Christian Hakulinen

Association of personality with the development and persistence of obesity: a meta-analysis based on individual-participant data.

Personality is thought to affect obesity risk but before such information can be incorporated into prevention and intervention plans, robust and converging evidence concerning the most relevant personality traits is needed. We performed a meta‐analysis based on individual–participant data from nine cohort studies to examine whether broad‐level personality traits predict the development and persistence of obesity (n = 78,931 men and women; mean age 50 years). Personality was assessed using inventories of the Five‐Factor Model (extraversion, neuroticism, agreeableness, conscientiousness and openness to experience). High conscientiousness – reflecting high self‐control, orderliness and adherence to social norms – was associated with lower obesity risk across studies (pooled odds ratio [OR] = 0.84; 95% confidence interval [CI] = 0.80–0.88 per 1 standard deviation increment in conscientiousness). Over a mean follow‐up of 5.4 years, conscientiousness predicted lower obesity risk in initially non‐obese individuals (OR = 0.88, 95% CI = 0.85–0.92; n = 33,981) and was associated with greater likelihood of reversion to non‐obese among initially obese individuals (OR = 1.08, 95% CI = 1.01–1.14; n = 9,657). Other personality traits were not associated with obesity in the pooled analysis, and there was substantial heterogeneity in the associations between studies. The findings indicate that conscientiousness may be the only broad‐level personality trait of the Five‐Factor Model that is consistently associated with obesity across populations.

PERSONALITY AND DEPRESSIVE SYMPTOMS: INDIVIDUAL PARTICIPANT META‐ANALYSIS OF 10 COHORT STUDIES

Personality is suggested to be a major risk factor for depression but large‐scale individual participant meta‐analyses on this topic are lacking.

Personality change associated with chronic diseases: pooled analysis of four prospective cohort studies.

BACKGROUND Common chronic conditions, such as heart disease and cancer, are associated with increased psychological distress, functional limitations and shortened life expectancy, but whether these diseases alter aspects of personality remains unclear. METHOD To examine whether the onset of heart disease, stroke, diabetes, cancer, hypertension, arthritis and respiratory disease is associated with subsequent changes in personality traits of the five-factor model, we pooled data from the Health and Retirement Study, the Midlife in the United States Survey, and the graduate and sibling samples of the Wisconsin Longitudinal Study for an individual-participant meta-analysis (total n=17,493; mean age at baseline 55.8 years). RESULTS After adjustment for age, we observed consistent decreases in extraversion [-0.25 T-scores per one disease; 95% confidence interval (CI) -0.40 to -0.10], emotional stability (-0.40, 95% CI -0.61 to -0.19), conscientiousness (-0.44, 95% CI -0.57 to -0.30) and openness to experience (-0.25, 95% CI -0.37 to -0.13) but not in agreeableness (-0.05, 95% CI -0.19 to 0.08) after the onset of chronic diseases. The onset of each additional chronic disease accelerated the average age-related personality change by 2.5 years in decreasing extraversion, 5.5 years in decreasing conscientiousness, and 1.6 years in decreasing openness to experience, and attenuated the increasing levels of emotional stability by 1.9 years. Co-morbid conditions were associated with larger changes than single diseases, suggesting a dose-response association between morbidity and personality change. CONCLUSIONS These results support the hypothesis that chronic diseases influence personality development in adulthood.

Cumulative Effect of Psychosocial Factors in Youth on Ideal Cardiovascular Health in Adulthood The Cardiovascular Risk in Young Finns Study

Background— The American Heart Association has defined a new metric of ideal cardiovascular health as part of its 2020 Impact Goals. We examined whether psychosocial factors in youth predict ideal cardiovascular health in adulthood. Methods and Results— Participants were 477 men and 612 women from the nationwide Cardiovascular Risk in Young Finns Study. Psychosocial factors were measured from cohorts 3 to 18 years of age at the baseline of the study, and ideal cardiovascular health was examined 27 years later in adulthood. The summary measure of psychosocial factors in youth comprised socioeconomic factors, emotional factors, parental health behaviors, stressful events, self-regulation of the child, and social adjustment of the child. There was a positive association between a higher number of favorable psychosocial factors in youth and greater ideal cardiovascular health index in adulthood (&bgr;=0.16; P<0.001) that persisted after adjustment for age, sex, medication use, and cardiovascular risk factors in childhood (&bgr;=0.15; P<0.001). The association was monotonic, suggesting that each increment in favorable psychosocial factors was associated with improvement in cardiovascular health. Of the specific psychosocial factors, a favorable socioeconomic environment (&bgr;=0.12; P<0.001) and participants’ self-regulatory behavior (&bgr;=0.07; P=0.004) were the strongest predictors of ideal cardiovascular health in adulthood. Conclusions— The findings suggest a dose-response association between favorable psychosocial factors in youth and cardiovascular health in adulthood, as defined by the American Heart Association metrics. The effect seems to persist throughout the range of cardiovascular health, potentially shifting the population distribution of cardiovascular health rather than simply having effects in a high-risk population.

