A review of candidate pathways underlying the association between asthma and major depressive disorder

Depression and risk of incident asthma in adults. The CARDIA study

RATIONALE

Asthma is associated with depression, but the temporality of the association has not been established.

OBJECTIVES

To examine the association between prevalent elevated depressive symptoms and incident asthma, and between prevalent asthma and incident elevated depressive symptoms in a cohort of young and middle-aged adults.

METHODS

We examined the longitudinal association between asthma and depressive symptoms bidirectionally in the Coronary Artery Risk Development in Young Adults (CARDIA) cohort. First, 3,614 participants, free of asthma, were classified by elevated depressive symptoms at the CARDIA Year-5 exam (n = 856 elevated vs. 2,758 not elevated; ages 23-35 yr) and followed for 20 years to incident asthma. Then, 3,016 participants, free of elevated depressive symptoms, were classified by self-reported current asthma status (n = 188 prevalent vs. 2,828 not prevalent) at the CARDIA Year-5 exam and followed for 20 years until onset of elevated depressive symptoms.

MEASUREMENTS AND MAIN RESULTS

The relative hazard of incident asthma among those with elevated depressive symptoms was 1.26 (95% confidence interval [CI] = 1.02-1.56) after adjustment for covariates. When depressive status was modeled as the total number of reports of elevated depressive symptoms before the onset of asthma, the adjusted hazard ratio was 1.15 (95% CI = 1.02-1.29). The hazard of incident elevated depressive symptoms for those with asthma was no different than the hazard in those without asthma (adjusted hazard ratio = 0.92; 95% CI = 0.70-1.20).

CONCLUSIONS

This longitudinal observational study points to depression as a marker of risk for incident adult-onset asthma. On the other hand, prevalent asthma is not associated with incident adult-onset depression.

Mental health and asthma in China: the Guangzhou Biobank Cohort Study

BACKGROUND

There is consistent evidence of the co-occurrence of poor mental health and asthma in Western populations. Since the experience and expression of mental health is partly culturally determined, it is of interest to examine if similar associations are found in other cultural settings. In that regard, very little is known about the association between mental health and asthma in Asian countries, such as China.

PURPOSE

The aim of this study was to investigate the relationship between mental health and asthma in a large sample from China.

METHOD

We used data from the Guangzhou Biobank Cohort Study phase 3 (n = 9,280). Participants reported physician-diagnosed asthma. Mental health measures included the 15-item Chinese version of the Geriatric Depression Scale (GDS-C) and the SF-12 Mental Component Summary (MCS) score. We compared the prevalence of asthma by GDS-C and MCS scores by estimating prevalence ratios (PRs) and their corresponding 95% confidence intervals (95% CI), using Poisson regression.

RESULTS

Compared to those without depression, the prevalence of asthma was higher in those with moderate or severe depression levels (PR = 2.63, 95% CI = 1.58–4.40 and PR = 4.43, 95% CI = 1.62–12.09, p for trend ≤0.0001). The prevalence of asthma increased by 46% with every 1 standard deviation increase of the GDS-C score (PR = 1.46, 95% CI = 1.24–1.73). The MCS score was not associated with asthma.

CONCLUSION

Depressive symptoms were associated with asthma prevalence in a Chinese population. Further research into the mechanism and potential directions of causality is warranted.

Asthma and depression: the Cooper Center Longitudinal Study

BACKGROUND

Prior research suggests a possible association between asthma and depression.

OBJECTIVE

To examine the association between asthma and depressive symptoms, controlling for asthma medications, lung function, and overall health.

METHODS

We conducted a cross-sectional study of 12,944 adults who completed physician-based preventive health examinations at the Cooper Clinic from 2000 to 2012. Information on medical histories, including asthma and depression, and medications were collected. Participants reported overall health status, completed spirometry testing, and underwent depression screening using the 10-item Center for Epidemiologic Studies Depression Scale (CES-D). Dependent variables of current depressive symptoms (CES-D scores ≥10) and lifetime history of depression were separately modeled using logistic regression with independent variables, including demographics, spirometry, asthma controller medications, and patient-reported health status.

RESULTS

The sample was predominantly white and well educated. The prevalence of asthma was 9.0%. Asthma was associated with an odds ratio (OR) of 1.41 (95% CI, 1.16-1.70; P < .001) of current depressive symptoms based on CES-D score. Asthma was also associated with lifetime history of depression (OR, 1.66; 95% CI, 1.40-1.95; P < .001). Neither lung function nor asthma controller medications were significantly associated with depression.

