Cross-sectional associations of asthma, hay fever, and other allergies with major depression and low-back pain among adults aged 20-39 years in the United States

Although low-back pain and depression are common comorbidities, the mechani sms responsible for their association remain unclear. The effects of proinf lammatory cytokines on the hypothalamic-pituitary-adrenal (HPA) axis lead t o the hypothesis that allergic reactions, as markers for inflammation-assoc iated activation of the HPA axis, result in aberrant responses to subsequen t stressors. Data from 6,836 US adults 20-39 years old from the Third Natio nal Health and Nutrition Examination Survey (1988-1994) were used. Subjects responded to questions regarding low-back pain in the past 12 months and h istory of asthma, hay fever, and other allergies. The history and onset of major depression were obtained from the Diagnostic Interview Schedule. Logi stic regression modeling was used to estimate the associations between alle rgies and depression and low-back pain. Subjects with a history of any alle rgy were more likely to report low-back pain (odds ratio = 1.51; 95% confid ence interval: 1.16, 1.96), to be diagnosed with major depression (odds rat io = 1.58; 95% confidence interval: 1.13, 2.21), and much more likely to ha ve both major depression and low-back pain (odds ratio = 3.03; 95% confiden ce interval: 1.32, 6.92). Hypersensitivity reactions may prime the HPA axis to respond aberrantly to stressors, resulting in physical and behavioral c onsequences.