Uncovering the complex genetics of human temperament

Experimental studies of learning suggest that human temperament may depend on the molecular mechanisms for associative conditioning, which are highly conserved in animals. The main genetic pathways for associative conditioning are known in experimental animals, but have not been identified in prior genome-wide association studies (GWAS) of human temperament. We used a data-driven machine learning method for GWAS to uncover the complex genotypic-phenotypic networks and environmental interactions related to human temperament. In a discovery sample of 2149 healthy Finns, we identified sets of single-nucleotide polymorphisms (SNPs) that cluster within particular individuals (i.e., SNP sets) regardless of phenotype. Second, we identified 3 clusters of people with distinct temperament profiles measured by the Temperament and Character Inventory regardless of genotype. Third, we found 51 SNP sets that identified 736 gene loci and were significantly associated with temperament. The identified genes were enriched in pathways activated by associative conditioning in animals, including the ERK, PI3K, and PKC pathways. 74% of the identified genes were unique to a specific temperament profile. Environmental influences measured in childhood and adulthood had small but significant effects. We confirmed the replicability of the 51 Finnish SNP sets in healthy Korean (90%) and German samples (89%), as well as their associations with temperament. The identified SNPs explained nearly all the heritability expected in each sample (37-53%) despite variable cultures and environments. We conclude that human temperament is strongly influenced by more than 700 genes that modulate associative conditioning by molecular processes for synaptic plasticity and long-term memory.

Breastfeeding and offspring's compassion and empathy in adulthood: A study with an over 30-year follow-up

This study investigated whether breastfeeding predicts offspring's dispositional compassion and empathy from early adulthood to middle age. The parents of the participants (N = 1,394) of the Young Finns study answered questions about breastfeeding in 1983, and the participants' compassion and empathy were evaluated in 1997-2012 (participants were aged 20-50 years). Breastfeeding did not predict the course of compassion or empathy in adulthood at the age of 20-50 years. The associations remained non-significant, when adjusted for age, gender, socioeconomic factors, and a wide range of characteristics of the family environment (including mother's gestational age; premature birth; birth weight; number of other children at home; parental mental disorder; parental relationship status; parental postnatal smoking; parental postnatal alcohol use; parenting behavior; and child's externalizing behavior). In conclusion, breastfeeding seems not to predict offspring's compassion or empathy in adulthood. The findings may present a hopeful perspective for children growing up with non-breastfeeding caregivers.

Childhood Psychosocial Environment and Adult Cardiac Health: A Causal Mediation Approach

INTRODUCTION

This study used causal mediation analysis to assess the life-course associations of a favorable childhood psychosocial environment with left ventricular mass and diastolic function in adulthood and the extent to which adult health behaviors mediate these associations.

METHODS

The sample included 880 participants (56% women) from the Young Finns Study with data on the childhood environment from 1980, adult health behaviors (smoking, physical activity, diet, and BMI) from 2001 and an echocardiographic assessment of the left ventricular mass (g/m^2.7) and diastolic function (E/e' ratio; higher values indicating a lower diastolic function) from 2011. The associations of the childhood environment with the left ventricular mass and E/e' ratio and mediation pathways through health behaviors were assessed using marginal structural models that were controlled for age, sex, and time-dependent confounding by adult socioeconomic position (measured as educational attainment) via inverse probability weighting. The data were analyzed in 2018-2019.

RESULTS

The mean age in 2011 was 41 (range 34-49) years. Those above versus below the median childhood score had a 1.28 g/m^2.7 lower left ventricular mass (95% CI= -2.63, 0.07) and a 0.18 lower E/e' ratio (95% CI= -0.39, 0.03). There was no evidence for indirect effects from childhood environments to left ventricular outcomes through adult health behaviors after controlling for time-dependent confounding by the adult socioeconomic position (indirect effect β= -0.30, 95% CI= -1.22, 0.63 for left ventricular mass; β= -0.04, 95% CI= -0.18, 0.11 for E/e' ratio). The results after multiple imputation were similar.

