Genetic strategies for probing conscientiousness and its relationship to aging

Individuals' contribution to household energy savings: The role of big-two personality traits

Household energy consumption (HEC) is one of the major contributors to global emissions, making it a critical area for addressing sustainability challenges. The impact of personality traits on human behaviour is significant in shaping HEC patterns, and therefore, have important implications for sustainability policies. This study aims to investigate role of biologically predicted big-two personality traits (i.e., stability and plasticity), a higher order solution to five-factor traits and orthogonal traits, on HEC. To that end, a structural equation model is developed using a national household survey in Australia. The performance of the model is benchmarked against a five-factor (i.e., agreeableness, consciousness, emotional stability, extraversion and openness) personality trait model. The performance of the models is measured using six goodness-of-fit indices, all of which show a superior performance in the big-two traits model. The results indicate that a higher score in stability poses energy-intensive behaviour, while a higher plasticity score poses energy-saving behaviours. The plasticity trait is linked to environmentally friendly behaviours, while the stability trait is associated with environmentally unfavourable behavioural practices. The effects of socioeconomic status on HEC are mediated by stability and plasticity to identify those who are more likely to change their energy consumption habits as the target group for policy intervention. This study can assist policy makers to determine energy-intensive and energy-saving behaviours from the big-two traits, and to develop more effective and targeted sustainability policies that can help in reducing HEC and promote sustainable living in societies.

Correlates of Conscientiousness: Findings from the Millennium Cohort Study

This study explored correlates of the trait Conscientiousness drawing on longitudinal data from the Millennium Cohort Study (MCS), with a sample of 7,436 mothers. Data were collected when participants' children were born and again at ages nine months, 3, 11, and 14 years. Structural equation modeling showed that the family poverty indicator, self-esteem, parent-child relationship, children's behavioral problems, and education all had significant and direct effects on maternal trait Conscientiousness. The strongest predictor was self-esteem (measured over 13 years previously), followed by children's behavioral problems and parent-child relationship quality. The implications for helping mothers and their children are considered and limitations are discussed.

Financial strain moderates genetic influences on self-rated health: support for diathesis-stress model of gene-environment interplay

Data from the Interplay of Genes and Environment across Multiple Studies (IGEMS) consortium were used to examine predictions of different models of gene-by-environment interaction to understand how genetic variance in self-rated health (SRH) varies at different levels of financial strain. A total of 11,359 individuals from 10 twin studies in Australia, Sweden, and the United States contributed relevant data, including 2,074 monozygotic and 2,623 dizygotic twin pairs. Age ranged from 22 to 98 years, with a mean age of 61.05 (SD = 13.24). A factor model was used to create a harmonized measure of financial strain across studies and items. Twin analyses of genetic and environmental variance for SRH incorporating age, age², sex, and financial strain moderators indicated significant financial strain moderation of genetic influences on self-rated health. Moderation results did not differ across sex or country. Genetic variance for SRH increased as financial strain increased, matching the predictions of the diathesis-stress and social comparison models for components of variance. Under these models, environmental improvements would be expected to reduce genetically based health disparities.

IGEMS: The Consortium on Interplay of Genes and Environment Across Multiple Studies - An Update

The Interplay of Genes and Environment across Multiple Studies (IGEMS) is a consortium of 18 twin studies from 5 different countries (Sweden, Denmark, Finland, United States, and Australia) established to explore the nature of gene-environment (GE) interplay in functioning across the adult lifespan. Fifteen of the studies are longitudinal, with follow-up as long as 59 years after baseline. The combined data from over 76,000 participants aged 14-103 at intake (including over 10,000 monozygotic and over 17,000 dizygotic twin pairs) support two primary research emphases: (1) investigation of models of GE interplay of early life adversity, and social factors at micro and macro environmental levels and with diverse outcomes, including mortality, physical functioning and psychological functioning; and (2) improved understanding of risk and protective factors for dementia by incorporating unmeasured and measured genetic factors with a wide range of exposures measured in young adulthood, midlife and later life.

