Highlights

► COMT gene can influence cognitive function in developmental stage specific manner. ► A large UK population-based sample with cognition measured at ages 8 and 15 years was used. ► Five functional COMT SNPs were tested for association with cognition. ► COMT rs737865 showed association with reading comprehension, verbal ability and global cognition at age 15 years in pubescent boys only. ► Further studies are necessary in order to make stronger conclusions.

Genetic variation in the catechol-O-methyltransferase gene (COMT) can influence cognitive function, and this effect may depend on developmental stage. Using a large representative British birth cohort, we investigated the effect of COMT on cognitive function (verbal and non-verbal) at ages 8 and 15 years taking into account the possible modifying effect of pubertal stage. Five functional COMT polymorphisms, rs6269, rs4818, rs4680, rs737865 and rs165599 were analysed. Associations between COMT polymorphisms and cognition were tested using regression and latent variable structural equation modelling (SEM). Before correction for multiple testing, COMT rs737865 showed association with reading comprehension, verbal ability and global cognition at age 15 years in pubescent boys only. Although there was some evidence for age- and sex-specific effects of the COMT rs737865 none remained significant after correction for multiple testing. Further studies are necessary in order to make firmer conclusions.

On average, older people remember less and walk more slowly than do younger persons. Some researchers argue that this is due in part to a common biologic process underlying age-related declines in both physical and cognitive functioning. Only recently have longitudinal data become available for analyzing this claim. We conducted a systematic review of English-language research published between 2000 and 2011 to evaluate the relations between rates of change in physical and cognitive functioning in older cohorts. Physical functioning was assessed using objective measures: walking speed, grip strength, chair rise time, flamingo stand time, and summary measures of physical functioning. Cognition was measured using mental state examinations, fluid cognition, and diagnosis of impairment. Results depended on measurement type: Change in grip strength was more strongly correlated with mental state, while change in walking speed was more strongly correlated with change in fluid cognition. Examining physical and cognitive functioning can help clinicians and researchers to better identify individuals and groups that are aging differently and at different rates. In future research, investigators should consider the importance of identifying different patterns and rates of decline, examine relations between more diverse types of measures, and analyze the order in which age-related declines occur.

Background Educational attainment is highly correlated with social inequalities in adult cognitive health; however, the nature of this correlation is in dispute. Recently, researchers have argued that educational inequalities are an artefact of selection by individual differences in prior cognitive ability, which both drives educational attainment and tracks across the rest of the life course. Although few would deny that educational attainment is at least partly determined by prior cognitive ability, a complementary, yet controversial, view is that education has a direct causal and lasting benefit on cognitive development.

Methods We use observational data from three birth cohorts, with cognition measured in adolescence and adulthood. Ordinary least squares regression was used to model the relationship between adolescent cognition and adult fluid cognition and to test the sensitivity of our analyses to sample selection, projection and backdoor biases using propensity score matching.

Results We find that having a university education is correlated with higher fluid cognition in adulthood, after adjustment for adolescent cognition. We do not find that adolescent cognition, gender or parental social class consistently modify this effect; however, women benefited more in the 1946 sample from Great Britain.

Conclusions In all three birth cohorts, substantial educational benefit remained after adjustment for adolescent cognition and parental social class, offsetting an effect equivalent of 0.5 to 1.5 standard deviations lower adolescent cognition. We also find that the likelihood of earning a university degree depends in part on adolescent cognition, gender and parental social class. We conclude that inequalities in adult cognition derive in part from educational experiences after adolescence.

Background

The medical needs of older people are growing because the proportion of the older population is increasing and disease boundaries are widening. This study describes the distribution and clustering of 15 common clinical disorders requiring medical treatment or supervision in a representative British cohort approaching retirement, and how health tracked across adulthood.