CONCLUSIONS

A favorable childhood environment is associated with more optimal cardiac structure and function in adulthood. After accounting for socioeconomic positions, adult health behaviors explain little of the associations.

Associations Between Early Childcare Environment and Different Aspects of Adulthood Sociability: The 32-Year Prospective Young Finns Study

Sociability is a widely studied trait that has been linked both with individual well- and ill-being. Although early childcare has been shown to affect social competence in children, its role in the development of different aspects of adulthood sociability is poorly understood. Using a longitudinal population-based sample (N = 464), this study investigated whether childcare arrangements at ages 3 or 6 are associated with self-reported adulthood sociability at ages 20 to 35 years. A total of five aspects of sociability were measured using three well-established personality inventories (EAS, NEO-FFI, and TCI). Multilevel modeling was applied to examine the association between early care and adulthood sociability, adjusting for several sources of random variation (between-individual variance, within-individual variance between measurement times, variance between used sociability indicators, and error variance that cannot be attributed to the previously mentioned) and potential confounders (disruptive behavior in childhood, parental socio-economic status, parent–child relationship quality, maternal age, and the number of children in the family). Based on our results, in comparison to home care, family daycare and center-based daycare at age 3 and center-based daycare at age 6 were associated with higher sociability later in life. The association was strongest for aspects of sociability that emphasize the willingness to be surrounded by other people and to be attached to them. In other words, characteristics of early care may contribute uniquely to the development of these aspects of sociability with effects that persist into adult life.

The role of oxytocinergic genes in the intergenerational transmission of parent-child relationship qualities

Parenting qualities are known to transmit across generations, but less is known about genetic processes that may modify how strongly parenting quality carries across generations. We examined in prospective data whether oxytocinergic genes of offspring moderate the intergenerational transmission of warm and accepting parent-child relationship qualities. The sample comprised 1167 Finnish parents (G2, 62% female) and their mothers (G1). At the study baseline, G1 mothers (Mage = 38) reported parent-child relationship qualities towards G2 children (age range 3-18). After 28-34 years, G2 offspring reported parent-child relationship qualities towards their own children using the same questionnaire. A cumulative genetic score was computed for G2 by summing up previously identified four alleles associated with non-optimal parenting or social impairments across OXTR (rs1042778, rs2254298, rs53576) and CD38 (rs3796863) genes. Results indicated no interaction effects of G2 cumulative genetic score on the transmission of parent-child relationship qualities. Among single polymorphisms in OXTR, the interaction effects of rs53576 and rs1042778 were found. G1 maternal emotional warmth was associated with higher G2 emotional warmth among G2 participants with the OXTR rs53576 AA/AG genotype, but not among those with the GG genotype. G1 maternal acceptance was associated with higher G2 acceptance among those G2 participants with the OXTR rs1042778 GG/GT genotype, but not among those with the TT genotype. Oxytocinergic genes may influence sensitivity to quality of parent-child relationship, although this needs replication in future studies.

Socioeconomic position and intergenerational associations of ideal health behaviors

Background

Promoting ideal cardiovascular health behaviors is an objective of the American Heart Association 2020 goals. We hypothesized that ideal health behaviors of parents are associated with health behaviors of their adult offspring, and that higher socioeconomic position in either generation enhances intergenerational associations of ideal health behaviors.

Design

Prospective cohort study.

Methods

We included 1856 Young Finns Study participants who had repeated measurements of socioeconomic position (education, income, occupation), smoking status, body mass index, physical activity and diet from 2001, 2007 and 2011, and data on parental socioeconomic position and health behaviors from 1980. We calculated the total number of ideal behaviors in both generations using American Heart Association definitions. Intergenerational associations were examined using ordinal and linear multilevel regression with random intercepts, in which each participant contributed one, two or three measurements of adult health behaviors (2001, 2007, 2011). All analyses were adjusted for offspring sex, birth year, age, parental education and single parenthood.

