Original article Autonomic nervous system functions in obese children Cengiz Yakinci a, * , Bu Èlent Mungen b , Hamza Karabiber a , Meltem Tayfun a , Cem Evereklioglu c a Department of Pediatrics, Ino Ènu È University Medical School, Malatya, Turkey b Department of Neurology, Fõrat University Medical School, Elazõg, Turkey c Department of Ophthalmology, Ino Ènu È University Medical School, Malatya, Turkey Received 20 August 1999; received in revised form 15 December 1999; accepted 7 January 2000 Abstract Childhood obesity is a complex syndrome, probably due to the multiplicity of contributing factors, contradictory literature information about etiology, prognosis, prevention and treatment. In the recent reports, autonomic nervous system (ANS) dysfunction has been docu- mented in adult obesity. Autonomic nervous system functions in obese children are not clear. This study was planned to investigate autonomic nervous system function in childhood (7±13 years of age) obesity. Study and control groups consisted of 33 simple obese (23 boys and ten girls, mean age 9.5 ^ 1.4 years) and 30 healthy children (18 boys and 12 girls, mean age 10.1 ^ 1.8 years), respectively. Four non-invasive autonomic nervous system function tests (Orthostatic test, Valsalva ratio, 30/15 ratio, Heart rate responses to deep breathing) and general ophthalmic examination were performed on both groups. The difference between the obese and control groups was found statistically signi®cant in Valsalva ratio, 30/15 ratio and Heart rate responses to deep breathing (P , 0:025), and insigni®cant in Orthostatic test (P . 0:05). Ophthalmic examinations were normal. The result of these tests suggested normal activity of sympathetic, and hypoactivity of parasympathetic nervous system, implying parasympathetic nervous system dysfunction as a risk factor or associated ®nding in childhood obesity. q 2000 Elsevier Science B.V. All rights reserved. Keywords: Autonomic nervous system; Obesity; Childhood 1. Introduction Obesity is characterized by an excessive deposition and storage of fat. Simple obesity of infancy and childhood is a complex syndrome that is the ®nal common pathway of the interplay of multiple factors, including genetics, prenatal experience, familial and cultural practices, emotional factors, and activity levels [1,2,4,5]. In recent literature, autonomic nervous system (ANS) dysfunction has been reported in adult obesity [4±9]. The relationship between obesity and ANS function has not been cleared yet. Studies about ANS function in childhood obesity are limited. This study was planned to investigate ANS functions in child- hood obesity. 2. Materials and methods This study was performed on 33 obese (23 boys and ten girls; mean age 9.5 ^ 1.4 years) and 30 healthy (18 boys and 12 girls; mean age 10.1 ^ 1.8 years) children aged 7±13 years. The difference for ages in two groups was not signif- icant (P . 0:05). The body mass index (BMI) was over 120% in the obese group (OG) and under 100% in control group (CG). Simple obesity was de®ned as normal physical examination, normal height for age and normal bone age. After obtaining written consents, the following four non- invasive autonomic nervous system function tests and general ophthalmic examination including visual acuity were performed on every child [3]. All studies were performed in an outpatient clinic in the morning. All four tests of a subject were done on the same day. After every test, children were allowed to rest for 2 min unless stated otherwise. All tests (with the exception of the orthostatic test) were performed with the subject in the supine position. Blood pressure measurements were done by automatic sphygomanometer. 2.1. Test 1: Orthostatic test Blood pressures (BP) were recorded with a proper arm sphygomanometer in supine position and while standing up after 15 min of resting. BP was recorded just before and immediately after standing up as well as during standing at 1 min intervals. After a 5 min rest in the supine posture, the whole procedure was repeated. The higher orthostatic Brain & Development 22 (2000) 151±153 0387-7604/00/$ - see front matter q 2000 Elsevier Science B.V. All rights reserved. PII: S0387-7604(00)00094-2 www.elsevier.com/locate/braindev * Corresponding author. Yakõncõ Eczanesi, 44300, Malatya, Turkey. Tel.: 190-422-325-4000; fax: 190-422-341-0728.