Methods and Findings

The data come from a cohort of 2661 men and women, 84% of the target sample, followed since birth in England, Scotland and Wales in 1946, and assessed at 60–64 years for: cardio and cerebro-vascular disease, hypertension, raised cholesterol, renal impairment, diabetes, obesity, hypothyroidism, hyperthyroidism, anaemia, respiratory disease, liver disease, psychiatric problems, cancers, atrial fibrillation on ECG and osteoporosis. We calculated the proportions disorder-free, with one or more disorders, and the level of undiagnosed disorders; and how these disorders cluster into latent classes and relate to health assessed at 36 years. Participants had, on average, two disorders (range 0–9); only 15% were disorder-free. The commonest disorders were hypertension (54.3%, 95% CI 51.8%–56.7%), obesity (31.1%, 28.8%–33.5%), raised cholesterol (25.6%, 23.1–28.26%), and diabetes or impaired fasting glucose (25.0%, 22.6–27.5%). A cluster of one in five individuals had a high probability of cardio-metabolic disorders and were twice as likely than others to have been in the poorest health at 36 years. The main limitations are that the native born sample is entirely white, and a combination of clinical assessments and self reports were used.

Conclusions

Most British people reaching retirement already have clinical disorders requiring medical supervision. Widening disease definitions and the move from a disease-based to a risk-based medical model will increase pressure on health services. The promotion of healthy ageing should start earlier in life and consider the individual's ability to adapt to and self manage changes in health.

Background

Poorer cognitive ability in youth is a risk factor for later mental health problems but it is largely unknown whether cognitive ability, in youth or in later life, is predictive of mental wellbeing. The purpose of this study was to investigate whether cognitive ability at age 11 years, cognitive ability in later life, or lifetime cognitive change are associated with mental wellbeing in older people.

Methods

We used data on 8191 men and women aged 50 to 87 years from four cohorts in the HALCyon collaborative research programme into healthy ageing: the Aberdeen Birth Cohort 1936, the Lothian Birth Cohort 1921, the National Child Development Survey, and the MRC National Survey for Health and Development. We used linear regression to examine associations between cognitive ability at age 11, cognitive ability in later life, and lifetime change in cognitive ability and mean score on the Warwick Edinburgh Mental Wellbeing Scale and meta-analysis to obtain an overall estimate of the effect of each.

Results

People whose cognitive ability at age 11 was a standard deviation above the mean scored 0.53 points higher on the mental wellbeing scale (95% confidence interval 0.36, 0.71). The equivalent value for cognitive ability in later life was 0.89 points (0.72, 1.07). A standard deviation improvement in cognitive ability in later life relative to childhood ability was associated with 0.66 points (0.39, 0.93) advantage in wellbeing score. These effect sizes equate to around 0.1 of a standard deviation in mental wellbeing score. Adjustment for potential confounding and mediating variables, primarily the personality trait neuroticism, substantially attenuated these associations.

Conclusion

Associations between cognitive ability in childhood or lifetime cognitive change and mental wellbeing in older people are slight and may be confounded by personality trait differences.

Background

Lower cognitive ability in childhood is associated with increased risk of future schizophrenia, but its relationship with adult psychotic-like experiences and other psychopathology is less understood.

Aims

To investigate whether this childhood risk factor is shared with adult subclinical psychiatric phenotypes including psychotic-like experiences and general psychiatric morbidity.

Method

A population-based sample of participants born in Great Britain during 1 week in March 1946 was contacted up to 20 times between ages 6 weeks and 53 years. Cognition was assessed at ages 8, 11 and 15 years using a composite of age-appropriate verbal and non-verbal cognitive tests. At age 53 years, psychotic-like experiences were self-reported by 2918 participants using four items from the Psychosis Screening Questionnaire and general psychiatric morbidity was assessed using the scaled version of the General Health Questionnaire (GHQ-28).

Results

Psychotic-like experiences were reported by 22% of participants, and were highly comorbid with other psychopathology. Their presence in adults was significantly associated with poorer childhood cognitive test scores at ages 8 and 15 years, and marginally so at age 11 years. In contrast, high GHQ scores were not associated with poorer childhood cognition after adjustment for the presence of psychotic-like experiences.

Conclusions

Psychotic and non-psychotic psychopathologic symptoms are highly comorbid in the general population. Lower childhood cognitive ability is a risk factor for psychotic-like experiences in mid-life; these phenomena may be one end of a continuum of phenotypic expression driven by variation in early neurodevelopment.

Background

Little is known about the long-term consequences of positive wellbeing in childhood in the general population. We used the MRC National Survey of Health and Development (the British 1946 birth cohort) to test associations between adolescent positive wellbeing and social functioning in midlife.

