Applied nutritional investigation The relationship between body composition and selected metabolic syndrome markers in black adolescents in South Africa: The PLAY study Annemarie Zeelie M.Sc. a , Sarah J. Moss Ph.D. a, * , Herculina S. Kruger Ph.D. b a Physical activity, Sport and Recreation in the School of Biokinetics, Recreation, and Sport Science, North-West University, Potchefstroom, South Africa b Centre for Excellence in Nutrition in the School of Physiology, Nutrition and Consumer Science, North-West University, Potchefstroom, South Africa. article info Article history: Received 2 September 2009 Accepted 4 March 2010 Keywords: Body composition Systolic blood pressure Insulin resistance Metabolic syndrome Adolescents abstract Objective: To determine the relationship between body composition and selected markers of the metabolic syndrome in black adolescents. Methods: The group consisted of 232 adolescent boys and girls aged 15–19 y attending two secondary schools in a low socio-economic status area of Potchefstroom, South Africa. Body mass (kg), stature (cm), and waist (WC) and hip circumferences were measured using standard methods. Body mass index and waist:hip ratio were calculated. Percentage body fat and lean body mass were measured by air displacement plethysmography. Fasting plasma insulin, fasting glucose, homeo- stasis model assessment of insulin resistance (HOMA-IR), systolic blood pressure (SBP), and dia- stolic blood pressure were measured. Results: Children with a high body fat percentage (boys >20%, girls >25%) had significantly higher serum leptin concentration than children with normal body fat percentage (boys, P ¼ 0.005; girls, P < 0.0001). Girls with a high body fat percentage also reported significantly higher SBP (P ¼ 0.004), diastolic blood pressure (P ¼ 0.03), plasma insulin (P ¼ 0.004), and HOMA-IR (P ¼ 0.004) than girls with normal body fat percentage. Body fat percentage had a significant positive association with HOMA-IR (P ¼ 0.02) and SBP (P ¼ 0.02), respectively. A significant positive correlation was also found between plasma leptin concentration and body mass index (P < 0.0001), WC (P < 0.0001), body fat percentage (P < 0.0001), and fat:height index (P < 0.001). Conclusion: A significant positive association was found between body fat percentage and both SBP and HOMA-IR, respectively. Girls with a high body fat percentage had significantly higher BP, plasma insulin, and HOMA-IR than girls with normal body fat percentage, indicating risk of non- communicable diseases. Ó 2010 Elsevier Inc. All rights reserved. Introduction The prevalence of obesity among adults and children in both developed and developing countries has reached epidemic proportions [1–3]. Of greatest concern is the fact that the increase in overweight and obesity is related to insulin resistance (HOMA-IR), hypertension, diabetes mellitus, dyslipidemia, coronary disease, and increased serum leptin levels [4–7]. Increases in the severity of obesity have also been shown to be related to the prevalence of the metabolic syndrome (MS) among children and adolescents [4]. Therefore, early identification of adolescents at risk of developing obesity is essential for the prevention of premature mortality [8]. Children in Africa are generally regarded to be predominantly underweight and the focus of recent research has been on undernutrition [9]. South Africa, however, has a low prevalence of underweight children (which may be due in part to the country’s positive economic growth) [10]. Indeed, the Youth Risk Behaviour Survey (n ¼ 9054), conducted in 2002, found that more than 17% of South African adolescents were overweight, and 4.2% were obese [11]. This trend is set to continue, based on the results of a regional school-based health and fitness survey of almost 5000 children aged 12–18 y. It is estimated that the future prevalence of obesity in 18-y-old girls will be 37% for black girls, 10% for white girls, and 20% for girls of mixed ancestry [10]. The factors that are causing this trend include sedentary behavior and passive overeating, as well as socio-cultural and economic influences and an obesogenic environment [3]. Even though this trend has been identified, studies designed to explore the relationship between body composition and * Corresponding author. Tel.: þ27 (0)18 299 1821; fax: þ27 (0)18 299 1821. E-mail address: Hanlie.Moss@nwu.ac.za (S. J. Moss). 0899-9007/$ – see front matter Ó 2010 Elsevier Inc. All rights reserved. doi:10.1016/j.nut.2010.03.001 Contents lists available at ScienceDirect Nutrition journal homepage: www.nutritionjrnl.com Nutrition 26 (2010) 1059–1064