Life-course pathways to psychological distress: a cohort study

Objectives Early life factors, like intelligence and socioeconomic status (SES), are associated with health outcomes in adulthood. Fitting comprehensive life-course models, we tested (1) the effect of childhood intelligence and SES, education and adulthood SES on psychological distress at midlife, and (2) compared alternative measurement specifications (reflective and formative) of SES. Design Prospective cohort study (the Aberdeen Children of the 1950s). Setting Aberdeen, Scotland. Participants 12 500 live-births (6282 boys) between 1950 and 1956, who were followed up in the years 2001–2003 at age 46–51 with a postal questionnaire achieving a response rate of 64% (7183). Outcome measures Psychological distress at age 46–51 (questionnaire). Results Childhood intelligence and SES and education had indirect effects on psychological distress at midlife, mediated by adult SES. Adult SES was the only variable to have a significant direct effect on psychological distress at midlife; the effect was stronger in men than in women. Alternative measurement specifications of SES (reflective and formative) resulted in greatly different model parameters and fits. Conclusions Even though formative operationalisations of SES are theoretically appropriate, SES is better specified as reflective than as a formative latent variable in the context of life-course modelling

Typical intellectual engagement and cognition in the ninth decade of life: The Lothian Birth Cohort 1921

Investment traits--the tendency to seek out and engage in cognitive activity--might affect intellectual growth across the life span, specifically the development from fluid to crystallized intelligence. Here we explore how childhood IQ at age 11 years, IQ at age 79, and the investment trait Typical Intellectual Engagement (TIE) at age 81 affect the mean level and change in verbal fluency scores, used as an indicator of crystallized intelligence, across the ages 79, 83, and 87 in the Lothian Birth Cohort 1921 (maximum N = 569; Deary, Whiteman, Starr, Whalley, & Fox, 2004). A first latent growth model showed significant variance in the mean level of verbal fluency and significant decline in verbal fluency from age 79 to age 87. The rate of change was invariant across study participants in the Lothian Birth Cohort 1921. A second model found that IQ at age 11 significantly predicted IQ at age 79 (β = .66; p < .001), which in turn predicted verbal fluency and TIE in the ninth decade of life with standardized path parameters of .46 and .15 (p < .001), respectively. TIE had a significant association with verbal fluency (β = .14, p = .002); together, IQ at age 11 and 79 and TIE accounted for 25.5% of the variance in verbal fluency. A final model identified the TIE subfactor of intellectual curiosity as a significant mediator of the effect of IQ on verbal fluency; the TIE subfactors abstract thinking, reading, and problem solving showed no significant associations. In summary, TIE--in particular, intellectual curiosity--significantly mediated the effects of IQ on crystallized intelligence in old age. Because there was no significant between-subjects variance in verbal fluency trajectories in the current study, neither TIE nor IQ were associated with individual differences in cognitive decline

Intellect and Cognitive Performance in the Lothian Birth Cohort 1936

Investment personality traits are thought to positively affect cognitive performance in old age, even after controlling for prior cognitive ability. In the Lothian Birth Cohort 1936 (N = 1,091), a cross-lagged model tested for reciprocal effects of the investment trait Intellect on verbal fluency, an indicator of crystallized intelligence, at age 70 and 73 years, while adjusting for general IQ at age 11 and 70 years. Intellect at age 70 was weakly associated with contemporaneous verbal fluency but had no significant effects on fluency at age 73. Conversely, verbal fluency at age 70 was significantly, positively related to Intellect at age 73. The results suggest that better verbal fluency precedes intellectual investment in old age rather than the other way around

Marital status and reproduction: associations with childhood intelligence and adult social class in the Aberdeen children of the 1950s study

Childhood intelligence (age 11) and occupational social status at midlife (age 46 to 51) was associated with marital status and reproduction in a sample from the Aberdeen Children of the 1950s cohort study (N = 9614). Male and female divorcees had lower childhood intelligence test scores than their married counterparts, but no meaningful difference was found between ever- and never-married individuals. Lower occupational social status increased the odds of being never-married, divorced, separated or widowed compared to being married by 53% to 26% in men (N = 2716) but not in women (N = 2920). Higher intelligence scores were associated with being married rather than divorced at midlife with odds ratios (OR) of 0.86 (Confidence Interval of 95% of 0.76 to 0.99) in men, and 0.87 (0.77 to 0.98) in women. In men, lower intelligence predicted having offspring (0.69; 0.59 to 0.81), while in women, higher occupational status was associated with lower odds of having children (0.66; 0.55 to 0.76). An interaction term showed that high intelligence women remained childless in the top occupational classes but, in the lower social groups, mothers were more intelligent than their childless peers. Intelligence or occupational status were not associated with the number of offspring in both sexes

