Physical inactivity triples risk for depression in patients with lupus
Physical inactivity confers a “greater than threefold increased risk” for developing depression within the next 2 years among patients with systemic lupus erythematosus, according to data published in Arthritis Care & Research.
“Though the higher prevalence of depression in lupus relative to the general population is well demonstrated, the psychosocial, biological, and lifestyle factors responsible — and measures that can be taken to mitigate them — are not yet well-defined,” Sarah L. Patterson, MD, of the University of California, San Francisco, and colleagues wrote. “Prior studies to better understand risk factors for depression in lupus suggest that disease activity and treatment with glucocorticoids may play a role, but the link between depression and disease activity has been inconsistent across studies.”
“Moreover, indices of disease severity do not fully account for the relative burden of depression in this patient group,” they added. “Physical inactivity confers an increased risk of incident depression in the general population and may contribute to a higher incidence of mood disorders in SLE, but the link been inactivity and incident depression in this high-risk group has not been explored.”
To analyze physical activity as a predictor of depression among patients with SLE, Patterson and colleagues examined data from the California Lupus Epidemiology Study (CLUES), a longitudinal cohort of patients with confirmed SLE. Participants are assessed annually through telephone or in person, conducted in English, Spanish, Mandarin or Cantonese. For their own study, Patterson and colleagues analyzed data from 225 CLUES participants without baseline depression and who completed an in-person baseline assessment and at least one follow-up.
Physical inactivity was measured based on whether participants agreed with a single statement: “I rarely or never do any physical activities.” Depressive symptoms were assessed using the Patient Health Questionnaire (PHQ‐8), with incident depression defined as a PHQ‐8 of at least 10 at follow‐up. The researchers used Cox proportional hazard regression to model incident depression over 2 years, as a function of baseline physical inactivity. The model controlled for age, sex, race, income, comorbidities, disease activity and disease damage.
According to the researchers, mean PHQ scores for participants without baseline depression did not differ by activity status. However, participants who were inactive at baseline were significantly more likely to develop depression over the next two years (HR = 2.89; 95% CI, 1.46-5.71). This association remained strong after adjusting for covariates and included a greater than threefold increased risk for depression in sedentary participants (HR = 3.88; 95% CI, 1.67-9.03).
“This is the first study examining the association between physical inactivity and risk of incident depression in SLE,” Patterson told Healio Rheumatology. “After adjusting for potential confounding factors, physical inactivity conferred a greater than threefold increased risk of developing depression over 2 years of follow-up among a diverse lupus cohort. Physical inactivity was the strongest independent predictor of new onset depression, even more than poverty-level income, racial-ethnic minority status, SLE disease activity, coexisting cardiovascular disease or other comorbidities.”
“Interventions to support small increases in physical activity among SLE patients may reduce the disproportionate burden of depression experienced by this high-risk group,” she added. “Our findings highlight the importance of addressing lifestyle behaviors, and specifically physical activity practices, with our lupus patients during routine clinic visits. I am already using the findings from this study to counsel my patients about the important protective effects of physical activity, not only for cardiovascular disease prevention but also for reducing their risk of comorbid depression.”