Results

Overall, parental ideal health behaviors were associated with ideal behaviors among offspring (odds ratio (OR) 1.28, 95% confidence interval 1.17, 1.39). Furthermore, ORs for these intergenerational associations were greater among offspring whose parents or who themselves had higher educational attainment (OR 1.56 for high vs. OR 1.19 for low parental education; P = 0.01 for interaction, OR 1.32 for high vs. OR 1.04 for low offspring education; P = 0.02 for interaction). Similar trends were seen with parental income and offspring occupation. Results from linear regression analyses were similar.

Conclusions

These prospective data suggest higher socioeconomic position in parents or in their adult offspring strengthens the intergenerational continuum of ideal cardiovascular health behaviors.

Gene-environment correlations in parental emotional warmth and intolerance: genome-wide analysis over two generations of the Young Finns Study

BACKGROUND

Genomic analysis of the child might offer new potential to illuminate human parenting. We examined whether offspring (G2) genome-wide genotype variation (SNPs) is associated with their mother's (G1) emotional warmth and intolerance, indicating a gene-environment correlation. If this association is stronger than between G2's genes and their emotional warmth and intolerance toward their own children, then this would indicate the presence of an evocative gene-environment correlation. To further understand how G1 mother's parenting has been evoked by genetically influenced characteristics of the child (G2), we examined whether child (G2) temperament partially accounted for the association between offspring genes and parental responses.

METHODS

Participants were from the Young Finns Study. G1 mothers (N = 2,349; mean age 39 years) self-reported the emotional warmth and intolerance toward G2 in 1980 when the participants were from 3 to 18 years old. G2 participants answered the same parenting scales in 2007/2012 (N = 1,378; mean age = 38 years in 2007; 59% female) when their children were on average 11 years old. Offspring temperament traits were self-reported in 1992 (G2 age range 15-30 years). Estimation of the phenotypic variance explained by the SNPs of G2 was done by genome-wide complex trait analysis with restricted maximum likelihood (GCTA-GREML).

RESULTS

Results showed that the SNPs of a child (G2) explained 22.6% of the phenotypic variance of maternal intolerance (G1; p-value = .039). G2 temperament trait negative emotionality explained only 2.4% points of this association. G2 genes did not explain G1 emotional warmth or G2's own emotional warmth and intolerance. However, further analyses of a combined measure of both G1 parenting scales found genetic effects. Parent or child gender did not moderate the observed associations.

CONCLUSIONS

Presented genome-wide evidence is pointing to the important role a child plays in affecting and shaping his/her family environment, though the underlying mechanisms remain unclear.

Physical Activity, Sleep, and Symptoms of Depression in Adults-Testing for Mediation

PURPOSE

Physical activity, sleep problems, and symptoms of depression contribute to overall well-being. The factors are reciprocally associated, but the nature of these associations remains unclear. The present study examined whether sleep problems mediated the association between physical activity and depressive symptoms.

METHODS

The eligible population (n = 3596) consisted of adults from the ongoing, population-based Cardiovascular Risk in Young Finns Study started in 1980. Participants' leisure-time physical activity was assessed with physical activity index (2007) and sleep problems with Jenkins' Sleep Questionnaire in 2007 and 2011. Depressive symptoms were measured using modified Beck Depression Inventory in 2007 and 2012, from which the items reflecting sleep problems were excluded. Mediation analyses, through which the associations between the variables were examined, were adjusted for sex and a set of health-related covariates assessed in 2007 and 2011.

RESULTS

Physical activity was associated with decreased levels of sleep problems and depressive symptoms (P < 0.05). The association between physical activity and depressive symptoms (b = -0.10, P < 0.01) was partly mediated by sleep problems (proportion mediated = 0.36, P < 0.01). The adjustment for depressive symptoms at baseline attenuated the mediation effect (proportion mediated = 0.30, P > 0.05).