Method

Temperament and behaviour at ages 13 and 15 years were rated by school teachers on a range of criteria. These mostly referred to absence or presence of conduct and emotional problems, but four items allowed positive ratings: ‘very popular with other children’, ‘unusually happy and contented’, ‘makes friends extremely easily’ and ‘extremely energetic, never tired’. In addition, at age 16 years survey members self-completed the Maudsley Personality Inventory, from which a summary measure of extraversion was derived, as this was previously found to be associated with midlife positive wellbeing in this cohort.

Results

Being a happy child, defined as receiving at least two of the above teacher ratings, was positively associated with midlife functioning and wellbeing, specifically a low probability of lifetime emotional problems, a high frequency of contact with friends or relatives, engagement in social activities, and to a lesser extent feeling satisfied with accomplishments in working life. These associations were independent of father’s social class, childhood cognition, educational attainment, and midlife occupational social class. There were no independent associations between being a happy child and educational or occupational attainment, being married, engagement in prosocial activities, taking leadership in community activities, and with life satisfaction in general or with family life. Extraversion was associated with a low probability of lifetime emotional problems, high engagement in social activities, being married, general midlife life satisfaction, and satisfaction with family life, but not with social contact, prosocial activity, leadership activity, or work satisfaction. While childhood conduct and emotional problems were associated with few of the social and life satisfaction outcomes, the former were negatively associated with educational and occupational attainment, and positively with divorce, whereas the latter were negatively associated with being married.

Conclusions

Prospectively rated childhood wellbeing has long-term beneficial links to adult functioning; our results also support the view that positive wellbeing has a unique impact on these outcomes, and does not merely represent the absence of mental ill-health.

A wide variety of factors across the life course jointly influence cognitive and emotional development. Indeed, research from a variety of disciplines strongly suggests that cognition and mental health are intertwined across the life course, by their common antecedents and underlying physiology in development, and in their interplay across adult and later life. We suggest that cognitive and socio-emotional function fuse to form skills for life supporting self-regulation, competence and quality of life that persist into later life, through linked reciprocal processes of genetic influence, nurturing, schooling, work, and lifestyle.

Purpose

Depersonalization syndrome is characterised by a sense of unreality about the self (depersonalization: DP) and/or the outside world (derealization: DR). Prevalence estimates vary widely. Little is known about childhood antecedents of the disorder although emotional abuse is thought to play a role.

Methods

Longitudinal data from 3275 participants of a UK population based birth cohort (the MRC National Survey of Health and Development) were used to: i) assess the prevalence of DP syndrome at age 36, measured by the Present State Examination (PSE); and ii) examine the effects of a range of socio-demographic, childhood adversity and emotional responses as potential risk factors for DP.

Results

Thirty three survey members were classified with DP, yielding a prevalence of 0.95% (95% confidence intervals (CI) 0.56 to 1.34). There were no associations with socioeconomic status, parental death or divorce; self reported accidents, childhood depression, tendency to daydream or reactions to criticism. However, teacher-estimated childhood anxiety was a strong independent predictor of adult depersonalization, and there were strong cross-sectional relationships between DP and anxiety and depression caseness.

Conclusions

To our knowledge this is the first study assessing nationwide prevalence of the DP syndrome and uses longitudinal data to explore childhood risk factors for adult DP. The prevalence of adult DP was slightly lower than reported by other surveys. The study found that childhood anxiety was the only significant predictor of the adult DP syndrome, supporting the view that depersonalisation disorder forms part of the spectrum of responses to anxiety.

Objectives

The authors aimed to test the relationship between childhood cognitive function and long-term sick leave in adult life and whether any relationship was mediated by educational attainment, adult social class or adult mental ill-health.

Design

Cohort study.

Setting

The authors used data from the 1946, 1958 and 1970 British birth cohorts. Initial study populations included all live births in 1 week in that year. Follow-up arrangements have differed between the cohorts.

Participants

The authors included only those alive, living in the UK and not permanent refusals at the time of the outcome. The authors further restricted analyses to those in employment, full-time education or caring for a family in the sweep immediately prior to the outcome. 2894 (1946), 15 053 (1958) and 14 713 (1970) cohort members were included. Primary and secondary outcome measures: receipt of health-related benefits (eg, incapacity benefit) in 2000 and 2004 for the 1958 and 1970 cohorts, respectively, and individuals identified as ‘permanently sick or disabled’ in 1999 for 1946 cohort.

