Depression and cardiovascular disease: the end of simple models

Predictors of Psychological Distress among Post-Operative Cardiac Patients: A Narrative Review

Following surgery, over 50% of cardiac surgery patients report anxiety, stress and/or depression, with at least 10% meeting clinical diagnoses, which can persist for more than a year. Psychological distress predicts post-surgery health outcomes for cardiac patients. Therefore, post-operative distress represents a critical recovery challenge affecting both physical and psychological health. Despite some research identifying key personal, social, and health service correlates of patient distress, a review or synthesis of this evidence remains unavailable. Understanding these factors can facilitate the identification of high-risk patients, develop tailored support resources and interventions to support optimum recovery. This narrative review synthesises evidence from 39 studies that investigate personal, social, and health service predictors of post-surgery psychological distress among cardiac patients. The following factors predicted lower post-operative distress: participation in pre-operative education, cardiac rehabilitation, having a partner, happier marriages, increased physical activity, and greater social interaction. Conversely, increased pain and functional impairment predicted greater distress. The role of age, and sex in predicting distress is inconclusive. Understanding several factors is limited by the inability to carry out experimental manipulations for ethical reasons (e.g., pain). Future research would profit from addressing key methodological limitations and exploring the role of self-efficacy, pre-operative distress, and pre-operative physical activity. It is recommended that cardiac patients be educated pre-surgery and attend cardiac rehabilitation to decrease distress.

Depressive symptoms occurring after stroke by age, sex and socioeconomic status in six population-based studies: Longitudinal analyses and meta-analyses

AIMS

Population-based cohort studies that examined the effects of stroke on depressive symptoms in elderly participants with and without stroke in different countries/regions had yielded scant evidence. The objectives of this multi-cohort study were to identify the relationships between stroke and depressive symptoms and to assess the pooled risks of depressive symptoms in total populations and in stratified samples by age, sex, education levels, and total household income in large-scale studies.

METHODS

The associations in the overall participants in the six cohorts were examined using univariate and multivariable Cox proportional hazards models. The relationships in the population subgroups of the cohorts were determined using multivariable Cox regression models. Crude hazard ratios (HRs) were estimated, and adjusted or time-varying HRs were calculated and then pooled by meta-analyses.

RESULTS

During a median follow-up time of 3.8 (interquartile range [IQR]: 2.2-4.5) -7.9 (IQR: 4.0-8.0) years, 18267 participants out of 62150 participants developed incident cases of depressive symptoms. In the univariate Cox regression analyses, stroke was consistently linked to depressive symptoms across all studies, with HRs ranging from 1.39 (95% confidence interval [CI]: 1.04-1.85) to 1.84 (95% CI: 1.38-2.46). Adjusted HRs varied between 1.19 (95% CI: 0.89-1.59) and 1.48 (95% CI: 1.00-1.98), and time-varying HRs remained largely unchanged. According to the meta-analysis of overall HRs, stroke survivors were more likely than non-survivors to develop depressive symptoms (pooled HR: 1.35 (95% CI: 1.26-1.44)).

CONCLUSIONS

In general, stroke significantly increased the risk of depressive symptoms in total and stratified participants in most cohorts. In the future, extensive research will be needed to assess the variations in associations between various population subgroups.

Association between statins and the risk of suicide attempt, depression, anxiety, and seizure: A population-based, self-controlled case series study

BACKGROUND

Risk of suicide attempt, depression, anxiety and seizure and the association with statins is an ongoing debate. We aim to investigate the association between statins and the above neuropsychological outcomes, in specific pre- and post-exposure time windows.

METHODS

We identified patients aged 40-75 years old who were dispensed a statin between January 1, 2003 and December 31, 2012 from the Hong Kong Clinical Data Analysis & Reporting System (CDARS), an electronic medical records database. Patients with new onset of suicide attempt, depression, anxiety and seizure were derived from the original dataset separately, in a self-controlled case series study design. A non-parametric spline-based self-controlled case series model was built to measure continuous changes of risk.

RESULTS

We identified 396,614 statin users. The risk of each outcome was elevated prior to statin initiation with incidence rate ratios of 1.38 (95 % CI, 1.09-1.74) for suicide attempt, 1.29 (95 % CI, 1.15-1.45) for depression, 1.35 (95 % CI, 1.19-1.53) for anxiety, and 1.45 (95 % CI, 1.21-1.73) for seizure. The incidence rate ratios remained elevated after the initiation of statins during the first 90 and 91-365 days after statin prescription and decreased to the baseline level after 1 year of continuous prescription.

LIMITATIONS

CDARS includes prescription data but not adherence data, which could lead to misclassification of exposure periods.