CONCLUSIONS

Physical activity's favorable contribution to depressive symptoms was mediated partly by sleep, but the mediation effect disappeared after adjusting for the previous depressive symptoms in adulthood.

Parent-child-relationship quality predicts offspring dispositional compassion in adulthood: A prospective follow-up study over three decades

Compassion is known to predict prosocial behavior and moral judgments related to harm. Despite the centrality of compassion to social life, factors predicting adulthood compassion are largely unknown. We examined whether qualities of parent-child-relationship, namely, emotional warmth and acceptance, predict offspring compassion decades later in adulthood. We used data from the prospective population-based Young Finns Study. Our sample included 2,761 participants (55.5% women). Parent-child-relationship qualities were reported by each participant's parents at baseline in 1980 (T0) when participants were between 3 and 18 years old. Compassion was self-reported 3 times: in 1997 (T1), 2001 (T2), and 2012 (T3) with the Temperament and Character Inventory (Cloninger, Przybeck, Svrakic, & Wetzel, 1994). By using age at the assessment as a time-variant variable, we applied multilevel modeling for repeated measurements to examine developmental trajectories of compassion from the ages of 20 (the age of the youngest cohort at T1) to 50 (the age of the oldest cohort at T3). On average, compassion increased in a curvilinear pattern with age. Higher acceptance (p = .013) and higher emotional warmth (p < .001) were related to higher compassion in adulthood. After adjusting for childhood confounds (i.e., participant gender, birth cohort, externalizing behavior, parental socioeconomic status, and parental mental health problems), only emotional warmth (p < .001) remained a significant predictor of compassion. Quality of the parent-child-relationship has long-term effects on offspring compassion. An emotionally warm and close relationship, in particular, may contribute to higher offspring compassion in adulthood. (PsycINFO Database Record (c) 2018 APA, all rights reserved).

A Longitudinal Multilevel Study of the "Social" Genotype and Diversity of the Phenotype

Sociability and social domain-related behaviors have been associated with better well-being and endogenous oxytocin levels. Inspection of the literature, however, reveals that the effects between sociability and health outcomes, or between sociability and genotype, are often weak or inconsistent. In the field of personality psychology, the social phenotype is often measured by error-prone assessments based on different theoretical frameworks, which can partly explain the inconsistency of the previous findings. In this study, we evaluated the generalizability of “sociability” measures by partitioning the population variance in adulthood sociability using five indicators from three personality inventories and assessed in two to four follow-ups over a 15-year period (n = 1,573 participants, 28,323 person-observations; age range 20–50 years). Furthermore, we tested whether this variance partition would shed more light to the inconsistencies surrounding the “social” genotype, by using four genetic variants (rs1042778, rs2254298, rs53576, rs3796863) previously associated with a wide range of human social functions. Based on our results, trait (between-individual) variance explained 23% of the variance in overall sociability, differences between sociability indicators explained 41%, state (within-individual) variance explained 5% and measurement errors explained 32%. The genotype was associated only with the sociability indicator variance, suggesting it has specific effects on sentimentality and emotional sharing instead of reflecting general sociability.

Does education protect against depression? Evidence from the Young Finns Study using Mendelian randomization