Results

After adjusting for sex and parental social class, better cognitive function at age 10/11 was associated with reduced odds of being long-term sick (1946: 0.70 (0.56 to 0.86), p=0.001; 1958: 0.69 (0.61 to 0.77), p<0.001; 1970: 0.80 (0.66 to 0.97), p=0.003). Educational attainment appeared to partly mediate the associations in all cohorts; adult social class appeared to have a mediating role in the 1946 cohort.

Conclusions

Long-term sick leave is a complex outcome with many risk factors beyond health. Cognitive abilities might impact on the way individuals are able to develop strategies to maintain their employment or rapidly find new employment when faced with a range of difficulties. Education should form part of the policy response to long-term sick leave such that young people are better equipped with skills needed in a flexible labour market.

Article summary

Article focus

To what extent does cognitive function in childhood predict long-term sick leave.

To what extent might any association be mediated through educational attainment, adult social class or adult mental ill-health.

Key messages

There is a clear dose–response relationship between lower cognitive function in childhood and increased odds of being on long-term sick leave in adulthood.

This association applies to younger as well as older workers and holds true irrespective of the decade of birth.

This association is mediated in part by education attainment suggesting improved education, especially for those with lower cognitive abilities, may help inoculate them from the risk of long-term sickness absence.

Strengths and limitations of this study

Three large birth cohorts with data from across 50 years.

Cohorts broadly representative of the UK population born in that year.

Cognitive function assessed using well-recognised tools.

Different measures of cognitive function, long-term sickness absence and depression used across the cohorts.

Background

Individual differences in personality influence the occurrence, reporting and outcome of mental health problems across the life course, but little is known about the effects on adult psychological well-being. The aim of this study was to examine long range associations between Eysenck’s personality dimensions and psychological well-being in midlife.

Methods

The study sample comprised 1,134 women from the 1946 British birth cohort. Extraversion and neuroticism were assessed using the Maudsley Personality Inventory in adolescence (age 16 years) and early adulthood (age 26). Psychological well-being was assessed at age 52 with a 42-item version of Ryff’s psychological well-being scale. Analyses were undertaken within a structural equation modelling framework that allowed for an ordinal treatment of well-being and personality items, and latent variable modelling of longitudinal data on emotional adjustment. The contribution of mental health problems in linking personality variations to later well-being was assessed using a summary measure of mental health (emotional adjustment) created from multiple time-point assessments.

Results

Women who were more socially outgoing (extravert) reported higher well-being on all dimensions. Neuroticism was associated with lower well-being on all dimensions. The effect of early neuroticism on midlife well-being was almost entirely mediated through emotional adjustment defined in terms of continuities in psychological/ psychiatric distress. The effect of extraversion was not mediated by emotional adjustment, nor attenuated after adjustment for neuroticism.

Conclusions

Individual differences in extraversion and neuroticism in early adult life influence levels of well-being reported in midlife.

Research highlights

► Adolescent emotional problems are a risk factor for metabolic syndrome in mid life. ► CRP gene modifies the association. ► The association is stronger in CRP rs1205 CC homozygotes than in T allele carriers. ► CRP gene helps identifying depressed people at high risk for metabolic syndrome.

Depression is associated with the development of the metabolic syndrome, and both depression and metabolic syndrome are associated with markers of systemic inflammation, such as C-reactive protein (CRP). We examined associations between affective status in adolescence and adulthood, and the metabolic syndrome at age 53 years in a large representative British birth cohort. We also investigated whether two CRP gene polymorphisms (rs1205 and rs3093068) were associated with affective status and the metabolic syndrome, and whether the association between affective status and the metabolic syndrome was modified by these CRP polymorphisms. Women, but not men, with emotional problems in adolescence were more likely to have the metabolic syndrome (OR = 1.53, 95% CI: 1.04, 2.26), although this sex difference was not statistically significant (p = 0.22). The CRP SNPs were not associated with affective status or the metabolic syndrome, but the association of adolescent emotional problems with the metabolic syndrome was stronger in those who were homozygous for the major allele (C) of rs1205 (OR = 1.83, 95% CI: 1.17, 2.86) than in carriers of the T allele (OR = 1.01, 95% CI: 0.66, 1.55) (p = 0.05 for gene by affective status interaction). This interaction was stronger when considering adolescent emotional problems as a continuous variable (p = 0.003). Adolescent emotional problems play an important role in the development of the metabolic syndrome later in life, particularly in those homozygous for the major allele of CRP rs1205. These findings may highlight new ways of identifying people with emotional problems at high risk of developing the metabolic syndrome, which is of great importance for the management of the physical health of these patients.

