medwireNews: Women with a history of depression are more than twice as likely as those without depression to develop systemic lupus erythematosus (SLE), shows an analysis of data from the Nurses’ Health Study.
The study included 194,483 women who were followed up for 20 years. During this time, 145 women developed SLE, as indicated by the presence of four or more ACR 1997 classification criteria.
Approximately a quarter of the women had a history of depression, defined as regular antidepressant use, a clinician’s diagnosis, or a score below 60 on the 5-item mental health inventory (MHI-5). These women had a significant 2.67-fold increased risk for developing SLE during follow-up compared with those who did not have depression.
Furthermore, the increased risk was only slightly attenuated, to 2.45-fold, when BMI, cigarette smoking, oral contraceptive use, and postmenopausal hormone use were taken into account.
The researchers found that SLE occurred a median 4.5 years after depression was recorded, but to check that the associations were not due to SLE causing depression or depression being an early symptom of SLE they conducted a number of sensitivity analyses.
These showed that depression continued to be associated with an increased risk for developing SLE when depression status was lagged by 4 years (hazard ratio [HR]=1.99) and when depression status at baseline only was considered (HR=2.28).
The definition of depression affected the strength of the association with SLE, with the strongest relationship observed when antidepressant use was used as the indicator (HR=2.80). There was a slightly weaker association with a clinician’s diagnosis of depression (HR=2.19), and it was weaker still when the MHI-5 score was used to define depression (HR=1.70).
Andrea Roberts (Harvard TH Chan School of Public Health, Boston, Massachusetts, USA) and study co-authors say that the weakened association with MHI-5 score could be because this variable was assessed less often than antidepressant use and depression diagnosis during follow-up or because there may be a dose–response association between SLE and depressive symptoms.
They say: “[W]omen with depressive symptoms as defined when based on the use of a screening tool [may not be] as severely depressed as those who receive a depression diagnosis or antidepressant medication.”
Writing in JAMA Psychiatry, Roberts et al conclude: “Our study contributes to increasing evidence that depression may constitute a causal risk factor for autoimmune disease. Screening of patients with depression for family history and symptoms of SLE may improve its early detection.
“In addition, lifestyle interventions to reduce inflammation in persons with depression may reduce risk of autoimmune disease as well as other negative health sequelae of depression, including cardiovascular disease.”
By Laura Cowen
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