Using participants (N = 1733) drawn from the nationally representative longitudinal Young Finns Study (YFS) we estimate the effect of education on depressive symptoms. In 2007, when the participants were between 30 and 45 years old, they reported their depressive symptoms using a revised version of Beck's Depression Inventory. Education was measured using register information on the highest completed level of education in 2007, which was converted to years of education. To identify a causal relationship between education and depressive symptoms we use an instrumental variables approach (Mendelian randomization, MR) with a genetic risk score as an instrument for years of education. The genetic risk score was based on 74 genetic variants, which were associated with years of education in a genome-wide association study (GWAS). Because the genetic variants are randomly assigned at conception, they induce exogenous variation in years of education and thus identify a causal effect if the assumptions of the MR approach are met. In Ordinary Least Squares (OLS) estimation years of education in 2007 were negatively associated with depressive symptoms in 2007 (b = -0.027, 95% Confidence Interval (CI) = -0.040, -0.015). However, the results based on Mendelian randomization suggested that the effect is not causal (b = 0.017; 95% CI = -0.144, 0.178). This indicates that omitted variables correlated with education and depression may bias the linear regression coefficients and exogenous variation in education caused by differences in genetic make-up does not seem to protect against depressive symptoms.

Oxytocin receptor gene (OXTR) variant rs1042778 moderates the influence of family environment on changes in perceived social support over time

BACKGROUND

Lack of social support is an established risk factor across health outcomes, making it important to examine its family environmental and genetic determinants.

METHODS

In a 27-year follow-up of the Young Finns Study (N = 2341), we examined with a latent growth curve model whether genes involved in the oxytocin signaling pathway-namely, oxytocin receptor gene (OXTR) variants rs1042778, rs2254298, and rs53576-moderate the effect of early-life social experiences on perceived social support across the life span. Mothers reported the emotional warmth and acceptance towards their children at baseline when the participants were from 3 to 18 years old (1980). Perceived family support and support from friends and peripheral sources were assessed in five follow-ups 18 years apart (1989-2007).

RESULTS

Maternal emotional warmth and acceptance predicted the initial level of perceived social support across subscales, while the rate of change in family support was affected by the family environment only if participants carried the T-allele of OXTR rs1042778. This gene-environment interaction was not found for the rate of change in support from friends and peripheral sources and we also did not find associations between latent growth in perceived social support and OXTR variants rs53576 and rs2254298.

LIMITATIONS

Selective attrition in perceived social support, maternal emotional warmth and acceptance, gender, and SES. Family environment was assessed by a non-standardized measure.

CONCLUSIONS

OXTR rs1042778 polymorphism seems to contribute to changes in perceived family support in that way that some individuals (T-allele carriers) 'recover', to some extent, from the effects of early-life social experiences, whereas others (G/G genotype carriers) do not.

Is the association between depressive symptoms and glucose bidirectional? A population-based study

OBJECTIVE

Depressive symptoms have been associated with Type 2 diabetes, but the temporal direction of this association and the underlying mechanisms remain unclear. The present study examined a potential bidirectional association between depressive symptoms and glucose levels in women and men, and the factors mediating this association.

METHOD

The participants were from the Cardiovascular Risk in Young Finns Study, a prospective, population-based, cohort study (N = 2,534). Depressive symptoms were assessed using a modified Beck Depression Inventory. Fasting glucose was measured concurrently with depressive symptoms. To analyze the data, a multiple-group cross-lagged analysis and parallel multiple mediation in structural equation modeling were used.

RESULTS

Depressive symptoms in 2001 were positively associated with glucose levels in 2012 in women (β = .07, p = .023) but not in men (β = -.03, p = .45). This sex difference was statistically significant (p = .042). Glucose levels in 2001 did not predict depressive symptoms in 2012 in either women or men (ps = .96). Changes in body mass index, high-sensitivity C-reactive protein, alcohol consumption, or tobacco or cigarette smoking did not mediate the observed association (ps > .05).

CONCLUSIONS

The results showed a positive association between depressive symptoms and glucose levels in women but not in men. The direction of this relationship seems to be from depressive symptoms to glucose levels rather than the reverse. Changes in body fat, inflammation, alcohol consumption, or tobacco or cigarette smoking may not play a mediating role in this observed association. (PsycINFO Database Record

A network approach to the analysis of psychosocial risk factors and their association with health

We modeled early psychosocial risks as a network of interconnected variables to study their associations with later depressive symptoms and cardiometabolic outcomes. The participants were a nationally representative sample of 2580 men and women aged 3-18 years in 1980. Their parents reported the psychosocial risks in 1980, including the following: (1) child-specific life events, (2) parental health behavior, (3) parental socioeconomic status, and (4) parental psychological problems. Adulthood depressive symptoms and cardiometabolic outcomes were measured in 2007-2012. The most central risks (most number of connections to other risks) were socioeconomic risks that also predicted health outcomes more consistently than others.

