Cardiovascular risk factor clustering and its association with fitness in nine-year-old rural Norwegian children G. K. Resaland 1,2 , A. Mamen 1 , C. Boreham 3 , S. A. Anderssen 2 , L. B. Andersen 2 1 Faculty of Teacher Education and Sport, Sogn og Fjordane University College, Sogndal, Norway, 2 Norwegian School of Sport Sciences, Department of Sports Medicine, Oslo, Norway, 3 Institute for Sport and Health, University College Dublin, Dublin, Ireland Corresponding author: Geir Ka ˚re Resaland, Faculty of Teacher Education and Sport, Sogn og Fjordane University College, PO Box 133, N-6851 Sogndal, Norway. Tel: 1474 162 1333 or 1475 767 6097, Fax: 1475 767 6333, E-mail: geirkr@hisf.no Accepted for publication 4 January 2009 This paper describes cardiovascular disease (CVD) risk factor levels in a population-representative sample of healthy, rural Norwegian children and examines the asso- ciation between fitness and clustering of CVD risk factors. Final analyses included 111 boys and 116 girls (mean age 9.3  0.3). To determine the degree of clustering, six CVD risk factors were selected: homeostasis model assessment score, waist circumference, triglycerides, systolic blood pressure, total cholesterol to high-density lipoprotein ratio and fitness (VO 2peak ). Clustering was observed in 9.9% of the boys and 13.8% of the girls. In a different analysis, fitness was omitted as a CVD risk factor and analyzed against the five remaining CVD risk factors. Low fitness was a strong predictor for clustering of CVD risk factors, and children in the least-fit quartile had significantly poorer CVD risk factor values than all of those in the other quartiles. Finally, subjects were cross-tabulated into different fat–fit groups. For both sexes, the unfit and overweight/obese group had a significantly higher CVD risk factor score than the fit and normal weight group. Cluster- ing of CVD risk factors was present in this group of rural children. Low fitness, and low fitness and high fatness combined, were highly associated with a clustered CVD risk. The clustering of atherosclerotic cardiovascular dis- ease (CVD) risk factors, often referred to as the metabolic syndrome, increases the risk of both CVD and type 2 diabetes in adults (Wilson et al., 2005). Although the clinical endpoints for CVD are almost non-existent in children, precursors of atherosclerosis, known as fatty streaks, do develop in children (Be- renson et al., 1998). Additionally, CVD risk factors have been shown to cluster in children as young as nine (Andersen et al., 2003). Furthermore, this sort of clustered risk often tracks from childhood to adult- hood (Twisk et al., 1997; Raitakari et al., 2003), creating a lifetime of exposure to and an elevated risk of CVD. From a public health perspective, it is particularly important to identify children with a clustered risk at the earliest opportunity so that primary preventive strategies can be put in place to prevent later onset of disease. In Norway, data on children’s CVD risk factors are sparse, and the little data available on children’s CVD risk factor profiles are mainly from urban Oslo. However, many children live in rural settings, and so it is important to gather data on these children, particularly as their lifestyles may differ from those of their urban counterparts. Recently, it was shown that low cardiorespiratory fitness (fitness) is a strong predictor for clustering of CVD risk factors (Anderssen et al., 2007), and that fitness and physical activity are separately and in- dependently associated with clustered metabolic risk in children (Ekelund et al., 2007). Additionally, it was shown that high fitness is associated with a healthier cardiovascular profile (Brage et al., 2004; Ruiz et al., 2007). Still, limited research exists on 9- year-old children, and therefore the association be- tween fitness and clustering of CVD risk factors remains uncertain. This paper, therefore, has two main aims. Firstly, it seeks to describe the CVD risk factor levels for a population-representative sample of 9-year-old, ap- parently healthy, rural Norwegian children and sec- ondly, to examine the association between fitness and clustering of CVD risk factors. Materials and methods The participants were part of a school-based physical activity intervention study, and the presented data are baseline data. The sample included all fourth graders (age 9.3  0.3, n 5 259) in two consecutive years (born in 1995–1996) in two rural elementary schools in Sogn og Fjordane County, western Norway. The communities, Sogndal (population 6836) 1 and 1 According to Statistics Norway on January 1, 2006. Scand J Med Sci Sports 2009 & 2009 John Wiley & Sons A/S Printed in Singapore . All rights reserved DOI: 10.1111/j.1600-0838.2009.00921.x 1