Laura Pulkki-Råback

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.

Early Socioeconomic Position and Blood Pressure in Childhood and Adulthood: The Cardiovascular Risk in Young Finns Study

Studies have found an association between low socioeconomic position in childhood and high adult blood pressure. It is unclear whether this association is explained by a pathway directly linking disadvantage to elevated blood pressure in childhood and adolescence, which then tracks into adulthood. We assessed parental socioeconomic position and systolic blood pressure in 1807 children and adolescents ages 3 to 18 years at baseline. Adult systolic blood pressure was measured 21 years later at ages 24 to 39 years. There was strong tracking of blood pressure from childhood to adulthood. Lower parental socioeconomic position was associated with higher blood pressure in childhood, adolescence (P<0.01), and adulthood (P<0.0001), with the mean age- and sex-adjusted systolic pressure differences between the highest and lowest socioeconomic groups varying between 2.9 and 4.3 mm Hg. With adjustment for blood pressure in childhood and adolescence, the regression coefficient between parental socioeconomic position and adult blood pressure attenuated by 32%. A similar level of attenuation (28%) occurred with adjustment for adult body mass index (BMI). With adjustment for both preadult blood pressure and adult BMI, the association between parental socioeconomic position and adult blood pressure was attenuated by 45%. Other factors, including birth weight and BMI in childhood and adolescence, had little impact on the association between parental socioeconomic position and adult blood pressure. These data suggest that early socioeconomic disadvantage influences later blood pressure in part through an effect on blood pressure in early life, which tracks into adulthood, and in part through an effect on BMI.

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.

Temperament in childhood predicts body mass in adulthood: The Cardiovascular Risk in Young Finns Study

This study examined associations of temperament at ages 6 to 12 with body-mass index (BMI) and waist circumference (WC) at ages 24 to 30 years. The participants were 619 men and women derived from the population-based Cardiovascular Risk in Young Finns Study. Temperament was operationalized as (negative) emotionality, sociability, and activity. High emotionality predicted increased BMI, independently of WC, and independently of childhood and adulthood risk factors for adult obesity. None of the temperament dimensions had any associations with WC after controlling for BMI. The findings suggest that temperamental difficulty in childhood may be a useful risk indicator for general body mass in adulthood, and the mechanisms relating temperament with body mass should be further explored.

Socioeconomic position in childhood and adult cardiovascular risk factors, vascular structure, and function: cardiovascular risk in young Finns study

Objective: To examine the association of childhood socioeconomic position (SEP) with adult cardiovascular risk factors, vascular structure, and vascular function in a contemporary population of young adults. Design: Population based prospective cohort study with baseline assessment in 1980. Setting: Finland. Participants: 856 men and 1066 women whose childhood SEP was determined by parental occupational status (manual, lower non-manual, upper non-manual) at age 3–18 years. Main outcome measures: Cardiovascular risk factors, carotid artery intima–media thickness, and brachial artery flow mediated vasodilatation, assessed at age 24–39 years. Results: After adjustment for age and adult SEP, systolic pressure was 2.3 mm Hg higher (p  =  0.0002), high density lipoprotein (HDL) cholesterol 0.03 mmol/l lower (p  =  0.02), and insulin resistance score (homeostasis model assessment index) 0.12 units greater (p  =  0.05) among men; and systolic pressure was 1.3 mm Hg higher (p  =  0.02), diastolic pressure 1.1 mm Hg higher (p  =  0.01), and height 1.1 cm lower (p < 0.0001) among women for each step down the childhood SEP hierarchy. Lower childhood SEP was associated with a 20% increase in the odds of having a waist circumference > 102 cm in men and > 88 cm in women (overall p  =  0.05). Childhood SEP was not associated with intima–media thickness, flow mediated vasodilatation, the metabolic syndrome, low density lipoprotein cholesterol, triglycerides, body mass index, alcohol consumption, or smoking. Conclusions: Among adults under 40, low childhood SEP predicted higher blood pressure and central obesity and, among men, unfavourable HDL cholesterol and insulin resistance, independent of current SEP. No independent effects were found on adult vascular structure, vascular function, or health related behaviours at this life stage.