Background

Vitamin B12 deficiency is common in older people and the prevalence increases with age. Vitamin B12 deficiency may present as macrocytic anaemia, subacute combined degeneration of the spinal cord, or as neuropathy, but is often asymptomatic in older people. The diagnosis and indications for treatment are clear for individuals with low plasma levels of vitamin B12 in the setting of megaloblastic anaemia and neuropathy, but the relevance of treatment of vitamin B12 deficiency in the absence of such clinical signs is uncertain.

Methods

The aim of the present study is to assess whether dietary supplementation with crystalline vitamin B12 will improve electrophysiological indices of neurological function in older people who have biochemical evidence of vitamin B12 insufficiency in the absence of anaemia. To test this hypothesis we designed a randomized double-blind placebo-controlled trial involving 200 older people aged 75 years or greater who were randomly allocated to receive either a daily oral tablet containing 1 mg vitamin B12 or a matching placebo tablet. The primary outcome assessed at 12 months is change in electrophysiological indices of peripheral and central neurosensory responses required for mobility and sensory function. We here report the detailed study protocol.

Conclusions

In view of the high prevalence of vitamin B12 deficiency in later life, the present trial could have considerable significance for public health.

Objectives

To assess differences in cognitive functions by year of birth in Russia and the Czech Republic.

Methods

A cross-sectional study in the general population of Novosibirsk (Russia) and 6 cities of the Czech Republic recruited random samples of men and women (3,874 Russians, 3,626 Czechs) aged 45–69 years in 2002 (i.e. born in 1933–1957). Word recall, verbal fluency (number of animals named in 1 min) and letter search were assessed in a clinic.

Results

Except letter search in men, we found similar levels of cognitive functioning in Russians and Czechs in the youngest subjects and a steeper association of functioning with year of birth in Russia than in the Czech Republic. For example, the difference in the mean word recall, associated with 10 years difference in year of birth, was 0.9 (SE 0.06) words in Russian men, compared to 0.4 (0.06) words in Czech men; in women, these figures were 0.8 (0.05) and 0.3 (0.05), respectively. For all outcomes, except letter search in men, the interactions between year of birth and country were statistically highly significant, and the differences in the year of birth effects between countries were largely unexplained by socioeconomic indicators and risk factors.

Conclusion

The slope of association between lower cognitive functioning and earlier year of birth is much steeper in Russia than in the Czech Republic. Given that poor cognitive functioning is a risk factor for dementia, long-term follow-up of this cohort and other studies into population rates of cognitive impairment in Russia should be a priority.

Objectives

To examine whether measures of cognitive performance across life are related to physical performance at age 53y, allowing for potential confounders.

Methods

In a large representative British birth cohort of men and women the associations between cognitive performance across life (i.e. standardised cognition scores at ages 15, 43 and 53y and changes in verbal memory and search speed scores between 43 and 53y) and measures of physical performance at age 53y (i.e. standing balance, chair rising and grip strength) were examined. Adjustments were made for body size, physical activity levels and health status at age 53y and lifetime socioeconomic conditions.

Results

Higher cognitive scores on all childhood and adult tests, and a slower decline in verbal memory and search speed, were associated with better standing balance. Higher verbal fluency scores and a slower decline in verbal memory and search speed were more strongly related than scores on tests of general cognitive ability to chair rising. The relationships between cognitive performance and grip strength were inconsistent and weak.

Conclusions

The differential patterns of association found are consistent with the degree to which each is dependent upon central nervous system function. Our findings suggest that initial developmental differences as well as common ageing processes may underlie associations found between cognitive and physical performance.

Do bright children grow up to make healthy choices?

IQ in early adulthood has been inversely associated with risk of the metabolic syndrome in midlife. We tested this association in the British 1946 birth cohort, which assessed IQ at age eight years and ascertained the metabolic syndrome at age 53 years based on modified (non-fasting blood) ATPIII criteria. Childhood IQ was inversely associated with risk of the metabolic syndrome, but this association was almost entirely mediated by educational attainment and achieved occupational social class. This may be consistent with a pattern where childhood IQ is strongly associated with outcomes that reflect neurological disorder, such as the degenerative dementias, but less so with common chronic physical diseases of ageing.