CONCLUSIONS

Our study does not support a direct association between statin use and suicide attempt, depression, anxiety and seizure, whose risks could be explained by cardiovascular events, for which statins were prescribed.

Is retinal vein occlusion associated with depression symptoms?: A nationwide cohort study

Retinal vessels share similar anatomical and physiological characteristics with the cerebral microvasculature, and abnormal cerebral blood flow is reportedly associated with depressive disorder. However, there is limited evidence regarding the relationship between depression and the risk of retinal vein occlusion (RVO). This study aimed to investigate the association between depression and the prospective risk of RVO using nationally representative longitudinal data. This retrospective, nationwide, population-based cohort study included 9,178,222 people aged 20 years or older who underwent the Korean National Health Screening Program examination in 2009. The depression group consisted of subjects whose initial diagnoses were made between 2009 and 2010 (n = 128,700). The predictive value for RVO was analyzed using multivariate Cox proportional hazard regression models.From the Kaplan-Meier curves, the depression group showed significantly higher RVO incidence probability, relative to the comparison group (P < .0001). After all confounding variables were adjusted, the hazard ratio of RVO in the depression group with or without recurrence was 1.2 (95% confidence interval [CI]: 1.076-1.338) and 1.087 (95% CI: 1.012-1.167), respectively, relative to the comparison group. This is the first nationwide, population-based, epidemiologic study that evaluated the association between depression and the risk of RVO development. The presence of depression was significantly associated with increased risks of RVO, and the recurrence of depression showed a higher RVO incidence probability.

The familial and genetic contribution to the association between depression and cardiovascular disease: a twin cohort study

Depression and cardiovascular disease (ischemic heart disease and stroke) are associated in a bidirectional manner. Their relatively high heritability has led to the hypothesis that this co-occurrence is related to shared familial and genetic factors; this study aims to test this hypothesis. We included 23,498 monozygotic and 39,540 same-sex dizygotic twins from the Danish Twin Registry followed from January 1977 until December 2011 in nationwide Danish registries. We used survival analyses accounting for censoring and competing risk of death to estimate cumulative incidence, casewise concordance, relative recurrence risk, and heritability of the co-occurrence of depression and cardiovascular disease by age using monozygotic and same-sex dizygotic twin pairs. The casewise concordance of ischemic heart disease or stroke in twins whose co-twin was diagnosed with depression was at all ages similar for the monozygotic and dizygotic twin pairs and to the cumulative incidence of ischemic heart disease or stroke, respectively, in the entire twin population. A similar pattern was seen in analyses of depression risk given the co-twin being diagnosed with ischemic heart disease or stroke. Relative recurrence risk and heritability estimates were also of modest size and with confidence intervals including unity. Results were similar after stratification by gender as well as when redefining depression to include the use of antidepressant medication from 1995. Our findings do not support that co-occurrence between depression and cardiovascular disease is explainable by shared genetic factors, nor did we find strong evidence of a familial effect.

Combined influence of depression severity and low-grade inflammation on incident hospitalization and mortality risk in Italian adults

BACKGROUND

Depression and low-grade systemic inflammation are associated risk factors for hospitalizations and mortality, although the nature of this relationship is under-investigated.

METHODS

We performed multivariable Cox regressions of first hospitalization/mortality for all and specific causes vs depression severity, in an Italian population cohort (N=13,176; age≥35 years; 49.4% men), incrementally adjusting for sociodemographic, health and lifestyle factors. We tested potential mediation, additive and interactive effects of INFLA-score, a composite circulating inflammation index, and potential concurrent mediations of main lifestyles and chronic conditions.

RESULTS

Over 4,856 hospitalizations (median follow-up 7.28 years), we observed an increased incident risk of events by 24% (CI=17-32%) and 59% (30-90%) for moderate and severe depression, which also showed a 125% (33-281%) increased risk of all-cause mortality (over 471 deaths, 8.24 years). These remained stable after adjustment for lifestyles, health conditions and INFLA-score, which explained 2.1%, 7.6%, 16.3% and 8%, 14.9% and 12% of depression influence on hospitalizations and mortality risk, respectively. These proportions remained substantially stable after reciprocal adjustments. INFLA-score showed significant additive (but not interactive) effects on both hospitalizations and mortality risk.

LIMITATIONS

Depression severity was defined using a sub-version of Patient Health Questionnaire 9, which was validated here. Directionality links among exposures could not be established since they were collected simultaneously.

CONCLUSIONS

These findings suggest a combined influence of depression and low-grade inflammation on health, which is partly intertwined and dependent on lifestyles and chronic conditions. This suggests the existence of pathways other than inflammation through which depression may play its detrimental effect.

