Covariation of psychosocial characteristics associated with cardiovascular disease: genetic and environmental influences

Distinct biological signature and modifiable risk factors underlie the comorbidity between major depressive disorder and cardiovascular disease

Major depressive disorder (MDD) and cardiovascular disease (CVD) are often comorbid, resulting in excess morbidity and mortality. Here we show that CVDs share most of their genetic risk factors with MDD. Multivariate genome-wide association analysis of shared genetic liability between MDD and atherosclerotic CVD revealed seven loci and distinct patterns of tissue and brain cell-type enrichments, suggesting the involvement of the thalamus. Part of the genetic overlap was explained by shared inflammatory, metabolic and psychosocial or lifestyle risk factors. Our data indicated causal effects of genetic liability to MDD on CVD risk, but not from most CVDs to MDD, and showed that the causal effects were partly explained by metabolic and psychosocial or lifestyle factors. The distinct signature of MDD-atherosclerotic CVD comorbidity suggests an immunometabolic subtype of MDD that is more strongly associated with CVD than overall MDD. In summary, we identified biological mechanisms underlying MDD-CVD comorbidity and modifiable risk factors for prevention of CVD in individuals with MDD.

Genetic and Environmental Influences on Perceived Social Support: Differences by Sex and Relationship

Previous research has shown that self-reports of the amount of social support are heritable. Using the Kessler perceived social support (KPSS) measure, we explored sex differences in the genetic and environmental contributions to individual differences. We did this separately for subscales that captured the perceived support from different members of the network (spouse, twin, children, parents, relatives, friends and confidant). Our sample comprised 7059 male, female and opposite-sex twin pairs aged 18−95 years from the Australian Twin Registry. We found tentative support for different genetic mechanisms in males and females for support from friends and the average KPSS score of all subscales, but otherwise, there are no sex differences. For each subscale alone, the additive genetic (A) and unique environment (E) effects were significant. By contrast, the covariation among the subscales was explained — in roughly equal parts — by A, E and the common environment, with effects of different support constellations plausibly accounting for the latter. A single genetic and common environment factor accounted for between half and three-quarters of the variance across the subscales in both males and females, suggesting little heterogeneity in the genetic and environmental etiology of the different support sources.

Physical Aggression and Coronary Artery Calcification: A North Texas Healthy Heart Study

BACKGROUND

The purpose of this study was to determine the association between aspects of hostility and coronary artery calcification (CAC) scores. Specifically, analyses differentiated between subtypes of hostility and their relation to CAC.

METHODS

A sample of 571 patients aged 45 or older with no history of cardiovascular disease completed assessments of demographic, psychosocial, and medical history, along with a radiological CAC determination. Logistic regression was used to determine the association between hostility and CAC. Hostility was measured using the Aggression Questionnaire, which measured total aggression and how aggression is manifested on four scales: Physical, Verbal, Anger, and Hostility Aggression.

RESULTS

Regression analyses indicated that only the physical aggression parameter was related to CAC: a 5% increase in odds of CAC presence was indicated for every point increase in physical aggression. The association remained significant in adjusted analyses. Other factors associated with CAC in adjusted analyses included: age, gender, race/ethnicity, BMI, and dyslipidemia.

CONCLUSIONS

Psychosocial factors, such as physical aggression, are emerging factors that need to be considered in cardiovascular risk stratification.

Toxic Affect: Are Anger, Anxiety, and Depression Independent Risk Factors for Cardiovascular Disease?

Three negative affective dispositions—anger, anxiety, and depression—are hypothesized to increase physical disease risk and have been the subject of epidemiological studies. However, the overlap among the major negative affective dispositions, and the superordinate construct of trait negative affectivity (NA) are only beginning to be tested. Presented here is a narrative review of recent prospective studies that simultaneously tested anger, anxiety, depression, and trait NA as risk factors for cardiac outcomes. Anxiety and depression emerged as independent risk factors for premature heart disease in population studies of persons nominally healthy at baseline, and for recurrence/mortality among patients with existing heart disease. General trait NA also was a cardiac risk factor in population samples.

Exploring the path between depression, anxiety and 10-year cardiovascular disease incidence, among apparently healthy Greek middle-aged adults: The ATTICA study

OBJECTIVES

Although there is substantial evidence that psychological factors play an important role in the onset and course of cardiovascular disease (CVD), less is known about their combined effect and the pathways by which they affect cardiovascular health. The present work aimed to prospectively explore the effects of depression and anxiety on the 10-year CVD incidence, in relation to other lifestyle determinants, as linking factors in the context of the ATTICA study. Study design/Main outcome measures: The ATTICA study is a population-based, health and nutrition prospective cohort study (2002-2012), during which 853 middle-aged participants without a history of CVD [453 men (aged 45±13years) and 400 women (aged 44±18years)], underwent psychological evaluations at enrollment. The latent trait of depression and anxiety combined measure was estimated and referred as "Psychological distress"; path analysis was applied to describe the relationships among the different factors.

RESULTS

"Psychological distress" was positively associated with the 10-year CVD incidence (adjusted OR per 10 units: 1.4, 95% CI: 1.1, 1.7). Three linking pathways were revealed: sedentariness, inflammation and metabolic syndrome. Moreover, "Psychological distress" mediated the association between socioeconomic status (SES) and CVD, with participants of low SES scoring higher on the psychological measure (adjusted linear regression coefficient b: -7.1, 95% CI: -9.7, -4.5).

CONCLUSIONS

Lifestyle and clinical factors seem to link psychological distress with CVD development. Joint psychological assessments should be considered for inclusion in CVD preventive strategies, which should incorporate interventions for interrupting the linking pathways.