CONCLUSION

Asthma was associated with increased prevalence of current depressive symptoms and lifetime depression in a large sample of relatively healthy adults. These findings suggest that the increased likelihood of depression among patients with asthma does not appear to be exclusively related to severe or poorly controlled asthma. People with asthma, regardless of severity, may benefit from depression screening in clinical settings.

Atopic disorders and depression: findings from a large, population-based study

BACKGROUND

Atopy, a common disorder characterized by a sensitivity to allergic reactions, affects a large proportion of the adult population and, as with depression, is associated with immune-inflammatory pathway changes. We sought to determine the role of atopic disorders in depression using data from a randomly-selected, population-based study of men and women.

METHODS

Cross-sectional data derived from the Geelong Osteoporosis Study for 942 males and 1085 females were analyzed. Depression [major depressive disorder (MDD), minor depression and dysthymia] was assessed using the Structured Clinical Interview for DSM-IV-TR Research Version, Non-patient edition. Data on medical conditions, including atopic disorders (asthma, hay fever and eczema), smoking status, alcohol consumption, socioeconomic status, and physical activity were documented by self-report. Logistic regression modeling was used to explore the associations between atopic disorders and depression.

RESULTS

Atopic disorders were associated with a 59% increased likelihood of depression [gender and smoking-adjusted odds ratio (OR) 1:50, 95% CI 1.20-1.97]. Sub-group analyses revealed a similar pattern for those with MDD [gender and smoking-adjusted OR 1:54, 95% CI 1.22-1.94]. These associations were independent of socio-demographic characteristics, clinical and lifestyle factors.

LIMITATIONS

Reliance on self-report for allergic symptoms and cross-sectional nature of study.

CONCLUSION

This population-based study provides evidence of the potential contribution of allergic disorders to depression. Further research is required to elucidate the direction of this association and to further explicate its underlying physiology, including immune-inflammation markers.

Coexisting chronic conditions associated with mortality and morbidity in adult patients with asthma

OBJECTIVE

Many asthma patients suffer from chronic conditions other than asthma. We investigated the specific contribution of common comorbidities on mortality and morbidity in adult asthma.

METHODS

In an observational study of adults with incident asthma identified between 1999 and 2003 using National Veterans Affairs and Centers for Medicare and Medicaid Services encounter databases (n = 25 975, follow-up 3.0 ± 1.7 years), association between 13 most prevalent comorbidities (hypertension, ischemic heart disease (IHD), osteoarthritis, rheumatoid arthritis, diabetes, mental disorders, substance/drug abuse, enlarged prostate, depression, cancer, alcoholism, HIV and heart failure) and four conditions previously associated with asthma (sleep apnea, gastroesophageal reflux disease (GERD), rhinitis and sinusitis) and mortality, hospitalizations and asthma exacerbations were assessed using multivariate regression analyses adjusted for other clinically important covariates.

RESULTS

HIV followed by alcoholism and mental disorders among 18-45-years old, and heart failure, diabetes, IHD and cancer among those ≥ 65 years old were associated with an increased risk of all-cause mortality. Many conditions were associated with increased risk for all-cause hospitalizations, but the increased risk was consistent across all ages for mental disorders. For asthma exacerbations, mental disorder followed by substance abuse and IHD were associated with increased risk among those 18-45 years old, and chronic sinusitis, mental disorder and IHD among those ≥ 65-years old. GERD was associated with decreased risk for asthma exacerbation in all ages.

CONCLUSIONS

Many comorbidities are associated with poor outcome in adult asthmatics and their effect differs by age. Mental disorders are associated with increased risk of mortality and morbidity across ages.

Excess risk of chronic physical conditions associated with depression and anxiety

BACKGROUND

Depression and anxiety have been reported to be associated with chronic physical conditions. We examined the excess risk of chronic physical conditions associated with depression and/or anxiety within a multivariate framework controlling for demographic and modifiable lifestyle risk factors.

