Fatness, Fitness and Physical Activity Among Young Icelanders: A Longitudinal Study

Aim To investigate eight-year changes in fatness, fitness and physical activity in a cohort of Icelandic children by comparing measurements conducted at two different time points.

Methods In 2003 a total of 489, 9-year-olds participated in a study called Lifestyle of 9 and 15 year-old Icelanders. A total of 258 from this cohort were recruited and measured again at the age of 17, in 2011. Measurements of body mass index (BMI; in kg/m²), waist circumferences (WC) and skinfold thicknesses were performed. Fitness (watts/kg) was also assessed with maximal cycle ergometer test and physical activity (PA) was measured with ActiGraph accelerometers.

Results Main findings show that on average BMI increased from 16.6 to 22.0 (n=258). Number of participants classified as overweight increased from 12.4% to 15.5% and obesity from 3.1% to 7.4% (n=258). Waist circumferences increased on average from 61.5 cm to 72.8 cm (n=258). Sum of 4 skinfolds increased on average from 34.0 mm to 49.2 mm (n=257). The average fitness score declined from 3.29 to 2.63 watts/kg (n= 122) and PA also declined on average from 492.313 to 242.021 counts/day (n=113).

Conclusions Mere few studies have been conducted in Iceland where the impact of lifestyle changes, such as fatness, fitness and physical activity from childhood to adolescents have been assessed. This is the first time that a longitudinal study is conducted to assess the development of health-related factors from childhood to adolescents in Iceland. Stronger understanding of the interplay between various determinants of health and well-being of children and adolescents is both valuable and important in future development and implementation of preventive measures.