The association between perceived social support and amygdala structure

The subjective perception of social support plays a crucial role in human well-being. However, its structural neural substrates remain unknown. We hypothesized that the amygdala, specifically its laterobasal and superficial subregions, which have been suggested to serve social functions, could be associated with the level of perceived social support. To test this hypothesis, we assessed perceived social support using the Multidimensional Scale of Perceived Social Support. In addition, we measured the volume and shape of the amygdala using structural magnetic resonance imaging in 49 healthy participants. Global amygdala volume in the left hemisphere was positively associated with the perceived social support score after adjusting for total cerebral volume, sex, age, intelligence, and five-factor personality domains. The local shape of the laterobasal and superficial subregions of the left amygdala showed the same association with perceived social support. These data suggest that the social subregions of the left amygdala are associated with the implementation of perceived social support.

OXTR polymorphism predicts social relationships through its effects on social temperament

Humans have a fundamental need for strong interpersonal bonds, yet individuals differ appreciably in their degree of social integration. That these differences are also substantially heritable has spurred interest in biological mechanisms underlying the quality and quantity of individuals' social relationships. We propose that polymorphic variation in the oxytocin receptor gene (OXTR) associates with complex social behaviors and social network composition through intermediate effects on negative affectivity and the psychological processing of socially relevant information. We tested a hypothesized social cascade from the molecular level (OXTR variation) to the social environment, through negative affectivity and inhibited sociality, in a sample of 1295 men and women of European American (N = 1081) and African American (N = 214) ancestry. Compared to European Americans having any T allele of rs1042778, individuals homozygous for the alternate G allele reported significantly lower levels of negative affectivity and inhibited sociality, which in turn predicted significantly higher levels of social support and a larger/more diverse social network. Moreover, the effect of rs1042778 variation on social support was fully accounted for by associated differences in negative affectivity and inhibited sociality. Results replicated in the African American sample. Findings suggest that OXTR variation modulates levels of social support via proximal impacts on individual temperament.

Depressive symptom clusters as predictors of 6-year increases in insulin resistance: data from the Pittsburgh Healthy Heart Project

OBJECTIVE

To examine longitudinal bidirectional associations between two depressive symptom clusters-the cognitive-affective and somatic-vegetative clusters--and insulin resistance, a marker of prediabetes.

METHODS

Participants were 269 adults aged 50 to 70 years without diabetes enrolled in the Pittsburgh Healthy Heart Project, a prospective cohort study. At baseline and 6-year visits, participants completed the Beck Depression Inventory-II (BDI-II) and underwent a blood draw to quantify fasting insulin and glucose. We examined baseline BDI-II total, cognitive-affective, and somatic-vegetative scores as predictors of 6-year change in the homeostatic model of assessment (HOMA) score, an estimate of insulin resistance computed from fasting insulin and glucose. We also examined baseline HOMA score as a predictor of 6-year change in BDI-II total and subscale scores.

RESULTS

Regression analyses, adjusted for demographic factors and baseline HOMA score, revealed that the baseline BDI-II somatic-vegetative score (β = 0.14, p = .025), but not the cognitive-affective (β = 0.001, p = .98) or total (β = 0.10, p = .11) scores, predicted 6-year HOMA change. This result persisted in models controlling for anxiety symptoms and hostility. Several factors were examined as candidate mediators; however, only change in body mass index was a significant mediator (p = .042), accounting for 23% of the observed association. Baseline HOMA score did not predict 6-year change in BDI-II total or subscale scores (all p values >.56).

CONCLUSIONS

Among adults aged 50 to 70 years, the somatic-vegetative symptoms of depression (e.g., fatigue, sleep disturbance, and appetite changes) may worsen insulin resistance and increase diabetes risk, partly, by increasing body mass index.

Cardiovascular disease, psychosocial factors, and genetics: the case of depression

Psychosocial factors are associated with cardiovascular disease, but little is known about the role of genetics in this relationship. Focusing on the well-studied phenotype of depression, current data show that there are shared genetic factors that may give rise to both depression and CVD, and these genetic risks appear to be modified by gender. This pleiotropic effect suggests that a single pathway, when perturbed, gives rise to the dual phenotypes of CVD and depression. The data also suggest that women contribute disproportionately to the depression-CVD comorbidity, and this unbalanced contribution is attributable, in part, to genetic factors. While the underlying biology behind this relationship is unclear, recent data support contributions from inflammatory or serotonergic pathways toward the comorbidity between CVD and depression. Even without knowledge of a specific mechanism, epidemiological observations offer new directions to explain the relationship between depression and CVD that have both research and clinical applications.

Cross-sectional changes in patterns of allostatic load among persons with varying disabilities, NHANES: 2001-2010

BACKGROUND

Allostatic Load (AL) is a measure of physiological stress that correlates with morbidity and mortality.

OBJECTIVE

The purpose of this study was to evaluate patterns of AL among persons with each of eight categories of disability versus persons with no disabilities over the 10-year Healthy People 2010 examination period.

METHODS

The study examined measures of AL from the 2001-2010 National Health and Nutrition Examination Survey (NHANES). The independent variable was Disability Status (hearing, vision, memory, physical-mental-emotional, walking up 10 steps, bending or kneeling, lifting or carrying, assistive devices, no disability). Eight laboratory and one social AL dependent variables included blood pressure, body mass index (BMI), HDL cholesterol, number of friends, and neutrophil percentages. Weighted statistical analyses included one-way ANCOVA with age as the covariate and chi-square tests.

