Irisin and its relation to insulin resistance and puberty in obese children: a longitudinal analysis

J Clin Endocrinol Metab. 2015 May;100(5):2123-30. doi: 10.1210/jc.2015-1208. Epub 2015 Mar 17.

Abstract

Context: Irisin is a recently identified myokine affecting metabolic and glucose homeostasis. However, the role of irisin in obesity and its metabolic consequences are controversial, and data in children are scarce.

Objective: To study the relationships between irisin, insulin resistance, and puberty before and after weight loss in obese children with and without impaired glucose tolerance.

Design: One-year follow-up study in obese children participating in a lifestyle intervention.

Setting: Primary care.

Patients: Forty obese children and 20 normal-weight children of similar age, gender, and pubertal stage.

Intervention: A 1-year outpatient intervention program based on exercise, behavior, and nutrition therapy.

Main outcomes measures: Fasting serum irisin, weight status (body mass index [BMI] SD score), and the following parameters of the metabolic syndrome: insulin resistance index (homeostasis model of assessment), blood pressure, and lipids.

Results: The irisin levels were the highest in obese children with impaired glucose tolerance, followed by obese children with normal glucose tolerance, and levels were lowest in normal-weight children (P < .001). In a multiple linear regression analysis, baseline irisin was significantly associated with pubertal stage, high-density lipoprotein-cholesterol, and homeostasis model of assessment, but not to age, gender, BMI, or any other parameter of the metabolic syndrome. The irisin concentrations were significantly (P = .010) lower in the prepubertal compared to the pubertal children. In longitudinal analyses, changes of irisin were significantly associated with entry into puberty, change of fasting glucose, and 2-hour glucose in an oral glucose tolerance test, but not with change of BMI or any other parameter.

Conclusions: Irisin levels are related to pubertal stage and insulin resistance but not to weight status in childhood.

Trial registration: ClinicalTrials.gov NCT00435734.

MeSH terms

  • Adolescent
  • Blood Glucose / metabolism
  • Blood Pressure / physiology
  • Body Mass Index
  • Child
  • Female
  • Fibronectins / blood*
  • Follow-Up Studies
  • Glucose Tolerance Test
  • Humans
  • Insulin / blood
  • Insulin Resistance / physiology*
  • Longitudinal Studies
  • Male
  • Obesity / blood
  • Obesity / metabolism*
  • Obesity / therapy
  • Puberty / blood*
  • Weight Loss / physiology*

Substances

  • Blood Glucose
  • FNDC5 protein, human
  • Fibronectins
  • Insulin

Associated data

  • ClinicalTrials.gov/NCT00435734