4 Effects of obesity on growth and puberty David B. Dunger * MD, FRCPCH Professor of Paediatrics M. Lynn Ahmed BSc, MPhil Research Assistant Ken K. Ong MRCPCH, PhD Lecturer Department of Paediatrics, University of Cambridge, Addenbrooke’s Hospital, Cambridge CB2 2QQ, UK Nutrition is an important regulator of the tempo of human growth. Infancy may represent a critical ‘window’ where variations in nutrition have longer-term consequences for growth and development. Rapid weight gain during infancy is associated with accelerated growth and early pubertal development. Rapid weight gain in infancy is also associated with the development of insulin resistance and an exaggerated adrenarche. Such circulating hormonal changes, together with elevated leptin levels and integral effects of fat cells on hormone action through local 11b- steroid dehydrogenase and aromatase activity could effect rate of progression of pubertal development in obese subjects. The secular trends in growth and maturation are partly attributed to changing nutrition. Recent data suggest that age at menarche may be static, but there is a debate as to whether the first signs of puberty are being seen much earlier in obese girls. Rapid early weight gain, obesity and early development may have implications for later health through the development of PCOS and overall association with cancer risk. Key words: obesity; growth; puberty; nutrition. Nutrition is an important regulator of the tempo of human growth, and obesity is usually associated with taller childhood stature and earlier pubertal development. In contrast, poor childhood nutrition delays the tempo of growth and pubertal onset. Although cross-sectional associations between childhood body weight and the timing of growth and development are seen, the tempo of growth may actually be set at a very early stage, during the perinatal period and infancy. Rapid weight gain during infancy Best Practice & Research Clinical Endocrinology & Metabolism Vol. 19, No. 3, pp. 375–390, 2005 doi:10.1016/j.beem.2005.04.005 available online at http://www.sciencedirect.com 1521-690X/$ - see front matter Q 2005 Elsevier Ltd. All rights reserved. * Corresponding author. Tel.: C44 1223 762944; Fax: C44 1223 336996. E-mail address: dbd25@cam.ac.uk (D.B. Dunger).