RESULTS

Among respondents, 2.3% had hearing disabilities; 14.0% vision disabilities, 4.6% memory disabilities; 1.5% physical, mental, emotional disabilities; 1.3%, 5.9%, and 3.5% various mobility disabilities; and 5.3% used assistive devices. Persons with disabilities had significantly higher BMI, lower HDL cholesterol, higher C-reactive protein, and higher neutrophil levels than persons without disabilities. Systolic and diastolic blood pressures decreased during the decade, but BMI increased. A range of 36.2-61.0% of persons with non-hearing disabilities exceeded BMI obesity thresholds during 2009, and 13.8-29.9% had fewer than three friends during 2009.

CONCLUSIONS

These findings support previous research linking risks for secondary conditions/morbidity and allostatic load while demonstrating associations between disabilities and AL, especially for persons with mobility disabilities.

Do negative emotional factors have independent associations with excess adiposity?

OBJECTIVE

Taken in isolation, depression, anxiety, and hostility/anger have been shown to predict obesity. It is unknown whether these negative emotional factors are associated with adiposity, independently of each other. The objective of this review was to determine whether negative emotional factors have independent associations with adiposity.

METHODS

We searched for observational studies examining adiposity and two or more negative emotional factors. Studies which examined a negative emotional factor using analyses which controlled for other emotional factor(s) were selected for the review.

RESULTS

Three prospective and 11 cross-sectional studies met our inclusion/exclusion criteria. Of these investigations, 64% indicated that depression had positive associations with adiposity, independent of anxiety or hostility, and 56% indicated that anxiety had independent associations with adiposity. Only 33% of studies found independent associations for hostility and adiposity; however, far fewer studies were available.

CONCLUSION

Depression and anxiety have independent associations with excess adiposity when controlling for other emotional factors. Additional studies are needed to determine whether hostility/anger is independently associated with excess adiposity. These results have implications for the design of effective obesity prevention programs.

Nonadditive Genetic Effects on Hostility in South Korean Adolescent and Young Adult Twins

Hostility has been shown to be a vulnerability marker for various health problems. The present study examined genetic and environmental contributions to individual differences in hostility in South Korean adolescent and young adult twins. Seven hundred and nineteen same- and opposite-sex twin pairs aged from 13 to 23 years completed a hostility scale. The scalar sex-limitation model was applied to the data. The best fitting model indicated that 34% of the total variation of hostility was attributable to genetic factors operating in a nonadditive manner. The remaining 66% of the variance was associated with nonshared environmental influences and measurement error. These findings were largely consistent with results from previous twin studies of personality based on Caucasian twins, rendering support for the pervasive influence of genetic non-additivity on human personality traits and the generalization of the heritability of personality across human populations.

Latent constructs in psychosocial factors associated with cardiovascular disease: an examination by race and sex

This study examines race and sex differences in the latent structure of 10 psychosocial measures and the association of identified factors with self-reported history of coronary heart disease (CHD). Participants were 4,128 older adults from the Chicago Health and Aging Project. Exploratory factor analysis (EFA) with oblique geomin rotation was used to identify latent factors among the psychosocial measures. Multi-group comparisons of the EFA model were conducted using exploratory structural equation modeling to test for measurement invariance across race and sex subgroups. A factor-based scale score was created for invariant factor(s). Logistic regression was used to test the relationship between the factor score(s) and CHD adjusting for relevant confounders. Effect modification of the relationship by race-sex subgroup was tested. A two-factor model fit the data well (comparative fit index = 0.986; Tucker-Lewis index = 0.969; root mean square error of approximation = 0.039). Depressive symptoms, neuroticism, perceived stress, and low life satisfaction loaded on Factor I. Social engagement, spirituality, social networks, and extraversion loaded on Factor II. Only Factor I, re-named distress, showed measurement invariance across subgroups. Distress was associated with a 37% increased odds of self-reported CHD (odds ratio: 1.37; 95% confidence intervals: 1.25, 1.50; p-value < 0.0001). This effect did not differ by race or sex (interaction p-value = 0.43). This study identified two underlying latent constructs among a large range of psychosocial variables; only one, distress, was validly measured across race-sex subgroups. This construct was robustly related to prevalent CHD, highlighting the potential importance of latent constructs as predictors of cardiovascular disease.

Hostility now, depression later? Longitudinal associations among emotional risk factors for coronary artery disease

BACKGROUND/PURPOSE

Given that emotional risk factors for coronary artery disease (CAD) tend to cluster within individuals, surprisingly little is known about how these negative emotions might influence one another over time. We examined the longitudinal associations among measures of depressive symptoms and hostility/anger in a cohort of 296 healthy, older adults.

METHODS

Participants completed the Beck Depression Inventory-II (BDI-II), Cook-Medley Hostility (Ho) scale, and Anger-In and Anger-Out subscales of the State-Trait Anger Expression Inventory at baseline and 6-year follow-up. We conducted a series of path analyses to evaluate the directionality of the depression-hostility/anger relationship.

RESULTS

Baseline Ho scale was a predictor of 6-year increases in BDI-II (beta = 0.15, p = 0.004), Anger-In (beta = 0.14, p = 0.002), and Anger-Out (beta = 0.11, p = 0.01). In contrast, baseline BDI-II, Anger-In, and Anger-Out did not predict change in any of the emotional variables. Additional path analytic models revealed that the pattern of relationships was not altered after controlling for demographic, biomedical, and behavioral covariates; anxiety symptoms; social support; and subjective sleep quality.

