Sex-specific association of peripheral blood cell indices and inflammatory markers with depressive symptoms in early adolescence.

Previous studies have reported the correlation of dysregulated blood cell indices and peripheral inflammatory markers with depression in adults but limited studies have examined this correlation in early adolescents. This study used data from the Chinese Early Adolescents Cohort Study, which was conducted in Anhui, China. Students' depression symptoms were repeatedly measured using the Chinese version of the Center for Epidemiological Studies Depression Scale for Children. Students' blood samples were collected in September 2019 and September 2021. The peripheral blood cell counts and inflammatory marker levels were determined using routine blood tests. Multivariable regression models were used to explore the associations between blood cell indices and adolescent depressive symptoms in both the whole sample and the sex-stratified samples. The white blood cell (WBC) count, neutrophil count (NC), platelet (PLT) count, neutrophil-to-lymphocyte ratio (NLR), platelet-to-lymphocyte ratio, and systemic immune inflammation index (SII) were positively correlated with the severity of depressive symptoms during follow-up. The mean corpuscular volume (MCV), mean hemoglobin (HGB) volume (MCH), and mean corpuscular HGB concentration (MCHC) exhibited negative temporal correlations with depressive symptoms. Additionally, several sex-specific blood cell markers were correlated with depression. Male adolescents with increased red blood cell (RBC) and female adolescents with decreased HGB levels and upregulated WBC, NC, NLR, and SII levels exhibited severe depressive symptoms at follow-up. These findings suggested the potential usefulness of peripheral blood cell indices in the assessment of depression in early adolescents. • Elevated WBC, NC, PLT, NLR, PLR, and SII were positively correlated with adolescent depressive symptoms. • Elevated MCH and MCHC were negatively correlated with adolescent depressive symptoms. • Boys with increased RBC exhibited severe depressive symptoms. • Girls with decreased HGB levels and upregulated WBC, NC, NLR, and SII levels exhibited severe depressive symptoms. • Our findings suggest the potential usefulness of peripheral blood cell indices in the assessment of adolescent depression. [ABSTRACT FROM AUTHOR]