Prolactin in obese children: a bridge between inflammation and metabolic-endocrine dysfunction

Adipocytes, regulated by insulin, represent the major peripheral source of prolactin (PRL), which play a pivotal role in energy balance, acting on adipogenesis and lipolysis. The aim of this study was to investigate whether PRL was associated with obesity-related inflammatory status and metabolic parameters. The diagnostic and prognostic role of PRL for metabolic syndrome (MS) was assessed. The effects of short-term lifestyle therapy on PRL levels were evaluated.

Prolactin was assessed in 94 obese patients and compared with 40 healthy children (HS).Patients were followed up for 1 year. Receiver operating characteristics (ROC) analysis was employed to find the best cut-off values capable of identifying MS in obese children for PRL, IL-6 and TNF-α. Kaplan-Meier curves were also generated. Adjusted risk estimates for MS were calculated using Cox proportional hazard regression analysis. An obesity intervention programme was administered for 12 months.

Prolactin levels were lower in obese patients than controls (P < 0·0001). PRL was found to be inversely correlated with BMI, IL-6 and HOMA-IR, whereas a direct correlation was found with HDL values. At ROC analysis, PRL showed higher sensitivity and specificity than IL-6 and TNF-α in identifying MS in obese children. Cox proportional hazard regression analysis showed that PRL predicted MS independently of other potential confounders. The lifestyle intervention improved PRL and metabolic parameters.

Prolactin represents a prognostic marker for obese children and a predictive factor for progression to MS. PRL measurement may be useful as part of the endocrine work-up of obese children.