Association of Recognized and Unrecognized Myocardial Infarction With Depressive and Anxiety Disorders in 125,988 Individuals: A Report of the Lifelines Cohort Study

OBJECTIVE

No previous study has focused on recognition of myocardial infarction (MI) and the presence of both depressive and anxiety disorders in a large population-based sample. The aim of this study was to investigate the association of recognized MI (RMI) and unrecognized MI (UMI) with depressive and anxiety disorders.

METHODS

Analyses included 125,988 individuals enrolled in the Lifelines study. Current mental disorders according to the Diagnostic and Statistical Manual of Mental Disorders (Fourth Edition) were assessed with the Mini-International Neuropsychiatric Interview. UMI was detected using electrocardiogram in participants who did not report a history of MI. The classification of RMI was based on self-reported MI history together with the use of either antithrombotic medications or electrocardiogram signs of MI. Analyses were adjusted for age, sex, smoking, somatic comorbidities, and physical health-related quality of life as measured by the RAND 36-Item Health Survey in different models.

RESULTS

Participants with RMI had significantly higher odds of having any depressive and any anxiety disorder as compared with participants without MI (depressive disorder: odds ratio [OR] = 1.86, 95% confidence interval [CI] = 1.38-2.52; anxiety disorder: OR = 1.60, 95% CI = 1.32-1.94) after adjustment for age and sex. Participants with UMI did not differ from participants without MI (depressive disorder: OR = 1.60, 95% CI = 0.96-2.64; anxiety disorder: OR = 0.73, 95% CI = 0.48-1.11). After additional adjustment for somatic comorbidities and low physical health-related quality of life, the association between RMI with any depressive disorder was no longer statistically significant (OR = 1.18; 95% CI =0.84-1.65), but the association with any anxiety disorder remained (OR = 1.27, 95% CI = 1.03-1.57).

CONCLUSIONS

Recognition of MI seems to play a major role in the occurrence of anxiety, but not depressive, disorders.

An attempt to explain the bidirectional association between ischaemic heart disease, stroke and depression: a cohort and meta-analytic approach

BACKGROUND

Depression and cardiovascular diseases (CVDs) are common diseases and associated in a bidirectional manner.

AIMS

To examine whether a bidirectional association between CVD and depression could be explained by shared risk factors, misclassification of disease measures or non-response.

METHOD

A total of 10 population-based cohorts including 93 076 men and women (mean age 54.4 years, s.d. = 9.2) and an additional 10 510 men (mean age 51.2 years, s.d. = 0.3) were followed for subsequent depression, ischaemic heart disease (IHD) and stroke in the Danish National Patient Registry from health examinations between 1982 and 2015 and until end of follow-up in 2017-2018. Exposures were physicians' diagnoses of IHD, stroke, depression or self-reported chest pain, depression, use of antidepressant medication and the Major Depression Inventory at the time of study entry in the Metropolit study. Associations were analysed using Cox proportional hazard regression with disease as time-dependent variables.

RESULTS

IHD and stroke were associated with subsequent depression (hazard ratio (HR) for IHD: 1.79, 95% CI 1.43-2.23 and HR for stroke: 2.62, 95% CI 2.09-3.29) and the associations were present in both men and women. Adjustment for the shared risk factors socioeconomic status, lifestyle, body mass index, statin use and serum lipids did not change the risk estimates. Furthermore, depression was associated with higher risk of subsequent IHD (HR = 1.63, 95% CI 1.36-1.95) and stroke (HR = 1.94, 95% CI 1.63-2.30). The associations were also present when the analyses were based on self-reported disease measures or restricted to include non-responders.

CONCLUSIONS

The bidirectional association between CVD and depression was not explained by shared risk factors, misclassification or non-response.

The impact of mental vulnerability on the relationship between cardiovascular disease and depression

Background.

The mechanisms linking cardiovascular disease (CVD) and depression are still not established. We investigated the impact of mental vulnerability on the relationship between CVD and depression.

Methods.

A total of 19,856 individuals from five cohorts of random samples of the background population in Copenhagen were followed from baseline (1983–2011) until 2017 in Danish registries. Additive hazard and Cox proportional hazard models were used to analyze the effects of confounding by mental vulnerability as well as interactions between mental vulnerability and CVD on the risk of depression.

Results.

During follow-up, 15.3% developed CVD, while 18.1% experienced depression. A strong positive association between CVD and depression (hazard ratio: 3.60 [95% confidence intervals (CI): 3.30; 3.92]) corresponding to 35.4 (95% CI: 31.7; 39.1) additional cases per 1,000 person-years was only slightly attenuated after adjustment for mental vulnerability in addition to other confounders. Synergistic interaction between CVD and mental vulnerability was identified in the additive hazard model. Due to interaction between CVD and mental vulnerability, CVD was associated with 50.9 more cases of depression per 1,000 person-years among individuals with high mental vulnerability compared with individuals with low mental vulnerability.