METHODS

We used a retrospective cross-sectional study design. Study participants were adults aged 22-64 years from 2007 and 2009 Medical Expenditure Panel Survey. We defined presence of depression-anxiety based on self-reported depression and anxiety and classified adults into 4 groups: 1) depression only; 2) anxiety only; 3) comorbid depression and anxiety 4) no depression and no anxiety. We included presence/absence of arthritis, asthma, chronic obstructive pulmonary disorder, diabetes, heart disease, hypertension, and osteoporosis as dependent variables. Complementary log-log regressions were used to examine the excess risk associated with depression and/or anxiety for chronic physical conditions using a multivariate framework that controlled for demographic (gender, age, race/ethnicity) and modifiable lifestyle (obesity, lack of physical activity, smoking) risk factors. Bonferroni correction for multiple comparisons was applied and p ≤0.007 was considered statistically significant.

RESULTS

Overall, 7% had only depression, 5.2% had only anxiety and 2.5% had comorbid depression and anxiety. Results from multivariable regressions indicated that compared to individuals with no depression and no anxiety, individuals with comorbid depression and anxiety, with depression only and with anxiety only, all had higher risk of all the chronic physical conditions. ARRs for comorbid depression and anxiety ranged from 2.47 (95% CI: 1.47, 4.15; P = 0.0007) for osteoporosis to 1.64 (95% CI: 1.33, 2.04; P < 0.0001) for diabetes. Presence of depression only was also found to be significantly associated with all chronic conditions except for osteoporosis. Individuals with anxiety only were found to have a higher risk for arthritis, COPD, heart disease and hypertension.

CONCLUSION

Presence of depression and/or anxiety conferred an independent risk for having chronic physical conditions after adjusting for demographic and modifiable lifestyle risk factors.

The association of depressive symptoms and pulmonary function in healthy adults

OBJECTIVE

Chronic lung disease is exacerbated by comorbid psychiatric issues and treatment of depression may improve disease symptoms. We sought to add to the literature as to whether depression is associated with pulmonary function in healthy adults.

METHODS

In 2551 healthy adults from New York State, we studied the association of depression via the Center for Epidemiologic Studies Depression scale (CES-D) scale score and forced expiratory volume in 1 second (FEV1) and forced vital capacity (FVC) using general linear models and a cross-sectional design.

RESULTS

We identified statistically significant inverse trends in FEV1, FVC, FEV1%, and FVC% by CES-D category, especially in ever-smokers and men. When adjusted for covariates, the difference in FEV1 and FEV1% for smokers with more than 18.5 lifetime pack-years from CES-D scores 0 to 3 to 16 or more (depressed) is approximately 0.25 l and 5.0% (adjusted p values for trend are <.001 and .019, respectively). In men, we also observed statistically significant inverse trends in pulmonary function with increasing CES-D.

CONCLUSIONS

We identified an inverse association of depressive symptoms and pulmonary function in healthy adults, especially in men and individuals with a heavy smoking history. Further studies of these associations are essential for the development and tailoring of interventions for the prevention and treatment of chronic lung disease.

Examining the relationship between depression and asthma exacerbations in a prospective follow-up study

BACKGROUND

Although depression has been linked with asthma, its relationship with asthma exacerbations, including emergency department (ED) visits and oral steroid (OS) use, has not been well documented. The aim is to investigate whether depression increases exacerbations among patients with asthma.

METHOD

The study included 568 participants with asthma who were between 18 and 56 years old, were taking an inhaled corticosteroid, and participated in baseline and follow-up surveys. Surveys and medical records from a large, health system were collected as part of the Adherence Feedback for Improving Respiratory Medication Use trial. Number of ED visits and OS prescription fills for asthma were calculated for 12-month periods before and after the follow-up survey. Depression was measured using a standardized two-item instrument. Negative binomial regression and modified proportional hazards models were used.

RESULTS

Among patients with asthma, those who had depression (n = 187; 32.9%) were at increased risk for an asthma-related ED visit (adjusted relative risk = 1.96, 95% confidence interval [CI] = 1.02-3.75), but not an OS fill (adjusted relative risk = 0.98; 95% CI = 0.72-1.32). Participants with depression and asthma who received psychiatric treatment via antidepressant medication (n = 126; 22.2%) or psychotherapy (n = 39; 6.9%) were more likely to have an ED visit (medication hazard ratio = 2.09, 95% CI = 1.35-3.25; psychotherapy hazard ratio = 2.07, 95% CI = 1.38-3.22).