CONCLUSIONS

The present results suggest that the cognitive aspects of hostility/anger may precede and independently predict future increases in depressive symptoms but not vice versa. Our findings lead us to speculate that (a) hostility may exert part of its cardiotoxic influence by acting to precipitate and/or maintain symptoms of depression and that (b) the potency of depression interventions designed to improve cardiovascular outcomes might be enhanced by incorporating treatments addressing hostility.

Lack of social support in the etiology and the prognosis of coronary heart disease: a systematic review and meta-analysis

OBJECTIVE

To conduct a systematic review and meta-analysis on the relevance of low social support for the development and course of coronary heart disease (CHD).

METHODS

Three electronic databases were searched (MEDLINE, PsycINFO/PSYNDEX, and Web of Science 2007/03). More than 1700 papers were screened in a first step. We included prospective studies assessing the impact of social support in either an initially healthy study population (etiologic studies) or in a study population with preexisting CHD (prognostic studies).

OUTCOMES

Myocardial infarction in etiologic studies; cardiovascular mortality and all-cause mortality in prognostic studies. Effects were reported as relative risk (RR) or hazard ratio (HR).

RESULTS

There is some evidence for an impact of low functional social support on the prevalence of CHD in etiologic studies (RR, range, 1.00-2.23). In contrast, there is no evidence of an impact of low structural social support on the prevalence of myocardial infarction in healthy populations (RR, range, 1.01-1.2). In prognostic studies, results consistently show that low functional support negatively affects cardiac and all-cause mortality (pooled RR, range, 1.59-1.71). These results were also confirmed in analyses adjusted for other risk factors for disease progression (pooled HR, 1.59). It remains unclear whether low structural social support increases mortality in patients with CHD (pooled RR, between 1.56; pooled HR, 1.12, NS).

CONCLUSIONS

Because the perception of social support seems important for CHD prognosis, monitoring of functional social support is indicated in patients with CHD, and interventions to increase the perception of positive social resources are warranted.

Is brachial artery flow-mediated dilation associated with negative affect?

BACKGROUND

Trait negative affect has been implicated as a risk marker for cardiovascular disease, but the mechanisms underlying this association are uncertain.

PURPOSE

Our aim was to examine associations between trait measures of anger, hostility, depression, and anxiety with endothelial dysfunction via brachial artery flow-mediated dilation (FMD), an early indicator of cardiovascular disease.

METHOD

FMD was examined in 332 healthy older adults. Measures included Beck Anxiety and Depression Inventories, Cook-Medley Hostility Scale, and Spielberger State-Trait Anger Expression Inventory (Anger In, Anger Out, and Trait Anger).

RESULTS

Mean age was 60.5 +/- 4.8 years; 83% of participants were Caucasian and 49% were female. FMD was greater in women compared to men (6.17% vs. 4.07%, p < 0.001). Women reported significantly greater Anxiety (p < 0.001), and men reported greater Hostility (p = 0.004). In separate multivariable linear regression models controlling for cardiovascular risk factors, plus current hormone therapy for women, smaller FMD was associated with higher Anger In for women (beta = -0.222, p = 0.04) and showed a trend with higher Hostility for men (beta = -0.082, p = 0.09).

CONCLUSION

Endothelial dysfunction, as indicated by less vasodilatation of the brachial artery, is positively associated with measures of hostility and anger suppression in healthy older adults. Thus, associations between negative affect and cardiovascular health may be apparent early in the disease process.

A prospective evaluation of the directionality of the depression-inflammation relationship

Cross-sectional studies have found that individuals with depressive disorders or symptoms have elevated levels of inflammatory markers predictive of coronary artery disease, including interleukin-6 (IL-6) and C-reactive protein (CRP). Due to the paucity of prospective studies, however, the directionality of the depression-inflammation relationship is unclear. We evaluated the longitudinal associations between depressive symptoms and both IL-6 and CRP among 263 healthy, older men and women enrolled in the Pittsburgh Healthy Heart Project, a 6-year prospective cohort study. During the baseline and follow-up visits, participants completed the Beck Depression Inventory-II (BDI-II) to assess depressive symptoms and underwent blood draws to quantify serum IL-6 and CRP. Path analyses revealed that baseline BDI-II (beta=0.18, p=0.01, DeltaR(2)=0.02) was a predictor of 6-year change in IL-6, even after adjustment for demographic, biomedical, and behavioral factors as well as other negative emotions. Of all the factors examined, only body-mass index was a stronger predictor of IL-6 change than depressive symptoms. In contrast to these results, baseline IL-6 did not predict 6-year change in BDI-II. Evidence of a weak bidirectional relationship between BDI-II and CRP was also observed; however, neither of these longitudinal associations was significant. The present findings indicate that depressive symptoms may precede and augment some inflammatory processes relevant to coronary artery disease among healthy, older adults. Therefore, our results imply that depression may lead to inflammation and that inflammation may be one of the mechanisms through which depression contributes to cardiovascular risk.

The relative contributions of hostility and depressive symptoms to the income gradient in hospital-based incidence of ischaemic heart disease: 12-Year follow-up findings from the GLOBE study

There is evidence to support the view that both hostility and depressive symptoms are psychological risk factors for ischaemic heart disease (IHD), additional to the effects of lifestyle and biomedical risk factors. Both are also more common in lower socioeconomic groups. Studies to find out how socioeconomic status (SES) gets under the skin have not yet determined the relative contributions of hostility and depression to the income gradient in IHD. This has been examined in a Dutch prospective population-based cohort study (GLOBE study), with participants aged 15-74 years (n=2374). Self-reported data at baseline (1991) and in 1997 provided detailed information on income and on psychological, lifestyle and biomedical factors, which were linked to hospital admissions due to incident IHD over a period of 12 years since baseline. Cox proportional hazard models were used to study the contributions of hostility and depressive symptoms to the association between income and time to incident IHD. The relative risk of incident IHD was highest in the lowest income group, with a hazard ratio of 2.71. Men on the lowest incomes reported more adverse lifestyles and biomedical factors, which contributed to their higher risk of incident IHD. An unhealthy psychological profile, particularly hostility, contributed to the income differences in incident IHD among women. The low number of IHD incidents in the women however, warrants additional research in larger samples.

