© 2015 the Nordic Societies of Public Health DOI: 10.1177/1403494815581696 Scandinavian Journal of Public Health, 1–8 Introduction Body fat may act as ballast, hampering an athlete’s ability to overcome the resistance of gravity in move- ment, but adipose tissue is also a vital endocrine organ, in terms of health [1,2]. Failure to meet body composition goals among competitive athletes may result in career consequences, such as elimination from teams selected for competitions [3,4]; however, weight control and dieting behavior among young athletes can also lead to eating disorders and, in severe cases with persistent inadequate energy and nutrient intakes, to associated delayed pubertal development and retarded growth [5]. Inappropriate nutrition or unhealthy weight control practices can even result in acute and long-term medical complica- tions, such as osteoporosis and sudden death [6–9]. For prevention of malnutrition and eating disorders, sports clubs and federations need to be able to recog- nize individuals and groups of young athletes at risk [4,10–12]. In the present setting, primary prevention is defined as regulation, education and instruction designed to prevent overtraining, extreme dieting or eating disorders that could lead to unhealthy conse- quences in young athletes. The proportion of body fat (%BF) in athletes is known to vary, depending on the gender of the ath- lete and the sport [12]. In some sports with Body fat in children and adolescents participating in organized sports: Descriptive epidemiological study of 6048 Latvian athletes LIGA KALNINA 1,2 , MELITA SAUKA 1 , TOOMAS TIMPKA 3 , ÖRJAN DAHLSTRÖM 3 , EVA NYLANDER 4 , GUNTARS SELGA 1,5 , RENATE LIGERE 2 , HELENA KARKLINA 2 , ILGA S. PRIEDITE 1 & VIESTURS LARINS 6 1 State Sports Medicine Centre, Riga, Latvia, 2 Latvian University, Riga, Latvia, 3 Linköping University, Linköping, Sweden, 4 Department of Clinical Physiology, County Council of Östergötland, Linköping, Sweden, 5 Riga Stradins University, Riga, Latvia, and 6 Latvian Academy of Sports Education, Latvia Abstract Background: Pressure among young athletes to meet body composition goals may lead to poor nutrition and affect growth. Aims: To examine the proportion of body fat (%BF), measured by bioimpedance analysis, among Latvian children and adolescents participating in organized sports. Methods: Our study had a nationally representative sample of 6048 young athletes, aged 10–17 years. Their %BF was measured using a multifrequency, 8-pole, bioelectrical impedance leg-to-hand analyzer. Results: About 19.2% (CI 14.4–20.0) of boys and 15.1% (CI 14.0–16.3) of girls had a %BF value below the recommended levels. The %BF in young female athletes participating in aesthetic sports was lower than among their peers participating in other sports. Young male athletes participating in aesthetic sports had lower %BF levels at 10 and 12 years of age, compared with participants in weight-class sports; and lower levels of %BF from age 10–14 years, compared with participants in non-weight-sensitive sports. Conclusions: Almost every fifth child and adolescent participating in organized sports displayed critically low body fat levels. Body fat needs to be assessed regularly in young athletes, to prevent negative consequences on health. Key Words: Adolescents, aesthetic sports, body fat, body mass index, children, eating disorders, Latvia, percentage body fat, reference curves, sports, sport types, young athletes Correspondence: Melita Sauka, State Sports Medicine Centre, Riga, LV-1050, Latvia. E-mail: melita@latnet.lv (Accepted 19 March 2015) 581696SJP 0 0 10.1177/1403494815581696L. Kalnina et al.Body fat in young athletes research-article 2015 ORIGINAL ARTICLE