CONCLUSIONS

This study suggests a temporal relationship between depression and asthma-related ED visits. Research and practice must consider the importance of these comorbid conditions. Trial Registration ClinicalTrials.gov identifier: NCT00459368.

Psychosocial factors and behavioral medicine interventions in asthma

OBJECTIVE

This review examines the evidence for psychosocial influences in asthma and behavioral medicine approaches to its treatment.

METHOD

We conducted a systematic review of the literature on psychosocial influences and the evidence for behavioral interventions in asthma with a focus on research in the past 10 years and clinical trials. Additional attention was directed at promising new developments in the field.

RESULTS

Psychosocial factors can influence the pathogenesis and pathophysiology of asthma, either directly through autonomic, endocrine, immunological, and central nervous system mechanisms or indirectly through lifestyle factors, health behaviors, illness cognitions, and disease management, including medication adherence and trigger avoidance. The recent decade has witnessed surging interest in behavioral interventions that target the various pathways of influence. Among these, self-management training, breathing training, and exercise or physical activation programs have proved particularly useful, whereas other essential or promising interventions, such as smoking cessation, dietary programs, perception and biofeedback training, and suggestive or expressive psychotherapy, require further, more rigorous evaluation. Given the high comorbidity with anxiety and mood disorders, further evaluation of illness-specific cognitive behavior therapy is of particular importance. Progress has also been made in devising community-based and culturally tailored intervention programs.

CONCLUSION

In concert with an essential medication treatment, behavioral medicine treatment of asthma is moving closer toward an integrated biopsychosocial approach to disease management.

Selection of suitable housekeeping genes for real-time quantitative PCR in CD4(+) lymphocytes from asthmatics with or without depression

OBJECTIVE

No optimal housekeeping genes (HKGs) have been identified for CD4(+) T cells from non-depressive asthmatic and depressive asthmatic adults for normalizing quantitative real-time PCR (qPCR) assays. The aim of present study was to select appropriate HKGs for gene expression analysis in purified CD4(+) T cells from these asthmatics.

METHODS

Three groups of subjects (Non-depressive asthmatic, NDA, n = 10, Depressive asthmatic, DA, n = 11, and Healthy control, HC, n = 10 respectively) were studied. qPCR for 9 potential HKGs, namely RNA, 28S ribosomal 1 (RN28S1), ribosomal protein, large, P0 (RPLP0), actin, beta (ACTB), cyclophilin A (PPIA), glyceraldehyde-3-phosphate dehydrogenase (GAPDH), phosphoglycerate kinase 1 (PGK1), beta-2-microglobulin (B2M), glucuronidase, beta (GUSB) and ribosomal protein L13a (RPL13A), was performed. Then the data were analyzed with three different applications namely BestKeeper, geNorm, and NormFinder.

RESULTS

The analysis of gene expression data identified B2M and RPLP0 as the most stable reference genes and showed that the level of PPIA was significantly different among subjects of three groups when the two best HKGs identified were applied. Post-hoc analysis by Student-Newman-Keuls correction shows that depressive asthmatics and non-depressive asthmatics exhibited lower expression level of PPIA than healthy controls (p<0.05).

CONCLUSIONS

B2M and RPLP0 were identified as the most optimal HKGs in gene expression studies involving human blood CD4(+) T cells derived from normal, depressive asthmatics and non-depressive asthmatics. The suitability of using the PPIA gene as the HKG for such studies was questioned due to its low expression in asthmatics.

The association of asthma and wheezing with major depressive episodes: an analysis of 245 727 women and men from 57 countries

BACKGROUND

Epidemiological studies have shown that asthma is positively associated with depression. Most of this evidence stems from individual studies conducted in Western populations (e.g. Europe, North America and Australia). It is still unclear whether such findings generalize to non-Western countries. To address this question, the present study investigated the association of asthma and wheezing with depression in a large multi-national sample.

METHODS

We used data from the 2002 World Health Survey. Participants reported physician-diagnosed asthma and attacks of wheezing within the past 12 months. Questions on depressive symptoms, their duration and persistence were used to define presence of a major depressive episode (MDE) within the past 12 months. ORs and 95% CIs were estimated by logistic regression for the entire sample, by continent (Australia, Europe, South America, Asia and Africa) and by country. Complete information was available for 57 countries.