Childhood intelligence, locus of control and behaviour disturbance as determinants of intergenerational social mobility: British Cohort Study 1970

Determinants of intergenerational social mobility were examined in 8287 men from the British Cohort Study 1970. Confirming previous research, parental social class, childhood intelligence, and educational qualifications were the strongest predictors of occupational social class at the age of 30. Locus of control and childhood behaviour disturbance had independent significant effects and accounted for additional amounts of variance. Self-esteem had only a trivial influence on social mobility. Structural equation modelling using full information maximum likelihood estimation demonstrated that: educational qualifications mediated other predictors' effects, accounting for the greatest amount of variance in people's own social status attainment; there was a substantial overlap of childhood behavioural disturbance, intelligence, and locus of control; there were effects of parental social class on own occupational social class attainment. Intergenerational social mobility is determined by a nexus of inter-correlated variables whose independent effects remain difficult to disentangle

Childhood socioeconomic status and adult health: comparing formative and reflective models in the Aberdeen Children of the 1950s Study (prospective cohort study)

Background Health at midlife is associated with early-life socioeconomic status (SES), intelligence and education; the latter often used as a marker of SES in adulthood. SES is typically modelled as a latent construct with reflective indicators (where the construct causes the variables) but may be better operationalised as a formative trait (where the variables cause the construct). In this report, the authors explain the difference between these two approaches and evaluate reflective and formative modelling for the prediction of health outcomes. Methods The Aberdeen Children of the 1950s Study comprises 12150 children from the Aberdeen area of Scotland, of whom 7183 completed a follow-up questionnaire in middle age. Data were available on indicators of parental SES at birth of the participant, childhood intelligence at age 11 and education and self-rated health at midlife. Results Childhood SES predicted childhood intelligence and educational attainment in adulthood, both of which partially mediated the effects of SES on self-rated health. Both approaches produced well-fitting models (CFI>0.99, TLI>0.99 and RMSEA<0.03), detected indirect effects from parental SES to health (all ps<0.001) and accounted for similar proportions of variance in health. Conclusions In these data, there was little difference between reflective and formative models of SES in their ability to elucidate pathways from childhood SES to adult health. Formative approaches to modelling SES seem appropriate theoretically, yet reflective models were equally informative. The outcome chosen here was self-rated health, but the models are extensible to other health outcomes. Results may differ in other data sets, suggesting that it is first appropriate to compare both strategies

Help will be welcomed from every quarter: the work of William Boyd and the Educational Institute of Scotland's Research Committee in the 1920s

This paper discusses evidence, collected during an ESRC-funded project ('Reconstructing a Scottish School of Educational Research, 1925-1950'), of a remarkable vision to involve teachers in educational research in Scotland by the Educational Institute of Scotland in the 1920s through the work of its Research Committee. Led by William Boyd, the Committee thought that involvement in research was a crucial stepping stone towards achieving professional status for teachers. It conducted a number of detailed investigations involving teachers, thereby introducing research into the consciousness and practice of teachers. This paved the way for Scotland to make significant contributions to educational research on the international stage

Intelligence, social class of origin, childhood behavior disturbance and education as predictors of status attainment in midlife in men: The Aberdeen Children of the 1950s study

In a birth cohort of 6281 men from Aberdeen, Scotland, social class of origin, childhood intelligence, childhood behavior disturbance and education were examined as predictors of status attainment in midlife (46 to 51 years). Social class of origin, intelligence and behavior disturbance were conceptualized as correlated predictors, whose effects were hypothesized to be partially mediated by educational qualifications. A structural equation model using Full Information Maximum Likelihood estimation confirmed that education had the strongest direct effect on status attainment at midlife. Furthermore, education partially mediated the effects of social class of origin and childhood intelligence, and fully mediated the effects of behavior disturbance on status attainment. Social class of origin, childhood intelligence and behavior disturbance were strongly inter-correlated. After controlling for these associations, educational and social status attainments were influenced to a considerably greater extent by childhood intelligence than by social class of origin