Research reportAtopic disorders and depression: Findings from a large, population-based study
Introduction
Atopy is defined as the presence of elevated immunoglobulin E (IgE) levels associated with exposure to allergens commonly occurring in the environment (Johansson et al., 2004). This disorder typically results in the development of allergic symptoms such as eczema, dermatitis, allergic rhinitis/hay fever, allergic conjunctivitis or asthma. Interestingly, its prevalence has increased over the past 20 to 30 years in many parts of the world, including Western nations like the United States and Australia (Jarvis and Burney, 1998); the cause of which is relatively unknown. Historically, atopic disorders have been considered to be “psychosomatic” in origin (Niemeier et al., 2002), but recently the concept of psycho-neuro-immune-endocrinology, a discipline that studies the close relations between mind, brain, immune and hormonal system, has reformulated perspectives on these relationships (Liezmann et al., 2011) and atopic disorders are now considered to be primarily due to immune dysregulation.
Studies investigating immune system functioning in patients with depression have observed activated inflammatory, cell-mediated immune (CMI) and oxidative and nitrosative stress (O&NS) pathways in these individuals (Maes et al., 2011, Maes, 2011, Dowlati et al., 2010). This evidence comprises signs of inflammation, such as increased levels of pro-inflammatory cytokines [e.g. interleukin-1 (IL-1), IL-6 and tumor necrosis factor-α (TNFα)], acute phase proteins [e.g. haptoglobin and C-reactive protein (CRP)] and complement factors; CMI and Th1 cell activation, with increased levels of interferon-(IFN)γ and neopterin, lower concentrations of T regulatory (Treg) cells, oxidative damage to membrane fatty acids and DNA, and nitrosative modifications of proteins (Maes, 1995, Pasco et al., 2010, Maes et al., 2011, Li et al., 2010). Furthermore, the incidence of depression is considerably higher among medically ill patients, particularly in those diseases associated with immune activation (Clarke and Currie, 2009, Sanna et al., 2013), thus providing a rationale for this study.
Antidepressants, such as tricyclic antidepressants and selective serotonin reuptake inhibitors, have specific negative immune-regulatory effects by lowering the production of IFNγ and IL-1β, and increasing the production of IL-10 and the levels of Treg cells (Maes et al., 1999, Himmerich et al., 2010). Many drugs with anti-inflammatory effects augment the clinical efficacy of antidepressants in the treatment of depression (Maes et al., 2012). For example, TNFα blockers, such as etanercept, may reduce depressive symptoms in patients with psoriasis suffering from depression and in animal models of depression (Tyring et al., 2006, Krugel et al., 2012). In a randomised clinical trial, infliximab a TNF antagonist failed to separate from placebo, although an interaction between higher baseline TNF levels and greater reduction in depression scores with treatment was seen (Raison et al., 2013).
Depression has been linked with several atopic disorders within clinical and some population-based samples of individuals with asthma (Hurwitz and Morgenstern, 1999, Gunn et al., 2012, Afari et al., 2001, Loerbroks et al., 2012, Chun et al., 2008), eczema (Klokk et al., 2010, Yang et al., 2010), dermatitis (Hashiro and Okumura, 1997, Gunn et al., 2012) and allergic rhinitis (Cuffel et al., 1999, Hurwitz and Morgenstern, 1999, Marshall et al., 2002). These comorbidities appear to have an additive negative effect on functional status (Afari et al., 2001) and quality of life (Ford et al., 2003, Slattery et al., 2011, Lu et al., 2013, Goldney et al., 2003, Adams et al., 2004). Depression can compromise treatment adherence (Lehrer et al., 2002) and is thought to influence decision making in self-managed treatment (Adams et al., 2004) in patients with asthma.