Conclusions.

Mental vulnerability did not explain the strong relationship between CVD and depression. CVD was associated with additional cases of depression among individuals with higher mental vulnerability indicating that this group holds the greatest potential for intervention, for example, in rehabilitation settings.

Depressive symptoms prior to and after incident cardiovascular disease and long-term survival. A population-based study of older persons

BACKGROUND

Depression after a cardiovascular disease event (post-CVD) is associated with increased mortality. However, little is known about how pre-existing depression affects survival after CVD incidence.

AIM

To evaluate whether depressive symptoms preceding first incident CVD (pre-CVD) affects survival.

METHODS

From the Rotterdam Study, 6,932 persons aged 55+ and free of dementia and CVD completed the Center for Epidemiological Studies Depression (CES-D) scale every 4 to 5 years from 1993. CES-D subdomains were positive affect, negative affect, somatic symptoms, and interpersonal affect. Persons were followed for mortality and CVD.

RESULTS

During 15-year follow-up, 22% of participants suffered their first incident CVD. Pre-CVD depressive symptoms was not associated with mortality after adjustment for smoking status and physical function (HR per 10-point score: 1.05, 95%CI: 0.99-1.10). After first incident CVD, depressive symptoms increased. Higher post-CVD depressive symptoms was associated with increased mortality (HR: 1.13, 95%CI: 1.06, 1.22). The relation between post-CVD depressive symptoms and mortality was no longer statistically significant after adjustment for pre-CVD depressive symptoms. Pre-CVD and post-CVD measures of somatic symptoms and positive affect were associated with mortality.

CONCLUSIONS

During 15 years follow-up in community-dwelling older adults, the relation between higher depressive symptoms measured before first incident CVD and mortality was not independent of health status. Whereas, higher depressive symptoms measured after CVD was associated with increased mortality, was not independent of pre-CVD depressive symptoms. Given the associations observed between positive affect and mortality, positive affect may be the reason we observed a relation between depressive symptoms and mortality.

Depression with inflammation: longitudinal analysis of a proposed depressive subtype in community dwelling older adults

OBJECTIVE

It has been proposed that inflammation may be causally related to depression. If this is the case, it may be possible to distinguish an inflammatory depressive subtype according to illness course, pattern of co-morbidity and symptom profile.

METHODS

Eight hundred and eleven community dwelling older adults with depression (8 item Center for Epidemiologic Studies scale ≥ 4) from the English Longitudinal study of Ageing (ELSA) were followed for a median of 47 months. Participants with depression and inflammation (C Reactive Protein > 3 mg/l) were compared to those with depression alone.

RESULTS

In a longitudinal analysis, depression with associated inflammation was more likely to persist over time. This association was independent of baseline depression severity and medical co-morbidity (OR 1.47 95% CI 1.03 - 2.10, p = 0.034) but was no longer significant following further adjustment for body mass index (OR 1.37 95% CI 0.94 - 2.01, p = 0.106). Inflammation either partially or completely mediated the association between medical co-morbidity, body mass index and depression at follow-up. Depression with inflammation was associated with more amotivation, less sadness, greater medical co-morbidity and higher body mass index.

CONCLUSIONS

Our findings provide some support for an inflammatory contribution to depression. This subgroup has a worse prognosis and may benefit from interventions targeting co-morbidity, body mass index and associated inflammation. Copyright © 2016 John Wiley & Sons, Ltd.

Fear and distress disorders as predictors of heart disease: A temporal perspective

OBJECTIVE

Few studies have been able to contrast associations of anxiety and depression with heart disease. These disorders can be grouped in fear and distress disorders. Aim of this study was to study the association between fear and distress disorders with subsequent heart disease, taking into account the temporal order of disorders.

METHODS

Twenty household surveys were conducted in 18 countries (n=53791; person years=2,212,430). The Composite International Diagnostic Interview assessed lifetime prevalence and age at onset of disorders, and respondents were categorized into categories based on the presence and timing of fear and distress disorders. Heart disease was indicated by self-report of physician-diagnosed heart disease or self-report of heart attack, together with year of onset. Survival analyses estimated associations between disorder categories and heart disease.