RESULTS

Both asthma and wheezing were associated with MDE in the entire sample (OR=2.37, 95% CI=2.10-2.66 and OR=3.06, 95% CI=2.75-3.40, respectively). Similar associations were found for all continents with generally stronger ORs in South America, Asia and Africa for both asthma (ORs ≥ 1.8) and wheezing (ORs  ≥ 2.8). On the country level, wheezing showed a consistent pattern of association with MDE. Similar patterns were found for asthma.

CONCLUSIONS

Despite a range of country differences that could affect the association of asthma with depression, such as access to health care, the results of this study indicate that the co-occurrence of asthma and depression is a universal phenomenon.

Inhibition of allergic inflammation by supplementation with 5-hydroxytryptophan

Clinical reports indicate that patients with allergy/asthma commonly have associated symptoms of anxiety/depression. Anxiety/depression can be reduced by 5-hydroxytryptophan (5-HTP) supplementation. However, it is not known whether 5-HTP reduces allergic inflammation. Therefore, we determined whether 5-HTP supplementation reduces allergic inflammation. We also determined whether 5-HTP decreases passage of leukocytes through the endothelial barrier by regulating endothelial cell function. For these studies, C57BL/6 mice were supplemented with 5-HTP, treated with ovalbumin fraction V (OVA), house dust mite (HDM) extract, or IL-4, and examined for allergic lung inflammation and OVA-induced airway responsiveness. To determine whether 5-HTP reduces leukocyte or eosinophil transendothelial migration, endothelial cells were pretreated with 5-HTP, washed and then used in an in vitro transendothelial migration assay under laminar flow. Interestingly, 5-HTP reduced allergic lung inflammation by 70-90% and reduced antigen-induced airway responsiveness without affecting body weight, blood eosinophils, cytokines, or chemokines. 5-HTP reduced allergen-induced transglutaminase 2 (TG2) expression and serotonylation (serotonin conjugation to proteins) in lung endothelial cells. Consistent with the regulation of endothelial serotonylation in vivo, in vitro pretreatment of endothelial cells with 5-HTP reduced TNF-α-induced endothelial cell serotonylation and reduced leukocyte transendothelial migration. Furthermore, eosinophil and leukocyte transendothelial migration was reduced by inhibitors of transglutaminase and by inhibition of endothelial cell serotonin synthesis, suggesting that endothelial cell serotonylation is key for leukocyte transendothelial migration. In summary, 5-HTP supplementation inhibits endothelial serotonylation, leukocyte recruitment, and allergic inflammation. These data identify novel potential targets for intervention in allergy/asthma.

Prevalence and Impact of Mental and Physical Comorbidity in the Adult Singapore Population

Introduction: This study aims to assess the prevalence rates of mental disorders and chronic medical conditions in the Singapore resident population, and examine their association and respective impact on the quality of life. Materials and Methods: A household survey was carried out on a nationally representative sample of the adult (18 years and above) resident population. The main instrument used to establish the diagnosis of mental disorders is the World Mental Health Composite International Diagnostic Interview (WMH-CIDI). The mental disorders included in study were major depressive disorder, bipolar disorder, generalised anxiety disorder, obsessive compulsive disorder, alcohol abuse and alcohol dependence. Respondents were asked if they had any of the chronic medical conditions from a list of 15 conditions. Health-related quality of life was assessed with the EQ-5D. Results: Of the 6616 respondents, the lifetime prevalence of mental disorders was 12.0%, and that of chronic medical disorders were 42.6% and those with comorbid mental and medical disorders was 6.1%. The prevalence of any physical disorder in this population was high (42.6%). Among those with chronic physical disorders, 14.3% also had a mental disorder, and among those with mental disorders, more than half (50.6%) had a medical disorder. Most of the mental disorders were not treated. Males, Indians, older people, and those who were separated or divorced were more likely to have comorbidity. The health-related quality of life was significant worse in those with both mental and medical disorders compared to those with either mental or medical disorder. Conclusion: Our study re-emphasised the common occurrence of mental and medical disorders and the importance for an integrated care system with the capability to screen and treat both types of disorders. It also identified certain subpopulations which are more likely to have comorbidity for which a more targeted intervention could be planned. Key words: Chronic conditions, Ethnicity, Health-related quality of life, Marital status

Effect of current depression on the association of work-related asthma with adverse asthma outcomes: a cross-sectional study using the Behavioral Risk Factor Surveillance System

BACKGROUND

Depression has been associated with a decreased level of asthma control. The aim of our study was to examine associations between health-professional diagnosed work-related asthma (WRA) and current depression and the effect of current depression on the associations of WRA with adverse asthma outcomes.