Poor childhood and adult socio-economic conditions, lower childhood cognitive ability and cigarette smoking are all associated with adult mortality risk. Using data on 4458 men and women aged 60 years from a British birth cohort study, we investigated the extent to which these risk factors are part of the same pathway linking childhood experience to adult survival. Compared with women from non-manual origins, men from non-manual origins, women and men from manual origins, and those with missing data on father's social class had about double the risk of mortality between 26 and 60 years. Cox proportional hazards models showed that these differences were reduced but remained significant after adjusting for childhood cognitive ability, adult socio-economic conditions and smoking. Higher childhood ability increased survival chances by securing better adult socio-economic conditions, such as home ownership, which was strongly associated with survival. These findings were similar for cardiovascular and cancer mortality.

Objectives. Evidence shows education positively impacts cognitive ability. However, researchers have given little attention to the potential impact of adult education on cognitive ability, still malleable in midlife. The primary study aim was to examine whether there were continuing effects of education over the life course on midlife cognitive ability.

Methods. This study used data from the Medical Research Council National Survey of Health and Development, also known as the British 1946 birth cohort, and multivariate regression to estimate the continuing effects of adult education on multiple measures of midlife cognitive ability.

Results. Educational attainment completed by early adulthood was associated with all measures of cognitive ability in late midlife. The continued effect of education was apparent in the associations between adult education and higher verbal ability, verbal memory, and verbal fluency in late midlife. We found no association between adult education and mental speed and concentration.

Discussion. Associations between adult education and midlife cognitive ability indicate wider benefits of education to health that may be important for social integration, well-being, and the delay of cognitive decline in later life.

We examined whether childhood cognitive ability was associated with two mental health outcomes at age 53 years: the 28 item General Health Questionnaire (GHQ-28) as a measure of internalising symptoms of anxiety and depression, and the CAGE screen for potential alcohol abuse as an externalising disorder. A total of 1875 participants were included from the Medical Research Council National Survey of Health and Development, also known as the British 1946 birth cohort. The results indicated that higher childhood cognitive ability was associated with reporting fewer symptoms of anxiety and depression GHQ-28 scores in women, and increased risk of potential alcohol abuse in both men and women. Results were adjusted for educational attainment, early socioeconomic status (SES) and adverse circumstances, and adult SES, adverse circumstances, and negative health behaviours. After adjusting for childhood cognitive ability, greater educational attainment was associated with reporting greater symptoms of anxiety and depression on the GHQ-28. Although undoubtedly interrelated, our evidence on the diverging effects of childhood cognitive ability and educational attainment on anxiety and depression in mid-adulthood highlights the need for the two to be considered independently. While higher childhood cognitive ability is associated with fewer internalising symptoms of anxiety and depression in women, it places both men and women at higher risk for potential alcohol abuse. Further research is needed to examine possible psychosocial mechanisms that may be associated with both higher childhood cognitive ability and greater risk for alcohol abuse. In addition, the underlying mechanisms responsible for the gender-specific link between childhood cognitive ability and the risk of experiencing internalising disorders in mid-adulthood warrants further consideration.

The number of individuals with age-related cognitive impairment is rising dramatically in the UK and globally. There is considerable interest in the general hypothesis that improving the diet of older people may slow the progression of cognitive decline. To date, there has been little attention given to the possible protective role of n-3 long-chain polyunsaturated fatty acids (n-3 LCPs) most commonly found in oily fish, in age-related loss of cognitive function. The main research hypothesis of this study is that an increased dietary intake of n-3 LCPs will have a positive effect on cognitive performance in older people in the UK.

To test this hypothesis, a double-blind randomised placebo-controlled trial will be carried out among adults aged 70–79 years in which the intervention arm will receive daily capsules containing n-3 LCP (0.5 g/day docosahexaenoic acid and 0.2 g/day eicosapentaenoic acid) while the placebo arm will receive daily capsules containing olive oil. The main outcome variable assessed at 24 months will be cognitive performance and a second major outcome variable will be retinal function. Retinal function tests are included as the retina is a specifically differentiated neural tissue and therefore represents an accessible window into the functioning of the brain.