Citalopram intervention for hostility: results of a randomized clinical trial

Hostility is associated with an increased risk for cardiovascular disease (CVD). Because central serotonin may modulate aggression, we might expect selective serotonin reuptake inhibitors (SSRIs) to be effective in reducing hostility. Such effects have never been examined in individuals scoring high on hostility who are otherwise free from major Axis I psychopathology according to criteria in the Diagnostic and Statistical Manual of Mental Disorders (4th ed., Text Revision; American Psychiatric Association, 2000). A total of 159 participants (ages 30?50 years, 50% female) scoring high on 2 measures of hostility and with no current major Axis I diagnosis were randomly assigned to 2 months of citalopram (40 mg, fixed-flexible dose) or placebo. Adherence was assessed by electronic measurement and by drug exposure assessment. Treated participants showed larger reductions in state anger (Condition x Time; p = .01), hostile affect (p = 02), and, among women only, physical and verbal aggression (p = .005) relative to placebo controls. Treatment was also associated with relative increases in perceived social support (p = .04). The findings have implications for understanding the central nervous system correlates of hostility, its associations with other psychosocial risk factors for CVD, and, potentially, the design of effective interventions.

Dimensions of social support and depression in patients at increased psychosocial risk recovering from myocardial infarction

BACKGROUND

There is considerable evidence that depression and low social support are associated with increased morbidity and mortality for patients with coronary heart disease (CHD). However, there is a lack of consensus regarding the measurement of social support and its relation to depression.

PURPOSE

The primary purpose of the present study was to identify key dimensions of existing social support and depression measures for patients with CHD using factor analysis.

METHOD

Seven hundred-five patients with a recent acute myocardial infarction and either depression, low social support, or both, completed measures of several types of social support and depression. Exploratory and confirmatory factor analysis were used to examine the underlying dimensions of the existing social support and depression measures, and to compare theoretically plausible models specifying the relation between the social support and depression factors.

RESULTS

Confirmatory factor analysis indicated that an approach in which smaller facets of depression are measured (somatic, cognitive/affective, anxious) and social support (perceived emotional support from intimate relationships; perceived tangible support from peripheral contacts; and the number of children, relatives, and friends in a patient's support network), may be the most optimal way to measure social support and depression in this population RMSEA = 0.05; CFI = 0.81; TLI = 0.88).

CONCLUSION

Efforts to identify patients at increased psychosocial risk may be improved by screening for these subcomponents of social support and depression.

A genetic epidemiologic study of social support in a Chinese sample

Accumulated evidence suggests that social support is influenced by genetic and environmental factors. However, there are little data that examine this issue from Asian samples. We reported results from a preliminary study that examined familial effects on social support in a Chinese adult twin sample. We administered a 10-item social support instrument that measures three dimensions of social support (i.e., objective support, subjective support, and utilization of support) developed for the Chinese population. Two hundred forty-two same-sex twin pairs, where both members of the pair completed the personal interview, were included in the final analysis. Structural equation modeling was used to estimate additive genetic (A), shared environmental (C), and nonshared environmental (E) effects on each dimension of social support. Familial factors (A+C) explained 56.63% [95% CI = 45.48-65.72%] and 42.42% [95% CI = 29.93-53.25%] of the total phenotypic variances of subjective support and utilization of support, respectively. For the objective support, genetic effects did not exist, but common environmental effect explained 37.56% [95% CI = 26.17-48.28%] of the total phenotypic variances. Neither gender nor age effects were seen on any dimension of social support. Except for objective support, genetic factors probably influence variation in subjective support and utilization of support. Shared environmental factors may influence all dimensions of social support.

Physical activity as a potential mechanism through which social support may reduce cardiovascular disease risk

Social support has been associated with a reduced risk of cardiovascular disease (CVD). It has been suggested that the protective effect of social support is mediated through the autonomic nervous system and/or unhealthy lifestyle behaviors, but data are sparse, especially in diverse populations. The purpose of this study was to evaluate possible pathways through which social support may reduce cardiovascular disease risk. Baseline data from The National Heart, Lung, and Blood Institute Family Intervention Trial for Heart Health were included in this analysis (N = 501, mean age 48 +/- 13 years, 66% female, 36% nonwhite). Social support was calculated using the Enhancing Recovery in Coronary Heart Disease Patients Social Support Instrument, a validated tool measuring emotional and instrumental support. Emotional support is defined as the belief that one is cared about (high = score > or = 18); instrumental social support is defined as help with services (high = score > or = 3). Demographics, physical activity, and diet were assessed by standardized questionnaires, and cardiovascular disease risk factors were measured systematically. Linear regression models were adjusted for age, race/ethnicity, sex, marital status, and education. Higher instrumental social support was positively associated with minutes of physical activity per week (P = .007). Higher emotional social support was positively associated with number of days of physical activity per week (P = .023), number of servings of wine per week (P = .007), and increased high-density lipoprotein cholesterol (P = .014). A mediational analysis was performed, and the relationship between emotional social support and high-density lipoprotein cholesterol was significantly attenuated by physical activity days per week and number of servings of wine per week. No significant associations were found for other potential mediators tested including body mass index, waist circumference, and intake of omega-3 fatty acids, beer, or liquor. In this ethnically diverse population, emotional social support was linked to higher high-density lipoprotein cholesterol levels through increased physical activity and wine intake, suggesting possible mechanisms through which social support may reduce cardiovascular disease risk.

