Mirka Hintsanen

Job strain and early atherosclerosis: The cardiovascular risk in young Finns study

Objective: The purpose of this study was to determine whether job strain and social support are associated with early atherosclerosis measured by carotid intima-media thickness (IMT) in young adults. Methods: The subjects were 478 men and 542 women (mean age 32.3) who were participating in the ongoing prospective Cardiovascular Risk in Young Finns study. Job strain was defined as a joint effect of job demands and job control. Early atherosclerosis was determined with IMT ultrasound. The associations between job strain, social support, and IMT were evaluated using multiple linear regressions. Results: In men, job strain was associated with increased IMT after adjustment for age. This association was not attenuated by additional adjustment for established risk factors of coronary heart disease. In women, job strain was not associated with IMT. No 3-way interaction of job demand, job control, and social support on IMT was found. Conclusion: These findings suggest that job strain may be related to atherosclerosis already in its early nonsymptomatic stages in men. BMI = body mass index; CHD = coronary heart disease; CRYF = Cardiovascular Risk in Young Finns; HDL = high-density lipoprotein; IMT = intima-media thickness; LDL = low-density lipoprotein; OSQ = Occupational Stress Questionnaire; PAI = physical activity index; SES = socioeconomic status.

Maturity and change in personality: Developmental trends of temperament and character in adulthood

We studied the developmental trends of temperament and character in a longitudinal population-based sample of Finnish men and women aged 20-45 years using the Temperament and Character Inventory model of personality. Personality was assessed in 1997, 2001, and 2007 (n = 2,104, 2,095, and 2,056, respectively). Mean-level changes demonstrated qualitatively distinct developmental patterns for character (self-directedness, cooperativeness, and self-transcendence) and temperament (novelty seeking, harm avoidance, reward dependence, and persistence). Character developed toward greater maturity, although self-transcendence decreased with age. However, self-transcendence was the strongest predictor of overall personality change. Cohort effects indicated lower level of self-transcendence and higher level of self-directedness and cooperativeness in younger birth cohorts. Regarding temperament, novelty seeking decreased and persistence increased slightly with age. Both high novelty seeking and high persistence predicted overall personality change. These findings suggest that temperament and character traits follow different kinds of developmental trajectories.

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.

Shift work in young adults and carotid artery intima-media thickness: The Cardiovascular Risk in Young Finns study

OBJECTIVE Shift work is associated with an elevated risk of cardiovascular disease, but the timing or mechanisms of this association is unclear. METHODS AND RESULTS We examined the relationship between shift work and subclinical atherosclerosis in 1543 (712 men and 831 women, 24-39 years old) young adults as part of the ongoing population-based Cardiovascular Risk in Young Finns study. Carotid atherosclerosis was assessed by measuring the thickness of the common carotid artery intima-media (IMT) complex with ultrasound and carotid plaque. Working schedules were categorized as day work or shift work (2- or 3-shift work, regular evening or night work). In men, shift work was associated with higher mean IMT (B=0.029, p=0.021), maximum IMT (B=0.029, p=0.028), and a 2.2-fold odds of carotid plaque (95% CI, 1.2-4.0). These relationships persisted after adjustment for age and risk factors, such as low socio-economic position, job strain, smoking, diet, family history of CHD, physical inactivity, alcohol consumption, obesity, homocysteine, C-reactive protein, blood pressure, and lipids. In women, no association was found between shift work and carotid atherosclerosis indicators. CONCLUSIONS Our results suggest that shift work accelerates the atherosclerotic process and that the effects of shift work on subclinical atherosclerosis are observable in men already before age 40.

Maintenance of genetic variation in human personality: Testing evolutionary models by estimating heritability due to common causal variants and investigating the effect of distant inbreeding

Personality traits are basic dimensions of behavioral variation, and twin, family, and adoption studies show that around 30% of the between‐individual variation is due to genetic variation. There is rapidly growing interest in understanding the evolutionary basis of this genetic variation. Several evolutionary mechanisms could explain how genetic variation is maintained in traits, and each of these makes predictions in terms of the relative contribution of rare and common genetic variants to personality variation, the magnitude of nonadditive genetic influences, and whether personality is affected by inbreeding. Using genome‐wide single nucleotide polymorphism (SNP) data from > 8000 individuals, we estimated that little variation in the Cloninger personality dimensions (7.2% on average) is due to the combined effect of common, additive genetic variants across the genome, suggesting that most heritable variation in personality is due to rare variant effects and/or a combination of dominance and epistasis. Furthermore, higher levels of inbreeding were associated with less socially desirable personality trait levels in three of the four personality dimensions. These findings are consistent with genetic variation in personality traits having been maintained by mutation–selection balance.

Effort-reward imbalance, heart rate, and heart rate variability: the Cardiovascular Risk in Young Finns Study.

