Sedentary behavior and metabolic risk factors in adolescents

Abstract

Background: This cross-sectional study was aimed at testing if self-reported sedentary behavior was associated with objectively measured bio-markers for metabolic risk factors in the participants of “Fit Futures – a part of the Tromsø Study”. Methods: All first year students in upper secondary school in the Tromsø region were invited to participate in the Fit Futures study in 2010-2011. 508 girls and 530 boys attended, giving an attendance rate of > 90 %. The present analysis included all participants aged 15-17 years with self-reported recreational physical activity and screen time (N=945). A Quest-Back based questionnaire on lifestyle, health and illness was filled out by the participants. Multivariate linear regression models were used to examine the associations of sedentary behavior and screen time with measured metabolic risk factors, including body mass index, waist circumference, waist-to-hip ratio (WHR), systolic and diastolic blood pressure, serum lipids, and glycated hemoglobin (HbA1c). Results: Sedentary adolescents had significantly higher average screen time than active students (34 versus 30 hours per week), and more smokers and snuff users (all P<0.01). Boys (20%) reported to be more sedentary than girls (11%). Sedentary behavior was associated with higher WHR and lower HDL(High-density lipoprotein)-cholesterol (both P<0.01) in the total population, and with higher WHR and lower HbA1c in girls (P<0.05). Screen time showed positive association with WHR and negative association with HDL-cholesterol in the total population and in girls alone, independent of physical activity (all P<0.05). Sedentary behavior was associated with higher WHR in the total population, and in addition, a negative association with HbA1c in girls (all P<0.05). There were no associations in boys. Conclusion: Sedentary behavior and screen time seem to be associated with abdominal obesity and lower levels of HDL-cholesterol among adolescents, and girls in particular. More detailed analysis of these cross-sectional data and prospective studies are needed.