Facets of Conscientiousness and risk of dementia.

BACKGROUND: Multiple studies have found Conscientiousness to be protective against dementia. The purpose of this study is to identify which specific aspects, or facets, of Conscientiousness are most protective against cognitive impairment and whether these associations are moderated by demographic factors and/or genetic risk. METHODS: Health and Retirement Study participants were selected for analysis if they completed the facets of Conscientiousness measure, scored in the range of normal cognitive functioning at the baseline personality assessment, and had at least one follow-up assessment of cognition over the up to 6-year follow-up (N = 11 181). Cox regression was used to test for risk of incident dementia and risk of incident cognitive impairment not dementia (CIND). RESULTS: Over the follow-up, 278 participants developed dementia and 2186 participants developed CIND. The facet of responsibility had the strongest and most consistent association with dementia risk: every standard deviation increase in this facet was associated with a nearly 35% decreased risk of dementia; self-control and industriousness were also protective. Associations were generally similar when controlling for clinical, behavioral, and genetic risk factors. These three facets were also independent predictors of decreased risk of CIND. CONCLUSIONS: The present research indicates that individuals who see themselves as responsible, able to control their behavior, and hard workers are less likely to develop CIND or dementia and that these associations persist after accounting for some common clinical, behavioral, and genetic risk factors.

Temperament and body weight from ages 4 to 15 years.

BACKGROUND/OBJECTIVES: In adulthood, conscientiousness and neuroticism are correlates of body weight and weight gain. The present research examines whether the childhood antecedents of these traits, persistence and negative reactivity, respectively, are associated with weight gain across childhood. We likewise examine sociability as a predictor of childhood weight gain and whether these three traits are associated with weight concerns and weight-management strategies in adolescence. SUBJECTS/METHODS: Participants (N=4153) were drawn from the Longitudinal Study of Australian Children, an ongoing, population-based study of child and family health and well-being. At the baseline assessment, caregivers reported on their child's temperament. At every assessment from ages 4-5 to 14-15 years, study children were weighed and measured by trained staff; there were up to six biennial assessments of body mass index and waist circumference. At ages 14-15 years, study children (n=2975) also self-reported on their weight concerns and weight-management strategies. RESULTS: Study children rated lower in persistence or higher in negative reactivity in early childhood gained more weight between the ages of 4 and 15 years. Sociability was associated with weight gain among girls but not among boys. Lower persistence and higher negative reactivity at ages 4-5 years were also associated with greater weight concerns, restrained eating and use of unhealthy weight-management strategies at ages 14-15 years. CONCLUSIONS: Childhood traits related to conscientiousness and neuroticism are associated with objective weight gain across childhood and with concerns and strategies to manage weight in adolescence. These results are consistent with a lifespan perspective that indicates that trait psychological functioning contributes to health-related markers from childhood through old age.

Caregiver perceptions of childhood weight: demographic moderators and correlates.

BACKGROUND: To examine whether ethnicity moderates the association between caregiver characteristics and perceptions of childhood weight and whether these perceptions are associated with their child's obesity status. METHODS: Caregivers recruited from paediatricians' offices (n = 453) completed a survey about childhood health; nurses weighed and measured the children. Caregivers reported their own weight and height, demographic information about their family and made ratings of healthy weight for children in general and for their own child in particular. RESULTS: African American caregivers were more likely to view heavier girls as healthier, but this association held only for lower income families or caregivers with higher body mass index. Hispanic caregivers were more likely to misperceive their own child's weight if either the caregiver or the child had a higher body mass index. Parents who perceived heavier weight as healthier or misperceived their own child's weight were more likely to have a child with obesity. This latter association held regardless of ethnicity. CONCLUSION: The association between ethnicity and perceptions of healthy childhood weight are complex. The relation between caregivers' perceptions of healthy weight and their own child's obesity status, however, was similar regardless of ethnicity.

FTO genotype and aging: pleiotropic longitudinal effects on adiposity, brain function, impulsivity and diet.

Although overweight and obesity are associated with poor health outcomes in the elderly, the biological bases of obesity-related behaviors during aging are poorly understood. Common variants in the FTO gene are associated with adiposity in children and younger adults as well as with adverse mental health in older individuals. However, it is unclear whether FTO influences longitudinal trajectories of adiposity and other intermediate phenotypes relevant to mental health during aging. We examined whether a commonly carried obesity-risk variant in the FTO gene (rs1421085 single-nucleotide polymorphism) influences adiposity and is associated with changes in brain function in participants within the Baltimore Longitudinal Study of Aging, one of the longest-running longitudinal aging studies in the United States. Our results show that obesity-related risk allele carriers of FTO gene show dose-dependent increments in body mass index during aging. Moreover, the obesity-related risk allele is associated with reduced medial prefrontal cortical function during aging. Consistent with reduced brain function in regions intrinsic to impulse control and taste responsiveness, risk allele carriers of FTO exhibit dose-dependent increments in both impulsivity and intake of fatty foods. We propose that a common neural mechanism may underlie obesity-associated impulsivity and increased consumption of high-calorie foods during aging.