RESULTS

Most respondents with fear or distress disorders had either pure distress or pure fear (8.5% and 7.7% of total sample), while fear preceded distress in the large majority of respondents with comorbid fear and distress (3.8% of total sample). Compared to the "no fear or distress disorder" category, respondents with pure fear disorder had the highest odds of subsequent heart disease (OR:1.8; 95%CI:1.5-2.2; p<0.001) and compared to respondents with pure distress disorder, these respondents were at a significantly increased risk of heart disease (OR:1.3; 95%CI:1.0-1.6; p=0.020).

CONCLUSION

This novel analytic approach indicates that the risk of subsequent self-reported heart disease associated with pure fear disorder is significantly larger than the risk associated with distress disorder. These results should be confirmed in prospective studies using objective measures of heart disease.

Trajectories of Physical Activity Predict the Onset of Depressive Symptoms but Not Their Progression: A Prospective Cohort Study

This prospective, community-based study examined trajectories of physical activity from childhood to adulthood and whether these trajectories contributed to depressive symptoms in adulthood to a greater degree than adulthood physical activity. Participants (n = 3596) were from the ongoing Cardiovascular Risk in Young Finns Study which started in 1980. Depressive symptoms were measured with Beck Depression Inventory (BDI-II) in 2012, and physical activity was assessed from 1980 to 2011 with self-reports. Analyses were adjusted for age, sex, childhood negative emotionality, socioeconomic factors, previous depressive symptoms, social support, body mass index, and smoking status (1980-2007). Highly, moderately, and lightly physically active trajectory groups were identified. Highly active participants reported lower levels of depressive symptoms compared to lightly active ones (p < 0.001) and compared to moderately active ones (p = 0.001). Moderately active participants had less symptoms than lightly active ones (p < 0.001). High levels of adulthood physical activity associated with lower levels of depressive symptoms (p < 0.001). The findings did not withstand adjustment for previous depressive symptoms (p > 0.05). Lifelong physical activity trajectories or adulthood physical activity was not associated with the progression of depressive symptoms in adulthood. Thus, physical activity history does not contribute to the progression of the depressive symptoms to a greater degree than adulthood physical activity.

Base Rates of Depressive Symptoms in Patients with Coronary Heart Disease: An Individual Symptom Analysis

Background

Major depression is common in coronary heart disease (CHD) but challenging to diagnose. Instead of focusing on the overall diagnosis of depression, base rates of depressive symptoms could facilitate screening and management of psychopathology in CHD. The present study investigates the frequency of individual depressive symptoms in CHD and their impact on cardiac and subjective health.

Methods

In total, 1337 in- and outpatients with CHD were screened for depressive symptoms with the Patient Health Questionnaire-9 (PHQ-9) at three different cardiac treatment sites. Tables stratified by age and gender were designed to illustrate base rates of depressive symptoms. Multiple regression analyses adjusted for sociodemographic and clinical data were conducted to test associations between individual depressive symptoms and quality of life as well impairment caused angina pectoris and dyspnea.

Results

During the last 14 days, more than half of patients reported a loss of energy (74.9%, 95% Confidence Interval (CI): 70.6–79.2), sleeping problems (69.4%, 95% CI: 64.9–74.0), loss of interest (55.7%, 95% CI: 50.8–60.7). In contrast, psychomotor change (25.6%, 95%CI: 21.3–30.0), feelings of failure (21.9%, 95%CI: 17.7–26.0), suicidal ideations (14.1%, 95%CI: 10.7–17.6) were less frequently reported. Depending on the outcome, only particular depressive symptoms were highly associated with low quality of life and impairment caused by angina pectoris and dyspnea. Loss of energy was the only depressive symptom that reliably predicted all three outcomes.

Conclusions

Depressive symptoms in CHD are frequent but vary widely in terms of frequency. Findings underline the differential effects of individual depressive symptoms on cardiac health. Presented base rates of depressive symptoms offer clinicians a new way to judge the severity of individual depressive symptoms and to communicate individual PHQ-9 profiles with patients with respect to gender, age, cardiac symptoms and quality of life.

Anxiety and new onset of cardiovascular disease: critical review and meta-analysis

BACKGROUND

Anxiety has been associated with new-onset cardiovascular disease (CVD), but the quality of this relationship is unclear. Only if anxiety is a causal, independent cardiovascular risk factor might it be a target for CVD prevention.

AIMS

To determine and examine the independent association and causality between anxiety and incident CVD.

METHOD

PubMed, EMBASE and PsycINFO databases were searched up to October 2013. A review of Hill's criteria for causality and random effects meta-analysis were conducted of prospective, population-based studies examining anxiety and incident CVD in people free from CVD at baseline.

RESULTS

The meta-analysis comprised 37 papers (n = 1 565 699). The follow-up ranged from 1 to 24 years. Anxiety was associated with a 52% increased incidence of CVD (hazard ratio = 1.52, 95% CI 1.36-1.71). The risk seemed independent of traditional risk factors and depression. The evaluation of Hill's criteria largely argued in favour of causality.