Social isolation and loneliness as risk factors for myocardial infarction, stroke and mortality: UK Biobank cohort study of 479 054 men and women

OBJECTIVE

To examine whether social isolation and loneliness (1) predict acute myocardial infarction (AMI) and stroke among those with no history of AMI or stroke, (2) are related to mortality risk among those with a history of AMI or stroke, and (3) the extent to which these associations are explained by known risk factors or pre-existing chronic conditions.

METHODS

Participants were 479 054 individuals from the UK Biobank. The exposures were self-reported social isolation and loneliness. AMI, stroke and mortality were the outcomes.

RESULTS

Over 7.1 years, 5731 had first AMI, and 3471 had first stroke. In model adjusted for demographics, social isolation was associated with higher risk of AMI (HR 1.43, 95% CI 1.3 to -1.55) and stroke (HR 1.39, 95% CI 1.25 to 1.54). When adjusted for all the other risk factors, the HR for AMI was attenuated by 84% to 1.07 (95% CI 0.99 to 1.16) and the HR for stroke was attenuated by 83% to 1.06 (95% CI 0.96 to 1.19). Loneliness was associated with higher risk of AMI before (HR 1.49, 95% CI 1.36 to 1.64) but attenuated considerably with adjustments (HR 1.06, 95% CI 0.96 to 1.17). This was also the case for stroke (HR 1.36, 95% CI 1.20 to 1.55 before and HR 1.04, 95% CI 0.91 to 1.19 after adjustments). Social isolation, but not loneliness, was associated with increased mortality in participants with a history of AMI (HR 1.25, 95% CI 1.03 to 1.51) or stroke (HR 1.32, 95% CI 1.08 to 1.61) in the fully adjusted model.

CONCLUSIONS

Isolated and lonely persons are at increased risk of AMI and stroke, and, among those with a history of AMI or stroke, increased risk of death. Most of this risk was explained by conventional risk factors.

The co-occurrence between depressive symptoms and paranoid ideation: A population-based longitudinal study

BACKGROUND

The aim of this study was to examine longitudinally in the general population (a) whether depressive symptoms co-occur with paranoid ideation from late adolescence to middle age (b) whether depressive subsymptoms are differently linked with paranoid ideation (c) whether depressive symptoms are associated with state-level or trait-level paranoid ideation.

METHODS

Altogether 2109 subjects of the Young Finns study completed the Paranoid Ideation Scale of the Symptom Checklist-90 Revised and a modified version of the Beck Depression Inventory in 1992, 1997, 2001, 2007, and 2012, and the Beck Depression Inventory-II in 2007, 2011, and 2012.

RESULTS

Higher self-rated depressive symptoms were associated with the course of more severe paranoid ideation over age, especially in late adolescence and early adulthood. Regarding depressive subsymptoms, the associations of negative attitude and performance difficulties with paranoid ideation were evident over age, whereas the influence of somatic symptoms (such as changes in sleep and appetite) was not significant until after early adulthood. Additionally, depressive symptoms were more evidently associated with the development of trait- than state-level paranoid ideation.

LIMITATIONS

Our study mostly captured mild depressive and paranoid symptoms. The results cannot be directly generalized to clinical populations.

CONCLUSIONS

Depressive symptoms were associated with the course of paranoid ideation from late adolescence to middle age. Patients with paranoid ideation might merit from evaluation of potential depressive symptoms, especially in late adolescence and early adulthood. Among patients with co-occurring depressive symptoms and paranoid ideation, there may be a substantial need for neurocognitive rehabilitation and community-based treatments.