METHOD

We analyzed data from the 2006 and 2008 Behavioral Risk Factor Surveillance System Asthma Call-Back Survey and the Anxiety and Depression Module conducted in 25 states and District of Columbia for ever-employed adults with current asthma. We computed weighted proportions and prevalence ratios adjusted for age, sex, race/ethnicity, education, current employment status, and smoking status. Survey participants who were ever told by a doctor or other health professional that their asthma was related to any job they ever had were determined to have WRA. Participants with current depression were identified using self-report of depressive symptoms.

RESULTS

Of ever-employed adults with current asthma, an estimated 9.1% had WRA and 17.0% had current depression. Persons with WRA were significantly more likely than those with non-WRA to have current depression. Persons with either WRA, current depression, or both WRA and current depression were significantly more likely to have adverse asthma outcomes than persons with asthma and neither condition. The associations with adverse asthma outcomes were stronger when both current depression and WRA were present.

LIMITATIONS

This is a cross-sectional and hypothesis-generating study.

CONCLUSIONS

Depression may play an important role in asthma management and should be considered when assessing patients with asthma and, in particular, those with WRA.

Depression prevalence and associated factors among Alaska Native people: the Alaska education and research toward health (EARTH) study

BACKGROUND

Few studies have investigated depression among Alaska Native people (ANs). Depression prevalence and associated factors among EARTH Alaska study participants are described.

METHODS

The nine-item Patient Health Questionnaire (PHQ-9) assessed depression among 3771 ANs. Participants with PHQ-9 scores≥10 out of 27 were classified as positive for depression. Logistic regression analyses evaluated odds of scoring positive versus negative for depression by demographic, cultural, then health and lifestyle factors.

RESULTS

Twenty percent of women and 13% of men scored positive for depression. Univariate and multivariate models were fit separately for men and women. Among demographic factors, below median income was associated with positive depression scores for both genders. Among men, odds of depression were higher if unmarried and/or if highest educational level was less than high school. Women 34 to 59 years of age had increased odds of scoring positive. Little or no identification with tribal tradition was associated with increased odds of depression in women and decreased odds in men. For both genders, chronic physical conditions and poorer self-reported health were associated with positive depression scores then binge alcohol drinking and current tobacco use increased odds of depression among women only.

LIMITATIONS

Factors analyzed were self-reported without clinician follow-up in a non-random convenience sample of adults.

CONCLUSIONS

Depression is common among ANs with rates comparable to other indigenous cross-sectional investigations. Depression is associated with lower income and poorer physical health. Prevention and intervention efforts should consider gender as other associated factors varied between men and women.

Specificity in the association of anxiety, depression, and atopic disorders in a community sample of adolescents

The specificity of relationships between anxiety and depressive symptoms, with each of the major atopic disorders of asthma, allergic rhinitis (AR), and atopic dermatitis (AD) was systematically investigated within a single study sample. Participants included 367 adolescents who participated in a community, longitudinal study investigating risk factors for the development of psychiatric and physical health problems. Mental health symptoms were assessed at 7, 9, 11, and 13 years of age. Lifetime history of atopic disorders was assessed by parent report at age 13. Analysis of variance was used to investigate the specificity of the associations between anxiety and depression, and each of the atopic disorders. Results indicated that anxiety was associated with a lifetime history of atopic disorders as a group. The association was significantly strengthened when controlling for depression and externalizing psychiatric symptoms. Among atopic disorders, "pure" anxiety was associated with asthma and AR, and having both asthma and AR strengthened the association compared to having either disorder alone. The association of "pure" anxiety with asthma and AR is consistent with existing data suggesting a relationship between anxiety and respiratory disorders. Having both asthma and AR appeared to confer an additive "dose effect" on the strength of the association. The lack of an association with depression suggests that other factors may contribute to the differential expression of anxiety and depression with atopic disorders. Findings demonstrate the importance of assessing the impact of co-morbid psychiatric symptoms and atopic disorders within individual studies to determine the specificity of underlying relationships between these conditions.