CONCLUSIONS

Anxiety may be of interest for CVD prevention. Future research should examine biological and behavioural underpinnings of the association in order to identify targets for intervention.

Longitudinal associations between physical activity and depression scores in Swedish women followed 32 years

OBJECTIVE

Physical activity is negatively associated with depressive symptoms. However, few studies consider dynamic associations of changes in physical activity and reciprocal relationships. This study aimed to perform comprehensive evaluations of relationships between physical activity and depression scores in women followed from mid- to late life.

METHOD

The Prospective Population Study of Women in Gothenburg, Sweden, provided repeated measures of self-reported physical activity and depressive symptoms between 1974 and 2005 (baseline N = 676, 84.5% response rate). Depressive symptoms were assessed using the Montgomery-Åsberg Depression Rating Scale, and physical activity was evaluated by the Saltin-Grimby Physical Activity Level Scale. Latent growth curve analyses were used to evaluate associations of change, and cross-lagged models were used to study the reciprocal relationship between physical activity and depression scores.

RESULTS

At baseline, lower levels of physical activity were related to higher depression scores. Individuals with decreasing physical activity over time evidenced higher depression scores at 32-year follow-up. Higher average baseline depression score was related to declining levels of physical activity at subsequent examinations.

CONCLUSION

Reduced physical activity may be a long-term consequence of depression. It is important to address individual changes in physical activity and not merely absolute levels of physical activity in relationship to depression.

The Association between Neuroticism and Heart Rate Variability Is Not Fully Explained by Cardiovascular Disease and Depression

Neuroticism is associated with cardiovascular disease, autonomic reactivity, and depression. Here we address the extent to which neuroticism accounts for the excess heart disease risk associated with depression and test whether cardiac autonomic tone plays a role as mediator. Subjects were derived from a nationally representative sample (n = 1,255: mean age 54.5, SD = 11.5). Higher neuroticism was associated with reduced heart rate variability equally under rest and stress. The baseline structural equation model revealed significant paths from neuroticism to heart rate variability, cardiovascular disease and depression, and between depression and cardiovascular disease, controlling for age, sex, height, weight, and BMI. Dropping both the neuroticism to heart rate variability, and neuroticism to heart disease paths significantly reduced the model fit (p < .001 in each case). We conclude that neuroticism has independent associations with both autonomic reactivity and cardiovascular disease, over and above its associations with depression and other related variables.

The role of inflammatory markers in explaining the association between depression and cardiovascular hospitalisations

This study investigated whether inflammation may explain the relationship between depression and incident cardiovascular hospitalisations. Participants (55-85 years) completed baseline depression and physical assessment. Those without self-reported cardiovascular events were followed prospectively for hospital admissions for angina, myocardial infarction and cerebral infarction (median 937 days). Across 5140 person-years of risk (N = 1692), there were 47 incident cardiovascular hospitalisations (2.8 %). Controlling for age and gender, interleukin (IL)-6, C-reactive protein (CRP), body mass index (BMI) and waist-to-hip ratio were associated with future cardiovascular events. Mediation analysis showed that CRP accounted for 8.1 % and IL-6 10.9 % of the effect of depression on cardiovascular events, and including the indirect effect in the model substantially reduced the direct relationship between depression and cardiovascular hospitalisations. BMI and waist-to-hip ratio accounted for indirect effects of 7.7 and 10.4 %, respectively. Inflammatory markers partly explain the association between depression and cardiovascular events, although other shared factors also likely contribute.

Why would associations between cardiometabolic risk factors and depressive symptoms be linear?

In medical science, researchers mostly use the linear model to determine associations among variables, while in reality many associations are likely to be non-linear. Recent advances have shown that associations may be regarded as parts of complex, dynamic systems for which the linear model does not yield valid results. Using as an example the interdepencies between organisms in a small ecosystem, we present the work of Sugihara et al. in Science 2012, 338:496-500 who developed an alternative non-parametric method to determine the true associations among variables in a complex dynamic system. In this context, we discuss the work of Jani et al. recently published in BMC Cardiovascular Disorders, (personal communication is incorrect; we never communicated) describing a non-linear, J-shaped curve between a series of cardiometabolic risk factors and depression. Although the exact meaning of these findings may not yet be clear, they represent a first step in a different way of thinking about the relationships among medical variables, namely going beyond the linear model.Please see related article: http://www.biomedcentral.com/1471-2261/14/139.