Longitudinal associations of temperament and character with paranoid ideation: A population-based study

The aim of this study was to examine (a) the associations of temperament and character dimensions with paranoid ideation over a 15-year follow-up in the general population (b) the associations of explosive temperament and organized character profiles with paranoid ideation. 2137 subjects of the Young Finns Study completed the Temperament and Character Inventory and the Paranoid Ideation Scale of the Symptom Checklist-90 Revised in 1997, 2001, and 2012. Temperament dimensions of high novelty seeking, high harm avoidance, low reward dependence and explosive temperament profile were associated with the development of higher paranoid ideation. Regarding character, high self-directedness, high cooperativeness, and low self-transcendence and organized character profile were associated with lower paranoid ideation. These associations sustained after controlling for age, gender, and socioeconomic factors. However, the associations between temperament and paranoia mostly disappeared after taking character into account. Our study supported the hypothesis that personality dimensions contribute to the development of paranoid ideation. Temperament and character might combine a variety of single previously found risk factors into a more comprehensive framework for the developmental etiology of paranoia. Our findings provide evidence for psychotherapeutic interventions that support the self-regulation of temperamental vulnerabilities by internalizing mature concepts about the self and social relationships.

Structural social relations and cognitive ageing trajectories: evidence from the Whitehall II cohort study

BACKGROUND

Social relations are important for health, particularly at older ages. We examined the salience of frequency of social contacts and marital status for cognitive ageing trajectories over 21 years, from midlife to early old age.

METHODS

Data are from the Whitehall II cohort study, including 4290 men and 1776 women aged 35-55 years at baseline (1985-88). Frequency of social contacts and marital status were measured in 1985-88 and 1989-90. Assessment of cognitive function on five occasions (1991-94, 1997-99, 2003-04, 2007-09 and 2012-13) included the following tests: short-term memory, inductive reasoning, verbal fluency (phonemic and semantic) and a combined global score. Cognitive trajectories over the study period were analysed using longitudinal latent growth class analyses, and the associations of these latent classes (trajectory memberships) with social relations were analysed using multinominal logistic regression.

RESULTS

More frequent social contacts [relative risk (RRR) 0.96, 95% confidence interval (CI) 0.94 - 0.98] and being married (RRR 0.70, 95% CI 0.58 - 0.84) were associated with lower probability of being on a low rather than high cognitive performance trajectory over the subsequent 21 years. These associations persisted after adjustment for covariates. Of the sub-tests, social relations variables had the strongest association with phonemic fluency (RRR 0.95, 95% CI 0.94 - 0.97 for frequent contact; RRR 0.59, 95% CI 0.48 - 0.71 for being married).

CONCLUSIONS

More frequent social contacts and having a spouse were associated with more favourable cognitive ageing trajectories. Further studies are needed to examine whether interventions designed to improve social connections affect cognitive ageing.

Does high optimism protect against the inter-generational transmission of high BMI? The Cardiovascular Risk in Young Finns Study

OBJECTIVE

The transmission of overweight from one generation to the next is well established, however little is known about what psychosocial factors may protect against this familial risk. The aim of this study was to examine whether optimism plays a role in the intergenerational transmission of obesity.

METHODS

Our sample included 1043 participants from the prospective Cardiovascular Risk in Young FINNS Study. Optimism was measured in early adulthood (2001) when the cohort was aged 24-39years. BMI was measured in 2001 (baseline) and 2012 when they were aged 35-50years. Parental BMI was measured in 1980. Hierarchical linear regression and logistic regression were used to examine the association between optimism and future BMI/obesity, and whether an interaction existed between optimism and parental BMI when predicting BMI/obesity 11years later.