Background: Work stress indicated by effort—reward imbalance is hypothesized to cause autonomic arousal, which, if prolonged or frequent, could contribute to cardiovascular pathology. However, only limited empirical evidence on this mechanism is available. Purpose: This study examined associations between effort-reward imbalance, heart rate (HR), and heart rate variability (HRV). Method: The participants were 457 women and 406 men (mean age 32.3 years) derived from the population-based Young Finns Study. Effort—reward imbalance was defined as the ratio between effort and reward, higher efforts compared to rewards indicating greater imbalance. Results: In age-adjusted regression models, higher effort-reward imbalance was associated with lower HRV, and lower reward was associated with higher HR among women. These associations were not attenuated after additional adjustments for demographic characteristics and coronary risk factors. No significant associations of effort—reward imbalance or its components with HR and HRV were found in men. Conclusion: Our finding of lower HRV and higher HR in young healthy women with high effort—reward imbalance and low rewards provides evidence of a potential mechanism that may link effort-reward imbalance to the development of coronary heart disease (CHD) in women.

MAINTENANCE OF GENETIC VARIATION IN HUMAN PERSONALITY: TESTING EVOLUTIONARY MODELS BY ESTIMATING HERITABILITY DUE TO COMMON CAUSAL VARIANTS AND INVESTIGATING THE EFFECT OF DISTANT INBREEDING

Personality traits are basic dimensions of behavioral variation, and twin, family, and adoption studies show that around 30% of the between‐individual variation is due to genetic variation. There is rapidly growing interest in understanding the evolutionary basis of this genetic variation. Several evolutionary mechanisms could explain how genetic variation is maintained in traits, and each of these makes predictions in terms of the relative contribution of rare and common genetic variants to personality variation, the magnitude of nonadditive genetic influences, and whether personality is affected by inbreeding. Using genome‐wide single nucleotide polymorphism (SNP) data from > 8000 individuals, we estimated that little variation in the Cloninger personality dimensions (7.2% on average) is due to the combined effect of common, additive genetic variants across the genome, suggesting that most heritable variation in personality is due to rare variant effects and/or a combination of dominance and epistasis. Furthermore, higher levels of inbreeding were associated with less socially desirable personality trait levels in three of the four personality dimensions. These findings are consistent with genetic variation in personality traits having been maintained by mutation–selection balance.

Childhood Environmental and Genetic Predictors of Adulthood Obesity: The Cardiovascular Risk in Young Finns Study

CONTEXT Obesity from childhood to adulthood is associated with adverse health later in life. Increased youth BMI is a risk factor for later obesity, but it is unknown whether identification of other risk factors, including recently discovered genetic markers, would help to identify children at risk of developing adult obesity. OBJECTIVES Our objective was to examine the childhood environmental and genetic predictors of adult obesity. DESIGN, SETTING, AND PARTICIPANTS We followed 2119 individuals of the Cardiovascular Risk in Young Finns Study for up to 27 yr since baseline (1980, age 3-18 yr). MAIN OUTCOME MEASURE We evaluated adult obesity [body mass index (BMI) ≥ 30 kg/m(2)]. RESULTS The independent predictors (P < 0.05) of adult obesity included childhood BMI, C-reactive protein (CRP), family income (inverse), mothers BMI, and polymorphisms near genes TFAP2B, LRRN6C, and FLJ35579. A risk assessment based on childhood BMI, mothers BMI, and family income was superior in predicting obesity compared with the approach using data only on BMI (C-statistics 0.751 vs. 0.772, P = 0.0015). Inclusion of data on childhood CRP and novel genetic variants for BMI did not incrementally improve C-value (0.779, P = 0.16). A nonlaboratory risk score (childhood BMI, mothers BMI, and family income) predicted adult obesity in all age groups between 3-18 yr (P always <0.001). CONCLUSIONS Childhood BMI, CRP, family income (inversely), mothers BMI, and polymorphisms near genes FLJ35779, TFAP2B, and LRRN6C are independently related to adulthood obesity. However, because genetic risk markers and CRP only marginally improve the prediction, our results indicate that children at high risk of adult obesity can be identified using a simple non-laboratory-based risk assessment.

Associations of personality profiles with various aspects of well-being: A population-based study

BACKGROUND Well-being consists of affective and non-affective components. Personality traits measure individual differences in adaptive functioning and mental health. In a previous Israeli study personality was strongly associated with well-being. However, it is not well known which aspects of this association are culture-specific, and which are common to most cultures. METHODS 1940 volunteer participants of the Cardiovascular Risk in Young Finns (CRYF) study completed the Temperament and Character Inventory (TCI), and the Multidimensional Scale of Perceived Social Support (PSS). Questions about positive and negative affect, satisfaction with life, and subjective health were also included. Multidimensional personality profiles were used to evaluate the linear and non-linear effects of interactions among dimensions on different aspects of well-being. RESULTS Self-directedness was strongly associated with all aspects of well-being regardless of interactions with other dimensions. Cooperativeness was also associated with several aspects of well-being but especially strongly with perceived social support. Self-transcendence was associated with both positive and negative affect when the influence of the other character dimensions was taken into account. Personality explained half the variance in non-affective well-being and two thirds of the variance in affective well-being. LIMITATIONS The same assessment instruments were not used in the two countries we compared. Our data were cross-sectional. CONCLUSIONS Self-directedness and Cooperativeness are positively associated with well-being regardless of culture. The effect of Self-transcendence, however, seems to be culture-specific. Self-transcendence increases positive affect but, based on culture, it can also increase negative affect.

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.