Depression in context of low neuroticism is a risk factor for stroke: a 9-year cohort study

OBJECTIVE

Depression predicts stroke; however, meta-analyses show significant heterogeneity. We hypothesize that the risk of depression on incident stroke is conditional upon the relative contribution of vascular disease and of neuroticism in the underlying pathways to depression in a specific patient. We examined whether depression increases stroke in persons with low neuroticism and without preexisting cardiac disease.

METHODS

This was a population-based cohort study with 9-year follow-up (n = 2,050; ≥55 years, 52% female). The incidence of stroke was determined by self-report data as well as data from general practitioners and death certificates. Neuroticism was measured using the Dutch Personality Questionnaire and depression using the Center for Epidemiologic Studies-Depression scale. All data were analysed by Cox proportional hazards regression.

RESULTS

A total of 117 incident cases of stroke occurred during follow-up. Among persons with a history of cardiac disease (n = 401), depression predicted incident stroke independent of neuroticism level with a hazard ratio (HR) of 1.05 (95% confidence interval [CI] 1.01-1.10) (p = 0.02). In persons without cardiac disease (n = 1,649), depression and neuroticism interacted significantly in predicting incident stroke (p = 0.028). Stratified analyses showed that depression predicted incident stroke in those with low neuroticism, HR 1.05 (95% CI 1.00-1.09) (p = 0.033), but not in those with high neuroticism, HR 1.01 (95% CI 0.96-1.05) (p = 0.82).

CONCLUSIONS

In persons without preexistent cardiac disease, depression is only predictive for future stroke in absence of high neuroticism. This might be explained by the hypothesis that late-life depression in context of low neuroticism is a marker of subclinical vascular disease.

Childhood depression subscales using repeated sessions on Children's Depression Rating Scale - revised (CDRS-R) scores

BACKGROUND

Although acute treatments have been shown to be effective in treating early-onset depression, only one-third or thereabouts reach a remission within 3 months. Unfortunately, delayed time to remission in early-onset depression leads to poorer therapeutic outcomes. Clearly, there is a need to identify, diagnose, and provide effective treatment of a depressed patient quickly. A sophisticated understanding of depression subscales and their change over time with treatment could enhance pathways to individualized treatment approaches for childhood depression.

OBJECTIVE

Previous studies have found that the clinician-measured instrument, Children's Depression Rating Scale-Revised (CDRS-R) measures multiple subscales (or components) of depression. The aim of this study was to see how these subscales may change over the course of a 12-week study. This knowledge will help determine if dimensions/subscales of childhood depression (paralleling the adult literature) using the subscales derived from factor analysis procedure is useful.

METHODS

We examined two clinical trials in which youth (n=234) with major depressive disorder (MDD) were treated openly with fluoxetine for eight sessions spread over 12 weeks. The CDRS-R was completed based on clinician interviews with parent and child at each session. Classical test theory and component analysis with associated parallel analysis (oblique rotation) were conducted on each week's scores.

RESULTS

Although more factors were needed for the baseline and first two therapy sessions, a two-factor solution sufficed thereafter. Depressed facial affect, listless speech, and hypoactivity best defined Factor I, whereas sleep problems, appetite disturbance, physical symptoms, irritability, guilt, and weeping best defined Factor II. All other symptoms cross-loaded almost equally on the two factors. The scale's reliability (internal consistency) improved from baseline to exit sessions (α=0.65-0.91). As a result, the clinicians' assessments of the various symptoms became more highly related to one another. This caused the first eigenvalue to increase from 3.24 to 7.38 and the variance explained to increase (%) from 19% to 43% over sessions. These two factors may reflect 1) clinician-observed signs and 2) reported symptoms of depression.

CONCLUSIONS

Factor analysis of CDRS-R data in a single session consistently generates a complex and difficult to interpret structure of at least three factors. This makes it very difficult to understand what these factors measure. However, when gathered over additional sessions, the CDRS-R structure tends to simplify to two factors. The reasons for this simplification are as yet unclear and in need of further study.

Cardiovascular fitness in early adulthood and future suicidal behaviour in men followed for up to 42 years

BACKGROUND

Cardiovascular fitness influences many aspects of brain function. However, the relationship between cardiovascular fitness and suicidal behaviour is unknown. Therefore, we aimed to determine whether cardiovascular fitness at age 18 years is associated with future risk of suicide attempt/death.

METHOD

We performed a population-based Swedish longitudinal cohort study of male conscripts with no previous or ongoing mental illness (n = 1,136,527). The conscription examination, which took place during 1968-2005, included the cycle ergonometric test and tests of cognitive performance. Future risk of suicide attempt/death over a 5- to 42-year follow-up period was calculated with Cox proportional hazards models controlling for several confounders including familial factors.

