Resumen de Inflammatory Cytokine Levels and Depressive Symptoms in Older Women in the Year After Hip Fracture:: Findings from the Baltimore Hip Studies
Maya E. Matheny, Ram R. Miller, Michelle Shardell, William G. Hawkes, Eric J. Lenze, Jay Magaziner, Denise Orwig
Objectives: To determine whether interleukin (IL)-6 or soluble tumor necrosis factor alpha receptor 1 (sTNF-?R1) is associated with depressive symptoms in the year after hip fracture.
Design: Prospective cohort.
Setting: Three Baltimore-area hospitals.
Participants: Community-dwelling women aged 65 and older admitted with a new, nonpathological fracture of the proximal femur (N = 134).
Measurements: Two, 6, and 12 months after fracture, serum was analyzed for IL-6 and sTNF-?R1, and depressive symptoms were measured using the 15-item Geriatric Depression Scale (GDS). Generalized estimating equations were used to model the longitudinal relationship between IL-6, sTNF-?R1, and GDS score. Whether lower extremity function, as measured according to the Lower Extremity Gain Scale (LEGS), explained the relationship between IL-6, sTNF-?R1, and GDS score was also examined.
Results: Participants in the highest categories of IL-6 (?5.14 pg/mL) and sTNF-?R1 (?2,421 pg/mL) had the highest GDS scores in the year after fracture (P = .09 for both). Twelve months after fracture, those in the highest IL-6 and sTNF-?R1 categories had GDS scores that were on average 1.9 (95% confidence interval (CI) = 0.4�3.4, P = .01) and 1.4 (95% CI = -0.1�3.0, P = .07) points higher than those in the lowest category, respectively. Adjusting for LEGS score, the mean difference in GDS scores for highest versus lowest IL-6 categories was 1.6 (95% CI = 0.2�3.0, P = .02) points at 12 months.
Conclusion: Results from these exploratory analyses support a role for inflammation in the pathophysiology of depressive symptoms after hip fracture. Depressive symptoms in the context of high cytokine levels may represent a sickness syndrome that is chronic in some individuals. Further research should establish the cause and effect of this relationship, as well as long-term correlates.