[Effect of cytokine genes and season of birth on personality]

AIM

To evaluate the interaction effects of season of birth and immune system genes on the personality traits 'Novelty seeking' (NS) and 'Self-directedness' (SD). Based on results on an influence of the immune system on the brain processes, the authors hypothesized that the interaction of immune system genes and season of birth, which is relevant for immune phenotype, can contribute to the development of personality traits.

MATERIAL AND METHODS

NS and SD were measured in 336 healthy volunteers, aged from 16 to 67 years, using the Temperament and Character Inventory (TCI-125). IL1B C3954T, IL4 C-589T, IL13 C1112T and TNFA G-308A polymorphisms were genotyped.

RESULTS

An interaction effect of IL4 C-589T and season of birth on the personality traits was found (F2,322=6.03, pcorr=0.011, η2=0.04). Carriers of the minor allele T, who were born in winter, had lower NS and higher SD. There was a nominal main effect of genotype on SD (F=5.44, p=0.020) as well, with higher SD scores in carriers of the allele T compared to the CC genotype.

CONCLUSION

The results suggest that the etiology of personality and immune characteristics can share common genetic elements including IL-4.

Facets of Subjective Health From Early Adulthood to Old Age

OBJECTIVE

Subjective health is a complex indicator predicting longevity independent of objective health. Few studies examine genetic and environmental mechanisms underlying different facets of subjective health across the life course.

METHOD

Three subjective health measures were examined in 12,900 twins ( M_age = 63.38, range = 25-102) from nine studies in the Interplay of Genes and Environment across Multiple Studies Consortium: self-rated health (SRH), health compared with others (COMP), and health interfering with activities (ACT).

RESULTS

Analyses indicated age and sex differences in mean scores depending on the measure. SRH and ACT showed significant linear and non-linear moderation by age for individual differences in both genetic and environmental variance. Significant sex differences in components of variance were found for SRH and ACT, but not COMP.

DISCUSSION

Subjective health appears to be dependent on frame of reference and reflect different aspects of health. Results suggest different genetic and environmental mechanisms underlie each facet.

Gender Differences in Marital Status Moderation of Genetic and Environmental Influences on Subjective Health

From the IGEMS Consortium, data were available from 26,579 individuals aged 23 to 102 years on 3 subjective health items: self-rated health (SRH), health compared to others (COMP), and impact of health on activities (ACT). Marital status was a marker of environmental resources that may moderate genetic and environmental influences on subjective health. Results differed for the 3 subjective health items, indicating that they do not tap the same construct. Although there was little impact of marital status on variance components for women, marital status was a significant modifier of variance in all 3 subjective health measures for men. For both SRH and ACT, single men demonstrated greater shared and nonshared environmental variance than married men. For the COMP variable, genetic variance was greater for single men vs. married men. Results suggest gender differences in the role of marriage as a source of resources that are associated with subjective health.

Will interventions targeting conscientiousness improve aging outcomes?

The articles appearing in this special section discuss the role that conscientiousness may play in healthy aging. Growing evidence suggests that conscientious individuals live longer and healthier lives. However, the question remains whether this personality trait can be leveraged to improve long-term health outcomes. We argue that even though it may be possible to design therapeutic interventions that increase conscientiousness, there may be more effective and efficient ways to improve population health. We ask for evidence that a focus on conscientiousness improves behavior change efforts that target specific health-related behaviors or large-scale environmental modification.

Personality plasticity, healthy aging, and interventions

This commentary on the special section on conscientiousness and healthy aging focuses on several topics brought up in this collection of articles. One is the promise of personality interventions. Despite skepticism on the part of some, such interventions may ultimately prove successful. This is in part because of similarities between personality dimensions and cognitive dimensions and in part due to evidence showing personality is more dynamic and plastic than once believed. The commentary concludes with a discussion of the role of longitudinal investigations to inform interventions.