Association of depression, psycho-social stress and acculturation with respiratory disease among Puerto Rican adults in Massachusetts

To assess associations between acculturation, depression, and self-reported stress score with reported diagnosis of respiratory disease (RD) in Puerto Rican adults, participants (N = 1,168) were identified from areas of high Hispanic density in the Boston, MA metropolitan area. Eligible participants were interviewed in the home by bilingual interviewers in either Spanish or English. Scales included topics ranging from general background to depressive symptomatology. Respiratory disease was self-reported and checked against prescribed medication. More than one-third (37.8%) of subjects reported doctor-diagnosed RD. A final binary logistical regression model (N = 850), which was adjusted for potential confounders (sex, age, education, poverty) showed that RD was significantly associated with psychological acculturation (OR = 1.97, P = 0.005), depressive symptomatology (OR = 1.52, P = 0.03) high perceived stress score (OR = 1.97, P = 0.009), and current smoking (OR = 1.61, P = 0.03). Significant inverse associations included a high level of language acculturation (OR = 0.65, P = 0.03), light (OR = 0.67, P = 0.01) and moderate to heavy physical activity versus sedentary physical activity (OR = 0.40, P = 0.03). We found self reported physician diagnosed RD was associated with high perceived stress and depression, as well as higher levels of psychological acculturation. Longitudinal research is needed to determine if there is a causal pathway for these associations.

The association between idiopathic environmental intolerance and psychological distress, and the influence of social support and recent major life events

OBJECTIVES

Idiopathic environmental intolerance (IEI) is a disorder characterized by non-specific symptoms attributed to common airborne chemicals. Increasing evidence points to an association between IEI and symptoms of psychological distress. However, whether other risk factors influence this association has not been clarified. The objective of this study was to examine the association between psychological distress and IEI and to determine whether the association is confounded by social support and major life events.

METHODS

Data were collected by postal questionnaires; other results from the study have been published previously in this journal. The study included participants from a general population-based study who had reported symptoms of chemical sensitivities (n = 787) and two patient groups. The first patient group (n = 101) included individuals who had contacted the Danish Research Centre for Chemical Sensitivities, and the second included individuals who had been diagnosed with environmental intolerance (n = 136). Multiple, hierarchical linear regression analyses were conducted with four IEI-related domains, i.e., mucosal and CNS symptoms, chemical intolerances and social consequences, as the dependent variables, and psychological distress, social support and major life events as the independent variables.

RESULTS

Our study confirmed positive and statistically significant associations between psychological distress and IEI. The associations remained statistically significant after adjusting for major life events and social support.

CONCLUSIONS

The results suggest that the association between IEI and psychological distress cannot be explained by known risk factors. More studies, including longitudinal studies, are needed to determine the role of psychological distress in the development and course of IEI.

Immune suppression and immune activation in depression

Depression has been characterized as a disorder of both immune suppression and immune activation. Markers of impaired cellular immunity (decreased natural killer cell cytotoxicity) and inflammation (elevated IL-6, TNFα, and CRP) have been associated with depression. These immunological markers have been associated with other medical illnesses, suggesting that immune dysregulation may be a central feature common to both depression and to its frequent medical comorbidities. Yet the significant associations of findings of both immune suppression and immune activation with depression raise questions concerning the relationship between these two classes of immunological observations. Depressed populations are heterogeneous groups, and there may be differences in the immune profiles of populations that are more narrowly defined in terms of symptom profile and/or demographic features. There have been few reports concurrently investigating markers of immune suppression and immune activation in the same depressed individuals. An emerging pre-clinical literature suggests that chronic inflammation may directly contribute to the pathophysiology of immune suppression in the context of illnesses such as cancer and rheumatoid arthritis. This literature provides us with specific immunoregulatory mechanisms mediating these relationships that could also explain differences in immune disturbances between subsets of depressed individuals We propose a research agenda emphasizing the assessment of these immunoregulatory mechanisms in large samples of depressed subjects as a means to define the relationships among immune findings (suppression and/or activation) within the same depressed individuals and to characterize subsets of depressed subjects based on shared immune profiles. Such a program of research, building on and integrating our knowledge of the psychoneuroimmunology of depression, could lead to innovation in the assessment and treatment of depression and its medical comorbidities.