The overall purpose of this public-health research is to help define a simple and effective dietary intervention aimed at maintaining cognitive and retinal function in later life. This will be the first trial of its kind aiming to slow the decline of cognitive and retinal function in older people by increasing daily dietary intake of n-3 LCPs. The link between cognitive ability, visual function and quality of life among older people suggests that this novel line of research may have considerable public health importance.

Objective To examine the association between cognitive ability in childhood and mid-life cognitive decline in the normal population.

Design Longitudinal, population based, birth cohort study.

Participants 2058 men and women born in 1946.

Main study measures Ability in childhood measured by AH4 and test of verbal comprehension at age 15 years. Ability in adulthood measured by the national adult reading test (NART) at age 53 years. Outcome measures were decline in memory (word list learning) and speed and concentration (timed visual search) from age 43 to 53 years.

Results Ability in childhood was significantly and negatively associated with decline in memory (β = 0.09, P = 0.005, for men; 0.10, P < 0.001, for women) and search speed (β = 0.13, P < 0.001, for men; 0.08, P = 0.01, for women), independent of educational attainment, occupational social class, and a range of health indicators. The adult reading test was also significantly and negatively associated with decline in these outcomes (for memory β = 0.21, P < 0.001, for men; 0.17, P < 0.001, for women; and for search speed β = -0.05 for men; 0.10, P = 0.008 for women) independent of educational attainment, social class, and childhood ability.

Conclusions Ability in childhood can protect against cognitive decline in mid-life and beyond. Results for the adult reading test indicate that the protective effect of ability may also be acquired in adulthood.

Objective

To examine premature mortality in adults in relation to socioeconomic conditions in childhood and adulthood.

Design

Nationally representative birth cohort study with prospective information on socioeconomic conditions.

Setting

England, Scotland, and Wales.

Study members

2132 women and 2322 men born in March 1946 and followed until age 55 years.

Main outcome measures

Deaths between 26 and 54 years of age notified by the NHS central register.

Results

Study members whose father's occupation was manual at age 4, or who lived in the worst housing, or who received the poorest care in childhood had double the death rate during adulthood of those living in the best socioeconomic conditions. All indicators of socioeconomic disadvantage at age 26 years, particularly lack of home ownership, were associated with a higher death rate. Manual origins and poor care in childhood remained associated with mortality even after adjusting for social class in adulthood or home ownership. The hazard ratio was 2.6 (95% confidence interval 1.5 to 4.4) for those living in manual households as children and as adults compared with those living in non-manual households at both life stages. The hazard ratio for those from manual origins who did not own their own home at age 26 years was 4.9 (2.3 to 10.5) compared with those from non-manual origins who were home owners.

Conclusions

Socioeconomic conditions in childhood as well as early adulthood have strongly influenced the survival of British people born in the immediate post war era.

What is already known on this topicAssociations between socioeconomic conditions in childhood and mortality in adulthood suggest that risks to survival begin in early lifeStudies have been generally retrospective, been unrepresentative, used only one marker of childhood conditions, controlled inadequately for adult conditions, or not included womenWhat this study addsThe death rate for women and men between 26 and 54 years living in poor socioeconomic conditions in childhood was double that of those living in the best conditionsThose for whom socioeconomic disadvantage continued into early adulthood were between three and five times more likely to die than those in the most advantageous conditions

Objective

To examine the association between birth weight and cognitive function in the normal population.

Design

A longitudinal, population based, birth cohort study.

Participants

3900 males and females born in 1946.

Main outcome measures

Cognitive function from childhood to middle life (measured at ages 8, 11, 15, 26, and 43 years).

Results

Birth weight was significantly and positively associated with cognitive ability at age 8 (with an estimated standard deviation score of 0.44 (95% confidence interval 0.28 to 0.59)) between the lowest and highest birthweight categories after sex, father's social class, mother's education, and birth order were controlled for. This association was evident across the normal birthweight range (>2.5 kg) and so was not accounted for exclusively by low birth weight. The association was also observed at ages 11, 15, and 26, and weakly at age 43, although these associations were dependent on the association at age 8. Birth weight was also associated with education, with those of higher birth weight more likely to have achieved higher qualifications, and this effect was accounted for partly by cognitive function at age 8.

Conclusions

Birth weight was associated with cognitive ability at age 8 in the general population, and in the normal birthweight range. The effect at this age largely explains associations between birth weight and cognitive function at subsequent ages. Similarly, the association between birth weight and education was accounted for partly by earlier cognitive scores.