Association between allostatic load and depression in patients with sleep disorders: Evidence from the National Health and Nutrition Examination Survey (NHANES).

Objective: Allostatic load (AL) is an indicator of the cumulative wear and tear on the body's physiological systems that can predict onset of a range of health problems. However, the relationship between AL and depression in patients with sleep disorders is unclear. This study explored the association between AL and depression in patients with sleep disorders.

Methods: Using data from the 2015-2016 National Health and Nutrition Examination Survey, a total of 4618 adults aged 18 years and older in the United States were included in this cross-sectional analysis. AL was calculated using nine biological markers, with a score of ≥3 indicating a high level. Depression was assessed using the Patient Health Questionnaire-9 (PHQ-9), with a score of ≥10 indicating risk for depression. Logistic regression models were employed to analyze the relationship between AL and depression.

Results: Among the 1309 participants diagnosed with sleep disorders, 212 (16.2%) were identified as being at risk for depression on the PHQ-9. A total of 55.2% (n = 117) of depressed persons had high AL levels. In the unadjusted model, AL levels were associated with depression in those with sleep disorders (OR=1.53, 95% CI = 1.14-2.05, p < 0.01). This relationship remained significant in the adjusted model (OR=1.52, 95% CI=1.11-2.10, p < 0.05), after controlling for potential confounders.

Conclusion: High AL levels in patients with sleep disorders were positively associated with depression, indicating that elevated AL may increase the risk of depression in this population, or alternatively, depression may increase the risk of AL.