioeconomic Inequality Mean Future Inequality in Adult Health?

Over the past half century, American children have experienced increasingly unequal childhoods. The goal of this article is to begin to understand the implications of recent trends in social and economic inequalities among children for the future of inequalities in health among adults. The relative importance of many of the causal pathways linking childhood social and economic circumstances to adult health remains underexplored, and we know even less about how these causal pathways have changed over time. I combine a series of original analyses with reviews of relevant literature in a number of fields to inform a discussion of what growing childhood inequalities might mean for future inequalities in adult health. In the end, I argue that there is good reason to suppose that growing inequalities in children's social and economic circumstances will lead to greater heterogeneity in adults' morbidity and mortality.

Cohort profile: Wisconsin longitudinal study (WLS)

The Wisconsin Longitudinal Study (WLS) is a longitudinal study of men and women who graduated from Wisconsin high schools in 1957 and one of their randomly selected siblings. Wisconsin is located in the upper midwest of the United States and had a population of approximately 14 000 000 in 1957, making it the 14th most populous state at that time. Data spanning almost 60 years allow researchers to link family background, adolescent characteristics, educational experiences, employment experiences, income, wealth, family formation and social and religious engagement to midlife and late-life physical health, mental health, psychological well-being, cognition, end of life planning and mortality. The WLS is one of the few longitudinal data sets that include an administrative measure of cognition from childhood. Further, recently collected saliva samples allow researchers to explore the inter-relationships among genes, behaviours and environment, including genetic determinants of behaviours (e.g. educational attainment); the interactions between genes and environment; and how these interactions predict behaviours. Most panel members were born in 1939, and the sample is broadly representative of White, non-Hispanic American men and women who have completed at least a high school education. Siblings cover several adjoining cohorts: they were born primarily between 1930 and 1948. At each interview, about two-thirds of the sample lived in Wisconsin, and about one-third lived elsewhere in the United States or abroad. The data, along with documentation, are publicly accessible and can be accessed at http://www.ssc.wisc.edu/wlsresearch/. Requests for protected data or assistance should be sent to wls@ssc.wisc.edu.