Obesity is associated with acute inflammation in a sample of adolescents.

BACKGROUND: Obesity is associated with a mild chronic inflammatory response, which has been suggested to be pivotal in the development of cardiometabolic alterations of obesity. However, little is known about the involvement of acute inflammation.
OBJECTIVE: To evaluate whether circulating neutrophils, markers of acute inflammation, are associated (quantitatively and qualitatively) with adolescent obesity and whether leptin modulates these associations. SUBJECTS AND METHODS: We assessed 528 adolescents (16.8 yr old, 47% females), without chronic/acute illness. We measured anthropometry and dual energy X-ray absorptiometry and calculated fat mass percentage (FM%). Fasting serum glucose, high-density lipoprotein (HDL)-cholesterol, and triglycerides were used with blood pressure and waist circumference to compute a metabolic z-score. Leukocyte and neutrophil counts were obtained, together with levels of serum leptin. In a subsample of 23 males, flow cytometry was used to assess degranulation (CD66b expression) of neutrophils.
RESULTS: Female sex and obesity were positively related to mean neutrophil counts (p < 0.05). When accounting for sex and weight status, leptin was associated with neutrophil counts (p < 0.05), partially explaining the association between obesity and neutrophil counts. Neutrophil counts were related to metabolic risk z-scores, controlling for fat mass. Participants with elevated FM% showed more neutrophil degranulation than controls (p < 0.05).
CONCLUSIONS: Participants with increased adiposity had higher circulating neutrophil counts, suggesting acute inflammation. Furthermore, the neutrophils showed more degranulation, indicating inflammation. Obesity-induced alteration of the adipose secretory pattern (i.e., changes in leptin levels) could be involved in acute inflammation.