Beverly Roberts

Intelligence in youth and all-cause-mortality: systematic review with meta-analysis

BACKGROUND A number of prospective cohort studies have examined the association between intelligence in childhood or youth and life expectancy in adulthood; however, the effect size of this association is yet to be quantified and previous reviews require updating. METHODS The systematic review included an electronic search of EMBASE, MEDLINE and PSYCHINFO databases. This yielded 16 unrelated studies that met inclusion criteria, comprising 22,453 deaths among 1,107,022 participants. Heterogeneity was assessed, and fixed effects models were applied to the aggregate data. Publication bias was evaluated, and sensitivity analyses were conducted. RESULTS A 1-standard deviation (SD) advantage in cognitive test scores was associated with a 24% (95% confidence interval 23-25) lower risk of death, during a 17- to 69-year follow-up. There was little evidence of publication bias (Eggers intercept = 0.10, P = 0.81), and the intelligence-mortality association was similar for men and women. Adjustment for childhood socio-economic status (SES) in the nine studies containing these data had almost no impact on this relationship, suggesting that this is not a confounder of the intelligence-mortality association. Controlling for adult SES in five studies and for education in six studies attenuated the intelligence-mortality hazard ratios by 34 and 54%, respectively. CONCLUSIONS Future investigations should address the extent to which attenuation of the intelligence-mortality link by adult SES indicators is due to mediation, over-adjustment and/or confounding. The explanation(s) for association between higher early-life intelligence and lower risk of adult mortality require further elucidation.

Stability and change in intelligence from age 11 to ages 70, 79, and 87: the Lothian birth cohorts of 1921 and 1936

Investigating the predictors of age-related cognitive change is a research priority. However, it is first necessary to discover the long-term stability of measures of cognitive ability because prior cognitive ability level might contribute to the amount of cognitive change experienced within old age. These two issues were examined in the Lothian Birth Cohorts of 1921 and 1936. Cognitive ability data were available from age 11 years when the participants completed the Moray House Test No. 12 (MHT). The Lothian Birth Cohort 1936 (LBC1936) completed the MHT a second time at age 70. The Lothian Birth Cohort 1921 (LBC1921) completed the MHT at ages 79 and 87. We examined cognitive stability and change from childhood to old age in both cohorts, and within old age in the LBC1921. Raw stability coefficients for the MHT from 11-70, 11-79, and 11-87 years were .67, .66, and .51, respectively; and larger when corrected for range restriction in the samples. Therefore, minimum estimates of the variance in later-life MHT accounted for by childhood performance on the same test ranged from 26-44%. This study also examined, in the LBC1921, whether MHT score at age 11 influenced the amount of change in MHT between ages 79 and 87. It did not. Higher intelligence from early life was apparently protective of intelligence in old age due to the stability of cognitive function across the lifespan, rather than because it slowed the decline experienced in later life.

Prevalence and Characteristics of Probable Major Depression and Bipolar Disorder within UK Biobank: Cross-Sectional Study of 172,751 Participants

Objectives UK Biobank is a landmark cohort of over 500,000 participants which will be used to investigate genetic and non-genetic risk factors for a wide range of adverse health outcomes. This is the first study to systematically assess the prevalence and validity of proposed criteria for probable mood disorders within the cohort (major depression and bipolar disorder). Methods This was a descriptive epidemiological study of 172,751 individuals assessed for a lifetime history of mood disorder in relation to a range of demographic, social, lifestyle, personality and health-related factors. The main outcomes were prevalence of a probable lifetime (single) episode of major depression, probable recurrent major depressive disorder (moderate), probable recurrent major depressive disorder (severe), probable bipolar disorder and no history of mood disorder (comparison group). Outcomes were compared on age, gender, ethnicity, socioeconomic status, educational attainment, functioning, self-reported health status, current depressive symptoms, neuroticism score, smoking status and alcohol use. Results Prevalence rates for probable single lifetime episode of major depression (6.4%), probable recurrent major depression (moderate) (12.2%), probable recurrent major depression (severe) (7.2%) and probable bipolar disorder (1.3%) were comparable to those found in other population studies. The proposed diagnostic criteria have promising validity, with a gradient in evidence from no mood disorder through major depression and probable bipolar disorder in terms of gender distribution, socioeconomic status, self-reported health rating, current depressive symptoms and smoking. Significance The validity of our proposed criteria for probable major depression and probable bipolar disorder within this cohort are supported by these cross-sectional analyses. Our findings are likely to prove useful as a framework for a wide range of future genetic and non-genetic studies.