RESULTS

At least one suicide attempt was recorded for 12,563 men. Death by suicide without a prior attempt was recorded in 4814 additional individuals. In fully adjusted models low cardiovascular fitness was associated with increased risk for future attempt/death by suicide [hazard ratio (HR) 1.79, 95% confidence interval (CI) 1.64-1.94]. The HR changed only marginally after exclusion of persons who received in-patient care for depression (HR 1.76, 95% CI 1.61-1.94). Poor performance on both the cardiovascular fitness and cognitive tests was associated with a fivefold increased risk of suicide attempt or suicide death (HR 5.46, 95% CI 4.78-6.24).

CONCLUSIONS

Lower cardiovascular fitness at age 18 years was, after adjustment for a number of potential confounders, associated with an increased risk of attempt/death by suicide in adulthood. It remains to be clarified whether interventions designed to improve fitness in teens can influence the risk of suicidal behaviour later in life.

Depression and cardiovascular disease: a clinical review

Cardiovascular disease (CVD) and depression are common. Patients with CVD have more depression than the general population. Persons with depression are more likely to eventually develop CVD and also have a higher mortality rate than the general population. Patients with CVD, who are also depressed, have a worse outcome than those patients who are not depressed. There is a graded relationship: the more severe the depression, the higher the subsequent risk of mortality and other cardiovascular events. It is possible that depression is only a marker for more severe CVD which so far cannot be detected using our currently available investigations. However, given the increased prevalence of depression in patients with CVD, a causal relationship with either CVD causing more depression or depression causing more CVD and a worse prognosis for CVD is probable. There are many possible pathogenetic mechanisms that have been described, which are plausible and that might well be important. However, whether or not there is a causal relationship, depression is the main driver of quality of life and requires prevention, detection, and management in its own right. Depression after an acute cardiac event is commonly an adjustment disorder than can improve spontaneously with comprehensive cardiac management. Additional management strategies for depressed cardiac patients include cardiac rehabilitation and exercise programmes, general support, cognitive behavioural therapy, antidepressant medication, combined approaches, and probably disease management programmes.

Cardio-metabolic risk factors and cortical thickness in a neurologically healthy male population: Results from the psychological, social and biological determinants of ill health (pSoBid) study

INTRODUCTION

Cardio-metabolic risk factors have been associated with poor physical and mental health. Epidemiological studies have shown peripheral risk markers to be associated with poor cognitive functioning in normal healthy population and in disease. The aim of the study was to explore the relationship between cardio-metabolic risk factors and cortical thickness in a neurologically healthy middle aged population-based sample.

METHODS

T1-weighted MRI was used to create models of the cortex for calculation of regional cortical thickness in 40 adult males (average age = 50.96 years), selected from the pSoBid study. The relationship between cardio-vascular risk markers and cortical thickness across the whole brain, was examined using the general linear model. The relationship with various covariates of interest was explored.

RESULTS

Lipid fractions with greater triglyceride content (TAG, VLDL and LDL) were associated with greater cortical thickness pertaining to a number of regions in the brain. Greater C reactive protein (CRP) and intercellular adhesion molecule (ICAM-1) levels were associated with cortical thinning pertaining to perisylvian regions in the left hemisphere. Smoking status and education status were significant covariates in the model.

CONCLUSIONS

This exploratory study adds to a small body of existing literature increasingly showing a relationship between cardio-metabolic risk markers and regional cortical thickness involving a number of regions in the brain in a neurologically normal middle aged sample. A focused investigation of factors determining the inter-individual variations in regional cortical thickness in the adult brain could provide further clarity in our understanding of the relationship between cardio-metabolic factors and cortical structures.

Birth order and post-traumatic stress disorder

OBJECTIVE

To compare the birth order of patients with post-traumatic stress disorder (PTSD) and adjustment disorder (AD) with population norms.

METHOD

83 PTSD patients and 104 AD control patients from a psychiatric trauma clinic were diagnosed according to DCR-10 guidelines. A family history was taken as to number of siblings, and their birth order. We compared the distribution of birth order for each patient group against birth order distributions expected by chance for the same years of birth using UK population-level birth order from the Office for National Statistics.

RESULTS

Psychiatric patients with PTSD were more likely to be from a large family, specifically to be the fifth child or later (OR 4.78, p < .001) and less likely to be the eldest child (OR .65, p < .001) than the general population in England and Wales. There were no differences for birth order between AD patients and the general population.

CONCLUSION

People with PTSD are more likely to be the youngest children from large families than expected from a random sample of people born in the same years. This association with birth order was not found for another psychiatric diagnosis AD from the same clinic. We discuss possible psychosocial and biological causes, and implications for further research.