Depressive symptoms moderate the influence of hostility on serum interleukin-6 and C-reactive protein

OBJECTIVE

Recent evidence suggests that depressive symptoms and hostility may act together, as interacting factors, to have an effect on the circulating levels of inflammatory markers relevant to coronary artery disease. Further research, however, is needed to clarify the nature of this interaction and to determine whether previous findings extend to older adults. In this report we examined the cross-sectional associations of depressive symptoms, hostility, and their interaction with circulating levels of two such inflammatory markers-interleukin-6 (IL-6) and C-reactive protein (CRP).

METHODS

A total of 316 healthy, older adults underwent a blood draw for the assessment of serum IL-6 and CRP and completed the Beck Depression Inventory-II and the Cook-Medley Hostility Scale. Regression analyses were performed to examine depressive symptoms, hostility, and their interaction as predictors of serum IL-6 and CRP.

RESULTS

After adjustment for demographic factors, cardiovascular risk factors, and health behaviors, we detected depressive symptoms x hostility interactions for serum IL-6 (DeltaR(2) = .027, p < .01) and CRP (DeltaR(2) = .015, p < .05). Simple slope analyses revealed that hostility was positively related to serum IL-6 only among individuals with higher depressive symptoms. The pattern of results was similar for serum CRP, although none of the simple slopes was significant.

CONCLUSIONS

Our findings suggest that depressive symptoms may moderate the hostility-inflammation relationship such that hostility may augment inflammatory processes relevant to coronary artery disease only in the presence of depressive symptoms. Our results also extend previous findings from younger adults to older adults from the general community.

Fetal Origins of Stress-Related Adult Disease

During the past decade, a considerable body of evidence has emerged showing that circumstances during the fetal period may have lifelong programming effects on different body functions with a considerable impact on disease susceptibility. The purpose of this article is to provide a synopsis of these findings and their role in explaining the development of stress-related adult disease. In the context of Per Björntorp memorial symposium, stress-related disease will be interpreted broadly, including cardiovascular disease and components of the metabolic syndrome, for which the evidence of fetal origins is most abundant. It has however become evident that early-life programming has a much broader potential effect on an individual's health. For example, perinatal variables, such as low birth weight, have been associated with increased prevalence of depressive symptoms. Mechanistic studies in animals and humans have shown that lifelong programming of the hypothalamic-pituitary-adrenal axis (HPAA) function by fetal life conditions is likely to be a key factor in mediating associations with these disorders, which frequently are characterized by HPAA overactivity. Preliminary observations suggest a similar important role for early-life programming of sympathoadrenal function. Reduced HPAA activity is characteristic of a number of stress-related disorders, including posttraumatic stress disorder; chronic pain; fatigue; and atypical, melancholic depression. It is therefore highly plausible that susceptibility to these disorders originates in a similar manner during early life, although direct evidence is to a great deal lacking. Important targets for future research include distinction between the effects of different pregnancy conditions, such as maternal malnutrition, preeclampsia, and maternal infection, which may have dissimilar late-life consequences. This will be a crucial step when the associations that are currently emerging will be translated into disease prevention.

Covariation of psychological attributes and incident coronary heart disease in U.S. Air Force veterans of the Vietnam war

OBJECTIVE

The purpose of the present investigation was to examine the prospective associations of hostility, anger, depression, and anxiety, alone and in combination, to incident coronary heart disease (CHD).

METHODS

Subjects were 2105 men who participated in the Air Force Health Study, a 20-year study designed to evaluate the effects of herbicide exposure on various health outcomes in Air Force veterans of Operation Ranch Hand. Psychological attributes were assessed in 1985 using scales constructed from the Minnesota Multiphasic Personality Inventory. Participants were followed for an average of 15 years for evidence of ischemic heart disease (International Classification of Diseases codes 410-414, 428.4, or 36). The relation between psychological attributes and CHD was examined with Cox proportional hazard models.

RESULTS

Adjusting for CHD risk factors, depression, anxiety, hostility, and trait anger were significant predictors of incident CHD. In addition, a factor analytically derived psychological risk factor composite score was the strongest predictor of CHD.

CONCLUSIONS

These results suggest that the covariation of hostility, anger, depression, and anxiety accounts for the increased risk of CHD associated with each individual factor. The results of this study challenge the conventional approach of examining these psychological attributes in isolation.

Genetic and environmental influences on type A behavior pattern: evidence from twins and their parents in the Netherlands Twin Register

OBJECTIVE

There is a dose-response positive relationship between type A behavior (TABP) and cardiovascular disease-related symptoms. Estimates of heritability for TABP from previous studies vary; this might be explained by limitations in the sizes and compositions of the samples.

METHODS

This study combines a large sample size, twin and parental, data from males and females, two generations of young adults and older adults, and the use of structural equation modeling (SEM) and full information maximum likelihood (FIML) estimation. To assess TABP, the Jenkins Activity Survey (JAS) was collected from MZ and DZ twins and their parents (n = 1670 twin families). Structural equation modeling is used to evaluate and estimate the effects of additive and nonadditive genetic effects, nonshared environmental effects, and competitive sibling interaction.

RESULTS

Forty-five percent of the variance in TABP was the result of genetic factors (28% were additive and 17% were nonadditive). The remaining 55% of the variance was explained by environmental factors not shared by the members of the same family. Competitive sibling interaction effects were not significant. There was no evidence of sex differences either in variances or means.