Does retirement influence cognitive performance? The Whitehall II Study

Background Occupational work involves many factors capable of protecting cognition. The ‘disuse’ hypothesis suggests that removal of such factors at retirement may increase the risk of cognitive decline. Objective To examine whether retirement is significantly associated with cognitive change after adjusting for preretirement cognitive function, personal, social, health and lifestyle factors, work characteristics and leisure activity. Methods Participants were from the Whitehall II study, a prospective study of London-based Civil Servants. Short-term memory, the AH4 Part 1 (a test of inductive reasoning), verbal fluency and the Mill Hill Vocabulary Scale were collected at ages 38–60 years, and again, on average 5 years later, at 42–67 years, providing pre- and postretirement cognitive functioning assessments for 2031 participants (470 retired and 1561 working). Linear regression was used to test the association between retirement and cognitive performance adjusted for preretirement cognition. Results Mean cognitive test scores increased between the two assessments. However, after adjusting for age, sex, education, occupational social class, Mill Hill score, work characteristics, leisure activities, and indicators of physical and mental health, those retired showed a trend towards smaller test score increases over 5 years than those still working, although this only reached 5% significance in one test (AH4; β=−0.7, 95% CI −1.2 to −0.09) and did not show a dose–response effect with respect to length of time in retirement. Conclusions This trend is consistent with the disuse hypothesis but requires independent replication before it can be accepted as supportive in this respect.

Chronic multisite pain in major depression and bipolar disorder: cross-sectional study of 149,611 participants in UK Biobank

BackgroundChronic pain has a strong association with major depressive disorder (MDD), but there is a relative paucity of studies on the association between chronic multisite pain and bipolar disorder (BD). Such studies are required to help elucidate the complex biological and psychological overlap between pain and mood disorders. The aim of this study is to investigate the relationship between chronic multisite pain and mood disorder across the unipolar-bipolar spectrum.MethodsWe conducted a cross-sectional study of 149,611 UK Biobank participants. Self-reported depressive and bipolar features were used to categorise participants into MDD and BD groups and a non-mood disordered comparison group. Multinomial logistic regression was used to establish whether there was an association between extent of chronic pain (independent variable) and mood disorder category (dependent variable), using no pain as the referent category, and adjusting for a wide range of potential sociodemographic, lifestyle and comorbidity confounders.ResultsMultisite pain was significantly more prevalent in participants with BD and MDD, for example, 4–7 pain sites: BD 5.8%, MDD 4.5%, and comparison group 1.8% (p < 0.001). A relationship was observed between extent of chronic pain and risk of BD and persisted after adjusting for confounders (relative to individuals with no chronic pain): 2–3 sites RRR of BD 1.84 (95% CI 1.61, 2.11); 4–7 sites RRR of BD 2.39 (95% CI 1.88, 3.03) and widespread pain RRR of BD 2.37 (95% CI 1.73, 3.23). A similar relationship was observed between chronic pain and MDD: 2–3 sites RRR of MDD 1.59 (95% CI 1.54, 1.65); 4–7 sites RRR of MDD 2.13 (95% CI 1.98, 2.30); widespread pain RRR of MDD 1.86 (95% CI 1.66, 2.08).ConclusionsIndividuals who report chronic pain and multiple sites of pain are more likely to have MDD and are at higher risk of BD. These findings highlight an important aspect of comorbidity in MDD and BD and may have implications for understanding the shared neurobiology of chronic pain and mood disorders.

Neuroticism and cardiovascular disease mortality: socioeconomic status modifies the risk in women (UK Health and Lifestyle Survey).

Objective The association between personality traits and mortality might differ as a function of socioeconomic status (SES). Our aim was to evaluate the all-cause, cardiovascular disease (CVD), and cancer mortality risk associated with neuroticism or extraversion and their interactions with SES in a representative sample of the UK adult population. Methods A total of 5450 participants (2505 men) from the Health and Lifestyle Survey completed the Eysenck Personality Inventory at baseline and were monitored for vital status over 25 years. SES was defined as a latent variable comprising occupational social class, educational attainment, and income. Results A significant neuroticism-by-SES-by-sex interaction (p = .04) for CVD mortality revealed a neuroticism-by-SES interaction specific to women. Compared to women with average SES, those with both high neuroticism and low SES were at an increased risk for CVD mortality (hazard ratio = 2.02, 95% confidence interval = 1.45–2.80), whereas those with high neuroticism and high SES combined were at a decreased risk for CVD mortality (hazard ratio = 0.61, 95% confidence interval = 0.38–0.97, p for interaction = 0.003). The interaction term was not explained by health behaviors (10% attenuation) and physiological variables (11% attenuation). This interaction was not observed for all-cause and cancer mortality risks or among men for CVD mortality. Conclusions High neuroticism is a risk factor for cardiovascular mortality in women with low SES, whereas in women with higher SES, it is protective. Further research is needed to replicate this finding and identify the mechanisms behind the modifying effect of SES on neuroticism. Abbreviations HALS = Health and Lifestyle Survey CVD = cardiovascular disease EPI = Eysenck Personality Inventory SES = socioeconomic status SD = standard deviation BMI = body mass index FEV1 = forced expiratory volume in 1 second MLR = maximum likelihood with robust standard errors HR = hazard ratio

IQ in late adolescence/early adulthood, risk factors in middle age, and later cancer mortality in men: the Vietnam Experience Study.