Many of the previous studies investigating the relationship between depression and atopic disorders have been limited by an age range (Lu et al., 2013, Timonen et al., 2003, Hurwitz and Morgenstern, 1999, Klokk et al., 2010), restricted to clinical settings (Afari et al., 2001, Hashiro and Okumura, 1997), or reliant on self-report inventories to measure depression (Adams et al., 2004, Goldney et al., 2003, Marshall et al., 2002). The purpose of this study was to investigate whether an association exists between a lifetime diagnosis of allergic disorders and history of depression in a population-based sample of adult men and women, using a gold standard psychiatric measure and adjusting for potential confounders.
Section snippets
Participants
The Geelong Osteoporosis Study (GOS) (Pasco et al., 2012) is a prospective, cohort study comprising an age-stratified random sample of residents from the Barwon Statistical Division, recruited from the Commonwealth of Australia Electoral Rolls. Female participants were recruited between 1994 and 1997 and males between 2001 and 2006. For the purpose of this study, we utilized cross-sectional data collected at the 10-year follow up assessment for women and the 5-year assessment for men.
Of those
Results
Of the 2027 participants included in the analyses, 782 (38.6%) of participants had suffered from atopic disorders and 432 (21.3%) met criteria for a lifetime history of depression (MDD [n=383], minor depression [n=36] and dysthymia [n=13]). Participants with a past history of allergic diseases were older and more likely to be female (Table 1).
Allergic disorders were associated with a 73% increase in the likelihood of depression (unadjusted OR 1:73, 95% CI 1.40–2.15, p<0.001). Following
Discussion
In this cross-sectional population-based study, our results indicate increased likelihood of depression and MDD alone among men and women with allergic disorders. These associations were independent of socio-demographic characteristics, clinical and lifestyle factors.
These findings are concordant with studies conducted in the US; in a study of 6836 young adults (20–39 years) participating in the Third National Health and Nutrition Examination Survey (NHANES III), a lifetime diagnosis of asthma,
Role of funding source
The funding providers played no role in the design or conduct of the study; collection, management, analysis and interpretation of the data; or in preparation, review, or approval of the manuscript.
Conflict of interest
LS, ALS, MM, AO and PG have no conflicts of interest, including specific financial interests and relationships and affiliations relevant to the subject matter or materials discussed in the manuscript.
JAP has received speaker fees from Amgen, Eli Lilly and Sanofi–Aventis and funding from the Geelong Region Medical Research Foundation, Barwon Health, Perpetual Trustees, the Dairy Research and Development Corporation, The University of Melbourne, the Ronald Geoffrey Arnott Foundation, ANZ
Acknowledgments
The study was funded by the National Health and Medical Research Council (NHMRC) of Australia. The authors acknowledge the men and women who participated in the study.
References (57)
- et al.
The asthma/mental health nexus in a population-based sample of the United States
Chest
(2008) - et al.
Economic consequences of comorbid depression, anxiety, and allergic rhinitis
Psychosomatics
(1999) - et al.
A meta-analysis of cytokines in major depression
Biol. Psychiatry
(2010) - et al.
Self-reported asthma and health-related quality of life: findings from the behavioral risk factor surveillance system
Chest
(2003) - et al.
A role for Th1 and Th2 cells in the immunopathogenesis of atopic dermatitis
Immunol. Today
(1998) - et al.
Anxiety, depression and psychosomatic symptoms in patients with atopic dermatitis: comparison with normal controls and among groups of different degrees of severity
J. Dermatol. Sci.
(1997) - et al.
Regulatory T cells increased while IL-1beta decreased during antidepressant therapy
J. Psychiatr. Res.
(2010) - et al.
Revised nomenclature for allergy for global use: report of the nomenclature review committee of the World allergy organization
J. Allergy Clin. Immunol.
(2004) - et al.
Self-reports and general practitioner information on the presence of chronic diseases in community dwelling elderly. A study on the accuracy of patients' self-reports and on determinants of inaccuracy
J. Clin. Epidemiol.
(1996) - et al.
Altered expression of CD4(+)CD25(+) regulatory T cells and its 5-HT(1a) receptor in patients with major depression disorder
J. Affect Disord.
(2010)