Cognitive Ability In Early Adulthood Research Articles

Foster care leads to sustained cognitive gains following severe early deprivation

This study examined longitudinal data from the Bucharest Early Intervention Project, a randomized controlled trial of foster care as an alternative to institutional care following exposure to severe psychosocial deprivation. We report data from 135 participants assessed in early adulthood (age 18 y). We find that 16 y after randomization occurred, those who had been randomized to high-quality foster care had significantly higher IQ scores (9 points, 0.6 SD) than those randomized to care as usual. Mediation analyses provide evidence that the causal effect of the intervention on cognitive ability in early adulthood could be explained, in part, by higher-quality caregiving and attachment security. These findings indicate that early investment in family care as an alternative to institutional care leads to sustained gains in cognitive ability. Fostering caregiving relationships is a likely mechanism of the intervention. In addition, exploratory analyses indicate that stable placements throughout childhood are associated with the greatest long-term gains in cognitive ability. Whether early interventions for infants and young children lead to lasting change has significant implications for decisions to invest in programs aimed at improving children's developmental outcomes.

Education and Cognitive Functioning Across the Life Span

Cognitive abilities are important predictors of educational and occupational performance, socioeconomic attainment, health, and longevity. Declines in cognitive abilities are linked to impairments in older adults’ everyday functions, but people differ from one another in their rates of cognitive decline over the course of adulthood and old age. Hence, identifying factors that protect against compromised late-life cognition is of great societal interest. The number of years of formal education completed by individuals is positively correlated with their cognitive function throughout adulthood and predicts lower risk of dementia late in life. These observations have led to the propositions that prolonging education might (a) affect cognitive ability and (b) attenuate aging-associated declines in cognition. We evaluate these propositions by reviewing the literature on educational attainment and cognitive aging, including recent analyses of data harmonized across multiple longitudinal cohort studies and related meta-analyses. In line with the first proposition, the evidence indicates that educational attainment has positive effects on cognitive function. We also find evidence that cognitive abilities are associated with selection into longer durations of education and that there are common factors (e.g., parental socioeconomic resources) that affect both educational attainment and cognitive development. There is likely reciprocal interplay among these factors, and among cognitive abilities, during development. Education–cognitive ability associations are apparent across the entire adult life span and across the full range of education levels, including (to some degree) tertiary education. However, contrary to the second proposition, we find that associations between education and aging-associated cognitive declines are negligible and that a threshold model of dementia can account for the association between educational attainment and late-life dementia risk. We conclude that educational attainment exerts its influences on late-life cognitive function primarily by contributing to individual differences in cognitive skills that emerge in early adulthood but persist into older age. We also note that the widespread absence of educational influences on rates of cognitive decline puts constraints on theoretical notions of cognitive aging, such as the concepts of cognitive reserve and brain maintenance. Improving the conditions that shape development during the first decades of life carries great potential for improving cognitive ability in early adulthood and for reducing public-health burdens related to cognitive aging and dementia.

The interplay between cognitive ability, alcohol consumption, and health characteristics.

Higher cognitive ability is associated with favourable health characteristics. The relation between ability and alcohol consumption, and their interplay with other health characteristics, is unclear. We aimed to assess the relationship between cognitive ability and alcohol consumption and to assess whether alcohol consumption relates differently to health characteristics across strata of ability. For 63 120 Norwegian males, data on cognitive ability in early adulthood were linked to midlife data on alcohol consumption frequency (times per month, 0-30) and other health characteristics, including cardiovascular risk factors and mental distress. Relations were assessed using linear regression and reported as unstandardised beta coefficients [95% confidence interval (CI)]. The mean ± s.d. frequency of total alcohol consumption in the sample was 4.0 ± 3.8 times per month. In the low, medium, and high group of ability, the frequencies were 3.0 ± 3.3, 3.7 ± 3.5, and 4.7 ± 4.1, respectively. In the full sample, alcohol consumption was associated with physical activity, heart rate, fat mass, smoking, and mental distress. Most notably, each additional day of consumption was associated with a 0.54% (0.44-0.64) and 0.14% (0.09-0.18) increase in the probability of current smoking and mental distress, respectively. In each strata of ability (low, medium, high), estimates were 0.87% (0.57-1.17), 0.48% (0.31-0.66) and 0.49% (0.36-0.62) for current smoking, and 0.44% (0.28-0.60), 0.10% (0.02-0.18), and 0.09% (0.03-0.15) for mental distress, respectively. Participants with low cognitive ability drink less frequently, but in this group, more frequent alcohol consumption is more strongly associated with adverse health characteristics.