CONCLUSION

Understanding the sources of variance on TABP is important for therapy and prevention. According to the present results, the relevant environmental factors for the development of TABP are not shared by the members of the same family. The genetic portion of the variance is also worth considering for therapeutic purposes. Although the genetic code cannot be altered, its effects on behavior may be modifiable through the treatment of the biological mediators.

Genetic analysis of anger: genetic dominance or competitive sibling interaction

The knowledge of the causes and development of anger is still scarce. Previous studies on the sources of variance on Type A Behavior Pattern (TABP) related measures found variable heritability estimates ranging from 0.12 to 0.68, and large differences between MZ and DZ correlations. Some authors considered dominance genetic effects, competitive sibling interaction and sex differences as possible mechanisms to explain the results, but most studies lacked power. The present study uses a large sample of more than 2,500 families, with longitudinal data from MZ and DZ pairs as well as their parents, to disentangle the sources of variance on anger. Model Fitting results showed that the sources of variance differ across sexes. For males 23% of the variance is due to additive genetic effects, and 26% to dominance genetic effects. For females 34% of the variance is due to additive genetic effects, and no dominance effects are found. There was no consistent evidence to confirm the presence of competitive sibling interaction as an alternative explanation for the low correlations in DZ males. The focus of research on the prediction of coronary heart disease (CHD) risk through psychological characteristics has recently changed from the multidimensional TABP to its emotional component: Anger. Understanding the sources of individual differences on anger can help to clarify the mechanisms that link it with CHD and its possible implications for treatment and prevention.

Social support and coronary heart disease: epidemiologic evidence and implications for treatment

OBJECTIVE

The present paper reviews theories of social support and evidence for the role of social support in the development and progression of coronary heart disease (CHD).

METHODS

Articles for the primary review of social support as a risk factor were identified with MEDLINE (1966-2004) and PsychINFO (1872-2004). Reviews of bibliographies also were used to identify relevant articles.

RESULTS

In general, evidence suggests that low social support confers a risk of 1.5 to 2.0 in both healthy populations and in patients with established CHD. However, there is substantial variability in the manner in which social support is conceptualized and measured. In addition, few studies have simultaneously compared differing types of support.

CONCLUSIONS

Although low levels of support are associated with increased risk for CHD events, it is not clear what types of support are most associated with clinical outcomes in healthy persons and CHD patients. The development of a consensus in the conceptualization and measurement of social support is needed to examine which types of support are most likely to be associated with adverse CHD outcomes. There also is little evidence that improving low social support reduces CHD events.

The interrelationship of psychosocial risk factors for coronary artery disease in a working population: do we measure distinct or overlapping psychological concepts?

There is growing evidence that psychosocial factors contribute to the risk of coronary artery disease. Commonly used psychometric scales share several features leading to questions about whether they reflect distinguishable concepts. Study participants were 822 employees of the Augsburg Cohort Study (mean age 40 years, 89% men). The authors analyzed the interrelationship between the following psychosocial measures by applying Pearson correlations and factor analysis to the Hospital Anxiety and Depression Scale (HADS), Type D Personality (DS14), the Maastricht Vital Exhaustion Questionnaire (VE), Social Support (F-SozU), the SF12 Health Survey, and Effort-Reward Imbalance. Although the full correlation matrix revealed low to medium associations supporting the notion that the applied psychometric scales show some conceptual overlap, factor analyses resulted in 13 distinguishable and interpretable factors, considerably reflecting the original psychometric scales. This strengthens the assumption that the psychometric scales used constitute distinct psychological concepts, in particular, depressive symptomatology and negative affectivity versus vital exhaustion.

Anger, Anxiety, and Depression as Risk Factors for Cardiovascular Disease: The Problems and Implications of Overlapping Affective Dispositions

Several recent reviews have identified 3 affective dispositions--depression, anxiety, and anger-hostility--as putative risk factors for coronary heart disease. There are, however, mixed and negative results. Following a critical summary of epidemiological findings, the present article discusses the construct and measurement overlap among the 3 negative affects. Recognition of the overlap necessitates the development of more complex affect-disease models and has implications for the interpretation of prior studies, statistical analyses, prevention, and intervention in health psychology and behavioral medicine. The overlap among the 3 negative dispositions also leaves open the possibility that a general disposition toward negative affectivity may be more important for disease risk than any specific negative affect.

C-reactive protein is associated with psychological risk factors of cardiovascular disease in apparently healthy adults

OBJECTIVE

The current study examined the relation of anger, hostility, and severity of depressive symptoms, alone and in combination, to C-reactive protein (CRP) in healthy men and women.

METHODS

A high sensitivity enzyme linked immuno sorbent assay (ELISA) was used to evaluate CRP levels in a multiethnic sample of 127 healthy, nonsmoking men and women. Fasting blood samples were collected the same day the assessments were done of anger and hostility using the Buss-Perry Aggression Questionnaire (BPAQ) and depressive symptomatology using the Beck Depression Inventory (BDI). A psychological risk factor (PRF) score representing a composite summary indicator of BDI and BPAQ-anger and -hostility was generated using principal component analysis. Log-transformed CRP values were examined using univariate and multivariate analyses adjusting for control variables of age, gender, body mass index (BMI), alcohol use, exercise frequency, ratio of total to high-density lipoprotein cholesterol, and family history of premature coronary heart disease (CHD).

RESULTS

Log-normalized CRP was correlated with BDI (r = 0.21, p =.02) and BPAQ anger (r = 0.20, p =.02), but not with BPAQ hostility. After adjustment for control variables, BDI (beta = 0.05, p =.011), BPAQ anger (beta = 0.05, p =.007), and the PRF composite score (beta = 0.27, p =.005), but not BPAQ hostility (beta = 0.03, p =.11), were significantly associated with log-normalized CRP.