RESULTS

High optimism in young adulthood demonstrated a negative relationship with high BMI in mid-adulthood, but only in women (β=-0.127, p=0.001). The optimism×maternal BMI interaction term was a significant predictor of future BMI in women (β=-0.588, p=0.036). The logistic regression results confirmed that high optimism predicted reduced obesity in women (OR=0.68, 95% CI, 0.55-0.86), however the optimism × maternal obesity interaction term was not a significant predictor (OR=0.50, 95% CI, 0.10-2.48).

CONCLUSIONS

Our findings supported our hypothesis that high optimism mitigated the intergenerational transmission of high BMI, but only in women. These findings also provided evidence that positive psychosocial factors such as optimism are associated with long-term protective effects on BMI in women.

Childhood Socioeconomic Status and Arterial Stiffness in Adulthood: The Cardiovascular Risk in Young Finns Study

Increasing evidence supports the importance of socioeconomic factors in the development of atherosclerotic cardiovascular disease. However, the association of childhood socioeconomic status (SES) with arterial stiffness in adulthood has not been reported. Our aim was to determine whether higher childhood family-level SES is associated with lower arterial stiffness in adulthood. The analyses were performed using data gathered within the longitudinal Young Finns Study. The sample comprised 2566 participants who had data concerning family SES at ages 3 to 18 years in 1980 and arterial pulse wave velocity and carotid artery distensibility measured 21 or 27 years later in adulthood. Higher family SES in childhood was associated with lower arterial stiffness in adulthood; carotid artery distensibility being higher (β value±SE, 0.029±0.0089%/10 mm Hg; P=0.001) and pulse wave velocity lower (β value±SE, -0.062±0.022 m/s; P=0.006) among those with higher family SES in a multivariable analysis adjusted with age, sex, and conventional childhood cardiometabolic risk factors. The association remained significant after further adjustment for participant's SES in adulthood (β value±SE, 0.026±0.010%/10 mm Hg; P=0.01 for carotid artery distensibility and β value±SE, -0.048±0.023 m/s; P=0.04 for pulse wave velocity) but attenuated after adjustment for adulthood cardiometabolic risk factors (β value±SE, 0.015±0.008%/10 mm Hg; P=0.08 for carotid artery distensibility and β value±SE, -0.019±0.02 m/s; P=0.38 for pulse wave velocity). In conclusion, we observed an association between higher family SES in childhood and lower arterial stiffness in adulthood. Our findings suggest that special attention could be paid to children from low SES families to prevent cardiometabolic diseases primordially.

Fasting Glucose and the Risk of Depressive Symptoms: Instrumental-Variable Regression in the Cardiovascular Risk in Young Finns Study

PURPOSE

Type 2 diabetes (T2D) has been associated with depressive symptoms, but the causal direction of this association and the underlying mechanisms, such as increased glucose levels, remain unclear. We used instrumental-variable regression with a genetic instrument (Mendelian randomization) to examine a causal role of increased glucose concentrations in the development of depressive symptoms.

METHOD

Data were from the population-based Cardiovascular Risk in Young Finns Study (n = 1217). Depressive symptoms were assessed in 2012 using a modified Beck Depression Inventory (BDI-I). Fasting glucose was measured concurrently with depressive symptoms. A genetic risk score for fasting glucose (with 35 single nucleotide polymorphisms) was used as an instrumental variable for glucose.

RESULTS

Glucose was not associated with depressive symptoms in the standard linear regression (B = -0.04, 95% CI [-0.12, 0.04], p = .34), but the instrumental-variable regression showed an inverse association between glucose and depressive symptoms (B = -0.43, 95% CI [-0.79, -0.07], p = .020). The difference between the estimates of standard linear regression and instrumental-variable regression was significant (p = .026) CONCLUSION: Our results suggest that the association between T2D and depressive symptoms is unlikely to be caused by increased glucose concentrations. It seems possible that T2D might be linked to depressive symptoms due to low glucose levels.