Abstract
AIMS: Individuals with prior depressive episodes have a more fragile homeostasis, but the exploration of depression recurrence remains limited. Our study aimed to explore the associations of allostatic load (AL) and frailty with the risk of depression recurrence.</p>
METHODS: This study included 9,936 individuals from the UK Biobank who reported depression prior to recruitment. AL and frailty were estimated based on 10 biomarkers and 5 indicators, respectively. The outcome was recurrence of depression, determined by International Classification of Diseases (ICD-10) codes based on self-report, inpatient hospital data, primary care, and death records. Cox proportional hazards models were used to assess the prospective association of AL and frailty with the risk for recurrence of depression, and stratified analyses were conducted by gender, age, and Townsend deprivation index (TDI). Additionally, the mediating effect of either AL or frailty on the association of the other with the recurrence of depression was examined.</p>
RESULTS: During a median follow-up of 13.19 years, 1,864 individuals with depression experienced recurrence of depression. Compared to those with low AL, individuals with medium (HR: 1.25; 95% CI: 1.11-1.41) and high AL (HR: 1.42; 95% CI: 1.26-1.60) had an increased risk of depression recurrence. Compared to nonfrail individuals, those with prefrailty (HR: 1.43; 95% CI: 1.28-1.59) and frailty (HR: 1.72; 95% CI: 1.48-1.99) had an increased risk of depression recurrence. The stronger effects were observed in women and middle-aged groups. Bidirectional mediation analyses revealed that frailty mediated 22.42% of allostatic load's effect on recurrence risk, while AL mediated 12.27% of frailty's effect.</p>
CONCLUSION: Assessing AL and frailty may help identify individuals at high risk of depression recurrence, with their simultaneous management potentially mitigating this risk.</p>