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.

Depressive symptoms and C-reactive protein: The Cardiovascular Risk in Young Finns Study

BACKGROUND We tested the hypothesis that depressive symptoms in healthy young adults would be associated with elevated levels of C-reactive proteins (CRP). METHOD We studied the association between depressive symptoms and CRP in 1201 young adults, as a part of the on-going population-based Cardiovascular Risk in Young Finns Study. Depressive symptoms were determined by responses to a revised version of Becks Depression Inventory in 1992 and 2001. CRP and other known cardiac risk factors were measured in 2001. RESULTS Higher depressive symptomatology in 1992 and in 2001 and their means score were related to higher CRP levels (Bs range from 0.24 to 0.21, p < 0.001). These relationships persisted after separate adjustments for various risk factors including sex, age, education, oral contraceptive use, dietary fat, physical activity, alcohol consumption, smoking status, LDL-cholesterol, HDL-cholesterol, systolic blood pressure and history of acute infectious disease. Adjustments for obesity and triglycerides levels, however, somewhat attenuated the relationship between depressive symptoms and CRP. CONCLUSIONS We concluded that higher levels of depressive symptoms are associated with higher levels of CRP, but this association may largely be attributable to obesity or triglycerides.

Depressive symptoms and the metabolic syndrome in childhood and adulthood: a prospective cohort study.

OBJECTIVE To examine the reciprocal associations between depressive symptoms and clinical definitions of the metabolic syndrome in childhood and adulthood. DESIGN Population-based prospective cohort study of 921 participants (538 women and 383 men) in Finland. The components of the metabolic syndrome were measured in childhood (mean age 12 years) and again in adulthood (mean age 33 years). A revised version of the Beck Depression Inventory was used to assess depressive symptoms at the mean ages of 24 and 33. MAIN OUTCOME MEASURES Metabolic syndrome defined by the National Cholesterol Education Program Adult Treatment Panel III (NCEP), the European Group for the Study of Insulin Resistance, and the International Diabetes Federation criteria. RESULTS In women, depressive symptoms were associated with increased risk of the metabolic syndrome in adulthood (odds ratio for NCEP metabolic syndrome per 1 SD increase in depressive symptoms 1.40, 95% confidence interval 1.05-1.85). The metabolic syndrome in childhood, in turn, predicted higher levels of depressive symptoms in adulthood (p = .03). In men, no associations were found between depressive symptoms and the clinical definitions of the metabolic syndrome. CONCLUSION The process linking depressive symptoms with the metabolic syndrome may go into both directions and may begin early in life.

Genetic Variants in the Drd2 Gene Moderate the Relationship Between Stressful Life Events and Depressive Symptoms in Adults: Cardiovascular Risk in Young Finns Study

Objective: To examine the potential moderating role of DRD2 polymorphism (rs1800497) in the association between stressful life events and depressive symptoms among young adults. Although stressful life events, such as divorce, unemployment, and serious illness in the family, are generally associated with negative health outcomes, including depressive symptoms, there are large individual differences in coping with such events. A number of studies suggest that variants in dopamine receptor genes, such as DRD2, are associated with depression but it is unclear if such variants also modify the association between life events and depression. Methods: We analyzed the prospective data on life events and depressive symptoms in 1992 and 2001 related to 1611 young adults (672 men and 939 women, aged 15–30 years at baseline) who participated in the ongoing population-based cardiovascular risk in young Finns study. Results: Occurrence of stressful life events was associated with increased risk of subsequent depressive symptoms in men and women. However, this association was seen only among those who carried A2/A2 (n = 872) genotype. No such association was detected in participants carrying A1/A1 or A1/A2 (n = 486) genotype. Conclusion: DRD2 polymorphism moderates the effect of stressful life events on depressive symptoms and those who carry A2/A2 DRD2 genotypes may be more vulnerable than others. BMI = body mass index; CHD = coronary heart disease; CRYF = cardiovascular risk in young Finns; CVD = cardiovascular disease; HDL = high-density lipoprotein; LDL = low-density lipoprotein.

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.