Depressive symptoms, social support, and risk of adult asthma in a population-based cohort study

OBJECTIVE

To investigate the association between depressive symptoms, social support, and prevalent as well as incident asthma. Depressive symptoms and social support may affect the development of asthma. This relationship could be mediated by health behaviors and/or inflammatory processes. Evidence from prospective cohort studies on depressive symptoms and social support in relation to asthma risk in adults remains sparse.

METHODS

Between 1992 and 1995, a population-based sample of 5114 middle-aged adults completed questionnaires covering depressive symptoms, social support, self-reported asthma, and potential confounders. Among those alive in 2002/2003, 4010 (83%) were followed-up by questionnaires. Associations with prevalent and incident asthma were estimated by prevalence ratios (PR) and risk ratios (RR) along with corresponding 95% confidence intervals (CIs), using Poisson regression. PRs and RRs were adjusted for demographics, family history of asthma, smoking, alcohol consumption, body mass index, and physical exercise.

RESULTS

Cross-sectional analyses indicated that the prevalence of asthma was positively associated with depressive symptoms and inversely related to social support. Prospective analysis suggested a 24% increased risk of asthma with each 1-standard deviation increase in depressive symptoms (RR, 1.24; 95% CI, 1.02, 1.50), whereas the social support z score showed an inverse association with asthma incidence (RR, 0.71; 95% CI, 0.58, 0.88). Analyses with tertiles suggested similar, but nonsignificant, associations. Omitting health-related life-style variables from the multivariable models did not substantially alter these associations.

CONCLUSIONS

Risk of adult asthma was found to increase with depressive symptoms and to decrease with social support. These associations do not seem to be explained by health-related life-style factors.

Neuroimmune mechanisms of cytokine-induced depression: current theories and novel treatment strategies

The relationships between immune and neural function are an increasingly important area of study for neuropsychiatric disorders, in particular depression. This is exemplified by the growing number of publications on cytokines and depression during the last 10 years, as compared to earlier decades. This review summarizes the current theories and novel treatment strategies for depression, with a focus on cytokine-induced depression. Neuroimmune mechanisms are now viewed as central to the development of depressive symptoms and emerging evidence is beginning to identify the neural circuits involved in cytokine-induced depression. The current diagnostic categories for depression, as defined by the Diagnostic and Statistical Manual of Mental Disorders, however, are not etiologically or biologically derived, and it has been proposed that "depression", likely reflects multiple pathogeneses leading to varying symptom constellations. As we move toward a better biological understanding of depression-related symptom constellations or syndromes, the term "depression" may prove inadequately broad, and an integration of interdisciplinary literatures will increase in importance. Future research should aim to characterize these depression-related symptom constellations or syndromes better with the goal of optimizing treatment strategies.

Analysis of behavior-related adverse experiences in clinical trials of montelukast

BACKGROUND

Frequencies of behavior-related adverse experiences (BRAEs) in controlled clinical studies of leukotriene modifier drugs have not been summarized.

OBJECTIVE

We sought to compare the frequency of BRAEs in patients receiving montelukast or placebo in a retrospective analysis of Merck clinical trial data.

METHODS

An adverse experience database was constructed to include all double-blind, placebo-controlled trials of montelukast meeting prespecified criteria. BRAEs (described using the Medical Dictionary for Regulatory Activities controlled vocabulary dictionary) were prespecified to include any term in the Psychiatric Disorders System Organ Class, selected terms related to general disorders, and terms related to akathisia. Frequencies of BRAEs (overall, leading to study discontinuation, and/or serious) were summarized. Analyses estimated the odds ratios (ORs) for montelukast versus placebo based on the frequency of patients with BRAEs in each study.

RESULTS

In total 35 adult and 11 pediatric placebo-controlled trials were included; 11,673 patients received montelukast, 8,827 received placebo, and 4,724 received active control. The frequency of patients with 1 or more BRAEs was 2.73% and 2.27% in the montelukast and placebo groups, respectively; the OR for montelukast versus placebo was 1.12 (95% CI, 0.93-1.36). The frequency of patients with a BRAE leading to study discontinuation was 0.07% and 0.11% in the montelukast and placebo groups, respectively (OR, 0.52; 95% CI, 0.17-1.51). The frequency of patients with a BRAE considered serious was 0.03% in both treatment groups.

CONCLUSION

Reports of BRAEs were infrequent in clinical trials of montelukast. Those leading to study discontinuation or considered serious were rare. Frequencies were similar regardless of treatment group.