Shift work and cognitive aging: a longitudinal study.

Objectives The few studies of shift work and late life cognitive functioning have yielded mixed findings. The aim of the present study is to estimate the association between shift-work experience and change in cognitive performance before and after retirement age among older adults who were gainfully employed. Methods Five hundred and ninety five participants with no dementia were followed up for a mean of 17.6 standard deviation (SD) 8.8 years from a Swedish population-based sample. Participants had self-reported information on any type of shift-work experience (ever/never) in 1984 and measures of cognitive performance (verbal, spatial, memory, processing speed, and general cognitive ability) from up to 9 waves of cognitive assessments during 1986-2012. Night work history (ever/never) from 1998-2002 was available from a subsample (N=320). Early adult cognitive test scores were available for 77 men. Results In latent growth curve modeling, there were no main effects of "any-type" or night shift work on the mean scores or rate of change in any of the cognitive domains. An interaction effect between any-type shift work and education on cognitive performance at retirement was noted. Lower-educated shift workers performed better on cognitive tests than lower-educated day workers at retirement. Sensitivity analyses, however, indicated that the interactions appeared to be driven by selection effects. Lower-educated day workers demonstrated poorer cognitive ability in early adulthood than lower-educated shift workers, who may have selected jobs entailing higher cognitive demand. Conclusion There was no difference in late-life cognitive aging between individuals with a history of working shifts compared to those who had typical day work schedules during midlife.

Effects of paternal age and offspring cognitive ability in early adulthood on the risk of schizophrenia and related disorders

Advanced paternal age (APA) and intelligence quotient (IQ) are both associated with the risk of schizophrenia spectrum disorder (SSD) in young adult offspring. We hypothesized that the offspring SSD risk gradient associated with paternal age is mediated by offspring IQ. We investigated joint and separate associations of paternal age and offspring IQ with the risk of SSD. We used IQ routinely measured at conscription in Danish males (n=138,966) from cohorts born in 1955–84 and in 1976–1993 and followed them from a year after the conscription through 2010. We used Cox regression to estimate the incidence rate ratio (IRR) of SSD. During the follow-up, 528 men developed SSD (incidence rate [IR] 5.2 and 8.6 per 10,000 person-years in the first and second cohorts, respectively). APA was associated with higher risk of SSD (IRR, 1.32; 95% CI, 1.10–1.60 per a ten-year increase in paternal age). A higher IQ was associated with lower SSD risk (IRR, 0.68; 95% confidence interval [CI], 0.63–0.74 per one SD increase). The IR of SSD was higher among persons who were draft-exempt for health reasons (<20% of the men). Overall, there was little evidence of lower premorbid IQ in APA-related SSD (individuals who developed SSD and were also offspring of older fathers). Our results do not support the notion that risk gradient for offspring SSD associated with paternal age is mediated by offspring IQ.

The relationship between cognitive ability and depression: a longitudinal data analysis.

There is literature indicating cognitive ability and depression are related, but few studies have examined the direction of the relationship. This study examined the relationship between depression levels and cognitive abilities from adolescence to early adulthood. Using the National Longitudinal Study of Adolescent Health (n=14,322), this study used path modeling to investigate the relationship between depression and cognitive ability at baseline and again 8years later. After controlling for initial levels of depression, cognitive ability, and other covariates, depressive symptoms in adolescence are related to cognitive ability in early adulthood, but adolescent cognitive ability is not related to adult depression levels. Moreover, after controlling for adolescent levels of depression and cognitive ability, the cognitive ability-depression relationship disappears in adulthood. The cognitive ability-depression relationship appears early in life, and it is likely that the presence of depressive symptoms leads to lower cognitive ability. Thus, intervening at early signs of depression not only can help alleviate depression, but will likely have an effect of cognitive ability as well.