PERSONALITY AND DEPRESSIVE SYMPTOMS: INDIVIDUAL PARTICIPANT META-ANALYSIS OF 10 COHORT STUDIES

Personality is suggested to be a major risk factor for depression but large‐scale individual participant meta‐analyses on this topic are lacking.

A Genome-Wide Approach to Children's Aggressive Behavior: The EAGLE consortium

Individual differences in aggressive behavior emerge in early childhood and predict persisting behavioral problems and disorders. Studies of antisocial and severe aggression in adulthood indicate substantial underlying biology. However, little attention has been given to genome‐wide approaches of aggressive behavior in children. We analyzed data from nine population‐based studies and assessed aggressive behavior using well‐validated parent‐reported questionnaires. This is the largest sample exploring childrens aggressive behavior to date (N = 18,988), with measures in two developmental stages (N = 15,668 early childhood and N = 16,311 middle childhood/early adolescence). First, we estimated the additive genetic variance of childrens aggressive behavior based on genome‐wide SNP information, using genome‐wide complex trait analysis (GCTA). Second, genetic associations within each study were assessed using a quasi‐Poisson regression approach, capturing the highly right‐skewed distribution of aggressive behavior. Third, we performed meta‐analyses of genome‐wide associations for both the total age‐mixed sample and the two developmental stages. Finally, we performed a gene‐based test using the summary statistics of the total sample. GCTA quantified variance tagged by common SNPs (10–54%). The meta‐analysis of the total sample identified one region in chromosome 2 (2p12) at near genome‐wide significance (top SNP rs11126630, P = 5.30 × 10−8). The separate meta‐analyses of the two developmental stages revealed suggestive evidence of association at the same locus. The gene‐based analysis indicated association of variation within AVPR1A with aggressive behavior. We conclude that common variants at 2p12 show suggestive evidence for association with childhood aggression. Replication of these initial findings is needed, and further studies should clarify its biological meaning.

Personality and alcohol consumption: Pooled analysis of 72,949 adults from eight cohort studies

BACKGROUND The role of personality as a determinant of alcohol consumption has long been debated, but prospective evidence is scarce. METHODS We performed individual participant meta-analysis to examine the association between the Five-Factor Model personality traits (extraversion, neuroticism, agreeableness, conscientiousness, and openness to experience) and alcohol consumption using data from eight cohort studies sampled from the USA, UK, Germany, and Australia (total n=72,949; mean age=50 years, 54% female). Alcohol consumption was categorized into abstinence, moderate consumption, and heavy consumption. RESULTS After adjustment for age, sex, and race, higher extraversion (odds ratio for 1 standard deviations increase in the score; 95% confidence interval: 1.14; 1.01-1.29) and lower conscientiousness (0.89; 0.79-1.00) were associated with increased risk of transitioning from moderate to heavy alcohol consumption over time, and also with heavy alcohol consumption. Lower extraversion (0.91; 0.85-0.98), higher agreeableness (1.09; 1.02-1.15), and lower openness (0.90; 0.86-0.95) were associated with increased odds of transitioning from moderate consumption to abstinence as well as with alcohol abstinence. CONCLUSION Findings from this individual-participant meta-analysis suggest that high and increasing alcohol consumption is more common among extraverts and those low on conscientiousness whereas high agreeableness and low openness to experience may increase odds of reducing alcohol consumption and preferring abstinence.