CONCLUSIONS

Greater anger and severity of depressive symptoms, separately and in combination with hostility, were significantly associated with elevations in CRP in apparently healthy men and women. These associations were independent of potential confounding factors.

Cynical hostility, depressive symptoms, and the expression of inflammatory risk markers for coronary heart disease

Although the prognostic significance of depression and hostility has been established, little is known about how they operate together to influence disease processes. This study explored the independent and interactive relationships between these constructs and the expression of inflammatory markers implicated in the pathogenesis of coronary heart disease. One hundred adults completed measures of cynical hostility and depressive symptoms, and had blood drawn to assess serum levels of interleukin-1 beta, interleukin-6, and tumor necrosis factor-alpha. Depression was directly related to inflammatory markers, but hostility was not. A significant interaction between hostility and depression emerged. Among participants scoring low in depressive symptoms, hostility was positively associated with interleukin-6 and tumor necrosis factor-alpha concentrations. Hostility's association with these inflammatory markers was much weaker among participants with moderate depressive symptoms, however, and virtually nil among participants with severe depressive symptoms. Neither depression nor hostility was associated with interleukin-1 beta concentrations. These findings highlight the importance of considering both the independent and interactive relationships among psychosocial characteristics involved in disease.

Allelic variation in the serotonin transporter gene-linked polymorphic region (5-HTTLPR) and cardiovascular reactivity in young adult male and female twins of European-American descent

OBJECTIVE

To examine the effect of length variation in the serotonin transporter gene-linked polymorphic region (5-HTTLPR) on individual differences in cardiovascular response to psychological challenge.

METHODS

Heart rate (HR) and systolic and diastolic blood pressure (SBP, DBP) responses to computerized versions of two psychological challenges, the Stroop Color-Word Interference Test and mental arithmetic, were measured among 131 monozygotic (MZ) and 60 dizygotic (DZ) male or female (same-sex) European-American twin pairs. Among the 382 participants, 140 were homozygous for the "long" allele (l/l) at 5-HTTLPR, 61 were homozygous for the "short" allele (s/s), and 181 participants had one long and one short allele (l/s). Association and sib-pair analyses were performed to characterize genetic associations.

RESULTS

In the full sample, 5-HTTLPR was associated with HR reactivity to psychological challenge, albeit in interaction with sex. Task-elicited HR responses of women homozygous for the short allele were significantly greater than among: a) men of the same genotype; and b) women having either one (l/s) or two (l/l) long alleles at 5-HTTLPR. SBP and DBP responsivity was unrelated to genotype. These results were corroborated on reanalysis in two genetically independent subsamples. Variability at 5-HTTLPR also predicted HR reactivity in sib-pair analyses among DZ twins.

CONCLUSIONS

These results suggest that the commonly observed sex difference in HR reactivity may be, in part, genetically mediated and perhaps occur only among individuals homozygous for the short allele at 5-HTTLPR.

Plasma interleukin-6 is associated with psychological coronary risk factors: moderation by use of multivitamin supplements

The current study examined the relation of plasma IL-6 to anger, hostility, and severity of depressive symptoms as a function of multivitamin supplement use in 96 healthy, nonsmoking men (aged 18-46). Plasma IL-6 was independently associated with anger, hostility, and severity of depressive symptoms, as well as with a composite factor score, but only among nonusers. Among users, these associations were not significant. Multivitamin use was associated with lower plasma IL-6 levels, but only among men with high composite factor scores. Statistical adjustments for age, body mass index, resting diastolic blood pressure, fasting total cholesterol, high-density lipoprotein cholesterol, alcohol use, exercise frequency, and educational level did not alter these results. These data suggest that plasma IL-6 is elevated among healthy men characterized by a propensity for anger, a hostile disposition, and greater severity of depressive symptoms and that multivitamin supplements could ameliorate plasma IL-6 levels among these men.

Joint effect of hostility and severity of depressive symptoms on plasma interleukin-6 concentration

OBJECTIVE

Although interleukin (IL)-6 plays a significant role in cardiovascular disease, little is known about its relation to psychological risk factors, such as hostility and severity of depressive symptoms. The current study examined the joint effects of severity of depressive symptoms and hostility on plasma IL-6 in a sample of 90 healthy, nonsmoking men.

METHODS

After an overnight fast, blood samples for plasma IL-6 and fasting lipids were collected on the same day that the Beck Depression Inventory (BDI) and the Cook-Medley hostility (Ho) scale were administered. Plasma IL-6 was determined using enzymatic-linked immunosorbent assay (ELISA).

RESULTS

Analyses of logarithmically normalized plasma IL-6 adjusting for age, body mass index (BMI), fasting total cholesterol, high density lipoprotein (HDL), and resting diastolic blood pressure (DBP) revealed a significant BDI by Ho interaction (p =.026). Post hoc decomposition revealed that Ho was correlated with log-normalized plasma IL-6 (r = 0.59, p =.025) but only among men with BDI scores of 10 and above. Alternatively, BDI was correlated with log-normalized plasma IL-6 (r = 0.61, p =.003) but only among men with Ho scores of 23 and higher. Comparisons among BDI/Ho groups indicated that men with high scores on both the BDI and the Ho exhibited the highest median levels of plasma IL-6.

CONCLUSION

Hostile men who exhibited above normal levels of depressive symptoms had higher plasma levels of IL-6 suggestive of a subpopulation at increased risk for future cardiac events.