Objectives: (i) examine the relation, if any, of pre‐morbid IQ scores at 20 years of age with the risk of later cancer mortality; and (ii) explore the role, if any, of potential mediating factors (e.g. smoking, obesity), assessed in middle age, in explaining the IQ–cancer relation.

Heaviness, health and happiness: a cross-sectional study of 163066 UK Biobank participants

Background Obesity is known to increase the risk of many diseases and reduce overall quality of life. This study examines the relationship with self-reported health (SRH) and happiness. Methods We conducted a cross-sectional study of the 163 066 UK Biobank participants who completed the happiness rating. The association between adiposity and SRH and happiness was examined using logistic regression. SRH was defined as good (excellent, good), or poor (fair, poor). Self-reported happiness was defined as happy (extremely, very, moderately) or unhappy (moderately, very, extremely). Results Poor health was reported by 44 457 (27.3%) participants. The adjusted ORs for poor health were 3.86, 2.92, 2.60 and 6.41 for the highest, compared with lowest, deciles of Body Mass Index, waist circumference, waist to hip ratio and body fat percent, respectively. The associations were stronger in men (p<0.001). Overall, 7511 (4.6%) participants felt unhappy, and only class III obese participants were more likely to feel unhappy (adjusted OR 1.33, 95% CI 1.15 to 1.53, p<0.001) but the associations differed by sex (p<0.001). Among women, there was a significant association between unhappiness and all levels of obesity. By contrast, only class III obese men had significantly increased risk and overweight and class I obese men were less likely to be unhappy. Conclusions Obesity impacts adversely on happiness as well as health, but the association with unhappiness disappeared after adjustment for self-reported health, indicating this may be mediated by health. Compared with obese men, obese women are less likely to report poor health, but more likely to feel unhappy.

Direct and Indirect Pathways Connecting Cognitive Ability With Cardiovascular Disease Risk: Socioeconomic Status and Multiple Health Behaviors

Objective: To model and test direct and indirect pathways connecting general cognitive ability (g) with cardiovascular disease risk factors, via socioeconomic status (SES) and multiple health behaviors. Methods: A sample comprising participants in the Health and Lifestyle Survey, a prospective cohort study of a representative sample of U.K. adults in 1984/5 (n = 4939, 2426 males). Results: Two mediating latent variables were proposed that connected a latent cognitive trait (named g) with a latent trait of cardiovascular disease (CVD) risk: multiple health behaviors (defined by smoking, physical inactivity, and weekly saturated fat intake) and SES (defined by educational attainment, occupational social class, and income). In males and females, SES mediated the association between g and CVD risk, but the mediation was moderated by years of age. A direct effect from g to CVD risk was also significant, but this was restricted to older males. Multiple health behaviors offered no explanatory power, because they were not influenced by g. Conclusions: SES may connect g with CVD risk in males, but not systematically across the life course. Moderated mediation is a novel way to illustrate that direct and indirect pathways can vary as a function of age. Explanations that emphasize g or SES are not mutually exclusive; there are direct and indirect contributions to CVD risk from each source, and these vary across the life course. CHD = coronary heart disease; CVD = cardiovascular disease; g = general cognitive ability; IQ = intelligence quotient; HALS = Health and Lifestyle Survey; NHS = National Health Service; SES = socioeconomic status; WHR = waist/hip ratio.

IQ in childhood and atherosclerosis in middle-age: 40 Year follow-up of the Newcastle Thousand Families Cohort Study.

Objective Carotid intima-media thickness (IMT) is a known precursor to coronary heart disease (CHD) and other relevant health outcomes such as stroke and cognitive impairment. In addition, higher childhood intelligence has been associated with lower risk of coronary heart disease events in later life, although the mechanisms of effect are unclear. We therefore examined the association between childhood intelligence and atherosclerosis using carotid IMT as a marker of the atherosclerotic process. Approach Participants were 412 members of the Newcastle Thousand Families Study, a prospective cohort study of all 1142 births in the city of Newcastle in May and June 1947, who took an IQ test and English and arithmetic tests at age 11 years. Study members participated in a medical examination and lifestyle assessment at age 49–51 years during which IMT was measured using ultrasound techniques. Results Individuals with higher childhood IQ score had a lower mean IMT in middle-age. A standard deviation higher score in childhood overall IQ was associated with a 0.053 mm (95% CI −0.102, −0.004) lower IMT in men and a 0.039 mm (95% CI −0.080, −0.002) lower IMT in women. Similar levels of association were found for the English and arithmetic tests. After adjustment for a range of covariates including education, the size of effect was undiminished in men but increased in women. Conclusions In the present study, higher childhood IQ scores were associated with a lower degree of atherosclerosis by middle-age.