Personality and smoking: individual-participant meta-analysis of nine cohort studies

AIMS To investigate cross-sectional and longitudinal associations between personality and smoking, and test whether socio-demographic factors modify these associations. DESIGN Cross-sectional and longitudinal individual-participant meta-analysis. SETTING Nine cohort studies from Australia, Germany, the United Kingdom and the United States. PARTICIPANTS A total of 79 757 men and women (mean age = 50.8 years). MEASUREMENTS Personality traits of the five-factor model (extraversion, neuroticism, agreeableness, conscientiousness and openness to experience) were used as exposures. Outcomes were current smoking status (current smoker, ex-smoker and never smoker), smoking initiation, smoking relapse and smoking cessation. Associations between personality and smoking were modelled using logistic and multinomial logistic regression, and study-specific findings were combined using random-effect meta-analysis. FINDINGS Current smoking was associated with higher extraversion [odds ratio per 1 standard deviation increase in the score: 1.16; 95% confidence interval (CI) = 1.08-1.24], higher neuroticism (1.19; 95% CI = 1.13-1.26) and lower conscientiousness (95% CI = 0.88; 0.83-0.94). Among non-smokers, smoking initiation during the follow-up period was predicted prospectively by higher extraversion (1.22; 95% CI = 1.04-1.43) and lower conscientiousness (0.80; 95% CI = 0.68-0.93), whereas higher neuroticism (1.16; 95% CI = 1.04-1.30) predicted smoking relapse among ex-smokers. Among smokers, smoking cessation was negatively associated with neuroticism (0.91; 95% CI = 0.87-0.96). Socio-demographic variables did not appear to modify the associations between personality and smoking. CONCLUSIONS Adult smokers have higher extraversion, higher neuroticism and lower conscientiousness personality scores than non-smokers. Initiation into smoking is associated positively with higher extraversion and lower conscientiousness, while relapse to smoking among ex-smokers is associated with higher neuroticism.

Personality and smoking

AIMS To investigate cross-sectional and longitudinal associations between personality and smoking, and test whether socio-demographic factors modify these associations. DESIGN Cross-sectional and longitudinal individual-participant meta-analysis. SETTING Nine cohort studies from Australia, Germany, the United Kingdom and the United States. PARTICIPANTS A total of 79 757 men and women (mean age = 50.8 years). MEASUREMENTS Personality traits of the five-factor model (extraversion, neuroticism, agreeableness, conscientiousness and openness to experience) were used as exposures. Outcomes were current smoking status (current smoker, ex-smoker and never smoker), smoking initiation, smoking relapse and smoking cessation. Associations between personality and smoking were modelled using logistic and multinomial logistic regression, and study-specific findings were combined using random-effect meta-analysis. FINDINGS Current smoking was associated with higher extraversion [odds ratio per 1 standard deviation increase in the score: 1.16; 95% confidence interval (CI) = 1.08-1.24], higher neuroticism (1.19; 95% CI = 1.13-1.26) and lower conscientiousness (95% CI = 0.88; 0.83-0.94). Among non-smokers, smoking initiation during the follow-up period was predicted prospectively by higher extraversion (1.22; 95% CI = 1.04-1.43) and lower conscientiousness (0.80; 95% CI = 0.68-0.93), whereas higher neuroticism (1.16; 95% CI = 1.04-1.30) predicted smoking relapse among ex-smokers. Among smokers, smoking cessation was negatively associated with neuroticism (0.91; 95% CI = 0.87-0.96). Socio-demographic variables did not appear to modify the associations between personality and smoking. CONCLUSIONS Adult smokers have higher extraversion, higher neuroticism and lower conscientiousness personality scores than non-smokers. Initiation into smoking is associated positively with higher extraversion and lower conscientiousness, while relapse to smoking among ex-smokers is associated with higher neuroticism.

Structural and functional aspects of social support as predictors of mental and physical health trajectories: Whitehall II cohort study

Background Social support is associated with better health. However, only a limited number of studies have examined the association of social support with health from the adult life course perspective and whether this association is bidirectional. Methods Participants (n=6797; 30% women; age range from 40 to 77 years) who were followed from 1989 (phase 2) to 2006 (phase 8) were selected from the ongoing Whitehall II Study. Structural and functional social support was measured at follow-up phases 2, 5 and 7. Mental and physical health was measured at five consecutive follow-up phases (3–8). Results Social support predicted better mental health, and certain functional aspects of social support, such as higher practical support and higher levels of negative aspects in social relationships, predicted poorer physical health. The association between negative aspects of close relationships and physical health was found to strengthen over the adult life course. In women, the association between marital status and mental health weakened until the age of approximately 60 years. Better mental and physical health was associated with higher future social support. Conclusions The strength of the association between social support and health may vary over the adult life course. The association with health seems to be bidirectional.