Cognitive ability in early adulthood is associated with later suicide and suicide attempt: the role of risk factors over the life course

Cognitive ability/intelligence quotient (IQ) in youth has previously been associated with subsequent completed and attempted suicide, but little is known about the mechanisms underlying the associations. This study aims to assess the roles of various risk factors over the life course in explaining the observed relationships. The present investigation is a cohort study based on data on IQ test performance and covariates, recorded on 49 321 Swedish men conscripted in 1969-1970, at ages 18-20 years. Information on suicides and hospital admissions for suicide attempt up to the age of 57 years, childhood and adult socio-economic position, and adult family formation, was obtained from linkage to national registers. Lower IQ was associated with increased risks of both suicide and suicide attempt during the 36 years of follow-up. The associations followed a dose-response pattern. They were attenuated by approximately 45% in models controlling for social background, mental ill-health, aspects of personality and behavior, adult socio-economic position and family formation. Based on one-unit decreases in IQ test performance on a nine-point scale, the hazard ratios between ages 35 and 57 years were: for suicide 1.19 [95% confidence interval (CI) 1.13-1.25], fully adjusted 1.10 (95% CI 1.04-1.18); and for suicide attempt 1.25 (95% CI 1.20-1.31), fully adjusted 1.14 (95% CI 1.09-1.20). Cognitive ability was found to be associated with subsequent completed and attempted suicide. The associations were attenuated by 45% after controlling for risk factors measured over the life course. Psychiatric diagnosis, maladjustment and aspects of personality in young adulthood, and social circumstances in later adulthood, contributed in attenuating the associations.

Cognitive ability in early adulthood as a predictor of habitual drug use during later military service and civilian life: The Vietnam Experience Study

BackgroundRecent reports have linked cognitive ability (IQ) with alcohol dependency, but the relationship with illegal drug use is not well understood. MethodsParticipants were 14,362 male US Vietnam veterans with IQ test results at entry into military service in 1965–1971 (mean age 22.58) who participated in a telephone interview in 1985–1986. A structured diagnostic telephone interview was used to ascertain habitual drug use during military service (for once a week, ≥3 months) and in civilian life (in the past 12 months, ≥once a week), combat exposure, and post-traumatic stress disorder according to established Diagnostic and Statistical Manual of Mental disorders criteria (version III). ResultsIn unadjusted analysis, men with high IQ scores were less likely to be habitual users of cannabis (OR=0.89, 95% CI=0.86, 0.93), cocaine (OR=0.69, 95% CI=0.61, 0.78), heroin (OR=0.80, 95% CI=0.73, 0.88), amphetamines (OR=0.90, 95% CI=0.83, 0.98), barbiturates (OR=0.79, 95% CI=0.72, 0.86) and LSD (OR=0.91, 95% CI=0.82, 0.99) during military service and civilian life. These associations were markedly attenuated after adjustment for socioeconomic status in early and later civilian life. ConclusionIn this cohort, socioeconomic position might lie on the pathway linking earlier IQ and later habitual drug use but might also act as a surrogate for IQ. This suggests interventions to prevent drug use could attempt to improve early life IQ and opportunities for employment.

Low cognitive ability in early adulthood is associated with reduced lung function in middle age: the Vietnam Experience Study

ObjectiveReduced lung function has been linked to poorer cognitive ability later in life. In the present study, the authors examined the converse: whether there was a prospective association between cognitive...

Cognitive ability in early adulthood is associated with systemic inflammation in middle age: The Vietnam experience study

We examined the prospective association between cognitive ability in early adulthood and erythrocyte sedimentation rate, a marker of inflammation, in middle age. Participants were 4256 male Vietnam era US veterans. Data on cognitive ability, assessed by the Army General Technical Test, ethnicity, and place of service were extracted from enlistment files. Smoking behaviour, alcohol consumption, basic socio-demographics, and whether participants suffered from a physician diagnosed chronic disease were determined by telephone interview in middle-age in 1985. Erythrocyte sedimentation rate, cholesterol, blood pressure, height, and weight were measured at a 3-day medical examination in 1986. In linear regression models that adjusted for age and then additionally for circumstantial, socio-demographic, lifestyle, and health factors, poor cognitive ability in early adulthood was associated with greater erythrocyte sedimentation rate in middle age, β = −.09. Thus, it would appear that not only does systemic inflammation influence cognition, but also that poor cognitive ability earlier in life is associated with inflammation in middle-age.