Depressive symptoms are associated with weight gain among women.

BACKGROUND: Many studies have linked depression and obesity; few have more than two assessments of depressive symptoms and adiposity to address the potential bidirectional relationship between adiposity and depressive symptoms from young adulthood through old age. We tested whether baseline depressive symptoms are associated with changes in weight, whether baseline adiposity is associated with changes in depressive symptoms, and whether these associations vary by sex. METHOD: Participants (n=2251; 47% female) were from the Baltimore Longitudinal Study of Aging (BLSA). Using hierarchical linear modeling (HLM) on 30 years of data, the trajectory of adiposity and depressive symptoms over adulthood was estimated from >10 000 observations (mean=4.5 assessments per participant) of body mass index (BMI; kg/m2), waist circumference and hip circumference and >10 000 observations (mean=4.5 assessments per participant) of the Center for Epidemiological Studies Depression Scale (CES-D). Baseline depressive symptoms and adiposity were then tested as predictors of the trajectory of adiposity and depressive symptoms respectively. Additional analyses tested for sex-specific associations. RESULTS: Sex moderated the association between depressive symptoms and weight gain such that women who experienced depressed affect had greater increases in BMI (b(interaction)=0.12, S.E.=0.04), waist (b(interaction)=0.22, S.E.=0.10) and hip circumference (b(interaction)=0.20, S.E.=0.07) across the adult lifespan, controlling for relevant demographic and behavioral covariates. Baseline adiposity was unrelated to the trajectory of depressive symptoms (median b=0.00) for both sexes. CONCLUSIONS: Women who experience symptoms of depression tend to gain more weight across adulthood than men who experience such symptoms. Whether an individual was normal weight or overweight was unrelated to changes in depressive symptoms across adulthood.

Meta-analysis of genome-wide association studies identifies common variants in CTNNA2 associated with excitement-seeking.

The tendency to seek stimulating activities and intense sensations define excitement-seeking, a personality trait akin to some aspects of sensation-seeking. This trait is a central feature of extraversion and is a component of the multifaceted impulsivity construct. Those who score high on measures of excitement-seeking are more likely to smoke, use other drugs, gamble, drive recklessly, have unsafe/unprotected sex and engage in other risky behaviors of clinical and social relevance. To identify common genetic variants associated with the Excitement-Seeking scale of the Revised NEO Personality Inventory, we performed genome-wide association studies in six samples of European ancestry (N=7860), and combined the results in a meta-analysis. We identified a genome-wide significant association between the Excitement-Seeking scale and rs7600563 (P=2 × 10(-8)). This single-nucleotide polymorphism maps within the catenin cadherin-associated protein, alpha 2 (CTNNA2) gene, which encodes for a brain-expressed α-catenin critical for synaptic contact. The effect of rs7600563 was in the same direction in all six samples, but did not replicate in additional samples (N=5105). The results provide insight into the genetics of excitement-seeking and risk-taking, and are relevant to hyperactivity, substance use, antisocial and bipolar disorders.

High neuroticism and low conscientiousness are associated with interleukin-6.

BACKGROUND: High Neuroticism and low Conscientiousness are frequently implicated in health-risk behaviors, such as smoking and overeating, as well as health outcomes, including mortality. Their associations with physiological markers of morbidity and mortality, such as inflammation, are less well documented. The present research examines the association between the five major dimensions of personality and interleukin-6 (IL-6), a pro-inflammatory cytokine often elevated in patients with chronic morbidity and frailty. METHOD: A population-based sample (n=4923) from four towns in Sardinia, Italy, had their levels of IL-6 measured and completed a comprehensive personality questionnaire, the NEO-PI-R. Analyses controlled for factors known to have an effect on IL-6: age; sex; smoking; weight; aspirin use; disease burden. RESULTS: High Neuroticism and low Conscientiousness were both associated with higher levels of IL-6. The findings remained significant after controlling for the relevant covariates. Similar results were found for C-reactive protein, a related marker of chronic inflammation. Further, smoking and weight partially mediated the association between impulsivity-related traits and higher IL-6 levels. Finally, logistic regressions revealed that participants either in the top 10% of the distribution of Neuroticism or the bottom 10% of conscientiousness had an approximately 40% greater risk of exceeding clinically relevant thresholds of IL-6. CONCLUSIONS: Consistent with the literature on personality and self-reported health, individuals high on Neuroticism or low on Conscientiousness show elevated levels of this inflammatory cytokine. Identifying critical medical biomarkers associated with personality may help to elucidate the physiological mechanisms responsible for the observed connections between personality traits and physical health.