Association of peripheral inflammatory cell counts with depression among cancer survivors: a cross-sectional study based on the NHANES dataset.

[BACKGROUND] Depression occur more frequently in cancer patients than in the general population. However, the association between inflammatory biomarkers and depression in cancer survivors is not well understood. This study aimed to examine the correlation between inflammatory biomarkers and depression in patients with solid tumors and to identify clinical and biological factors related to this association.

[METHODS] The cross-sectional cohort study analyzed data from the National Health and Nutrition Examination Survey (NHANES) 2005-2018, including 2,926 cancer survivors aged 20 years and older. Depression was assessed using the Patient Health Questionnaire-9 (PHQ-9), and inflammatory biomarkers were derived from blood count measurements. Prevalence and regression analyses were conducted to evaluate the associations between inflammatory biomarkers and depression in patients with solid tumors, and the robustness of the models was assessed through sensitivity analyses.

[RESULT] Among the 2,926 cancer survivors, 25.80% exhibited depression, including mild (15.52%), moderate (8.95%), and severe (1.33%) cases. Patients with digestive system cancers (OR = 1.63, 95% CI: 1.18-2.24, P = 0.003) and those with reproductive system cancers (OR = 1.47, 95% CI: 1.12-1.93, P = 0.005) were significantly associated with a higher prevalence of depression. Further subgroup analysis revealed that, in colorectal cancer patients, female (OR = 2.33, 95% CI [1.15-4.74], P = 0.020), neutrophil (NE) counts above 6.4 (OR = 4.02, 95% CI [1.36-11.90], P = 0.012) and monocyte (MO) counts above 0.8 (OR = 3.21, 95% CI [1.03-10.00], P = 0.045) were positively associated with depression, whereas age under 45 years (OR = 1.826, 95% CI [1.073-3.106], P = 0.026) was associated with depression in patients with uterine tumors. In addition, sensibility analysis conducted in the subgroup of colorectal cancer patients with mild depressive symptoms indicated that the observed associations were robust.

[CONCLUSION] Depression is common among cancer survivors, particularly in those with digestive and reproductive system cancers. In colorectal cancer patients, female sex and elevated neutrophil and monocyte counts were associated with higher prevalence of depression, while younger age was associated with depression in uterine cancer patients. These findings highlight the potential relevance of inflammatory biomarkers in understanding depression among cancer survivors. Future longitudinal studies are warranted to further explore the temporal and biological relationships underlying these associations.