Does Parental Education have a Moderating Effect on the Genetic and Environmental Influences of General Cognitive Ability in Early Adulthood?

Hereditary influences account for a substantial proportion of the variance in many cognitive abilities. However, there is increasing recognition that the relative importance of genetic and environmental influences may vary across different socioeconomic levels. The overall goal of the present study was to examine whether parental education has a moderating effect on genetic and environmental influences of general cognitive ability in early adulthood (age 19.6 +/- 1.5). Participants were 5,955 male twins from the Vietnam Era Twin (VET) Registry. Significant effects of parental education on mean level of general cognitive ability scores were found, but a model without moderating effects of parental education on genetic or environmental influences on cognitive scores proved to be the best fitting model. Some, but not all, previous studies have found significant moderating effects; however, no consistent pattern emerged that could account for between-study differences regarding moderating effects on genetic and environmental influences.

Cognitive ability in early adulthood and risk of 5 specific psychiatric disorders in middle age: the Vietnam experience study.

Lower cognitive ability is a risk factor for some forms of psychopathology, but much of the evidence for risk is based on individuals who required specialist care. It is unclear whether lower ability influences the risk of particular patterns of comorbidity. To examine the relation between premorbid cognitive ability in early adulthood and the risk of major depression, generalized anxiety disorder (GAD), posttraumatic stress disorder (PTSD), alcohol and other drug abuse or dependence, and comorbid forms of these conditions in midlife. Prospective cohort study in which cognitive ability was measured on enlistment into military service at a mean age of 20.4 years and psychiatric disorder was assessed by structured diagnostic interview at a mean age of 38.3 years. The United States. A total of 3258 male veterans, participants in the Vietnam Experience Study. Major depression, GAD, PTSD, and alcohol or other drug abuse or dependence since enlistment and currently, diagnosed according to the DSM-III. Lower cognitive ability was associated with an increased risk of depression, GAD, alcohol abuse or dependence, and PTSD and with some patterns of comorbidity. For a 1-SD decrease in cognitive ability, unadjusted odds ratios (95% confidence interval) for having these disorders currently were 1.32 (1.12-1.56) for depression, 1.43 (1.27-1.64) for GAD, 1.20 (1.08-1.35) for alcohol abuse or dependence, 1.39 (1.18-1.67) for PTSD, 2.50 (1.41-4.55) for PTSD plus GAD, 2.17 (1.47-3.22) for PTSD plus GAD plus depression, and 2.77 (1.12-6.66) for all 4 disorders. Most associations remained statistically significant after adjustment for confounders. Lower cognitive ability is a risk factor for several specific psychiatric disorders, including some forms of comorbidity. Understanding the mechanisms whereby ability is linked to individual patterns of psychopathology may inform intervention.

Apolipoprotein E is not Related to Memory Abilities at 70 Years of Age

APOE e4-related memory deficits were reported in a normal population aged between 50 and 60 when controlling for general cognitive ability in early adulthood. This extended findings of APOE e4 effects on cognitive ability in 60-80-year-olds to a younger group and confirmed that this effect relates to changes in memory ability with age. The present study tests the association of APOE e4 variation with verbal and spatial memory in a sample of 70-year-olds both adjusted and non-adjusted for childhood and adult general cognitive ability. The 1,013 participants comprise surviving members of the 1947 Scottish Mental Survey resident in the Lothian area of Scotland. They were tested on general cognitive ability at age 11 years and followed up at about age 70 with tests of verbal (immediate and delayed) and spatial memory. General linear models were used to test the association between variation in the APOE polymorphism (e4 presence vs. absence) and memory measures. Of the eight measures tested, Spatial span forward was significantly associated with APOE e4 variation (P = 0.04) when adjusting for IQ, whereas Logical memory immediate was associated with APOE e4 variation (P = 0.04) in the analysis not controlling for IQ. Neither of these tests was significant when a correction for multiple testing was applied. APOE e4 does not influence memory abilities in a normal population of 70-year-olds.