There is a large body of evidence from all study design s which suggests that decreasing any type of sedentary time is associated with lower health risk in youth aged 5 - 17 years .
In particular , the evidence suggests that daily TV viewing in excess of 2 hours is associated with reduced physical and psychosocial health , and that lowering sedentary time leads to reductions in BMI
Accumulating evidence suggests that , independent of physical activity levels , sedentary behaviours are associated with increased risk of cardio-metabolic disease , all-cause mortality , and a variety of physiological and psychological problems .
Therefore , the purpose of this systematic review is to determine the relationship between sedentary behaviour and health indicators in school-aged children and youth aged 5 - 17 years .
Influence of diet, physical activity and parents’ obesity on children’s adiposity: a four-year longitudinal study
OBJECTIVE : To assess the relationships between diet , body composition , physical activity , parents ’ obesity and adiposity in children at the age of 8 y and four years later . STUDY DESIGN : Prospect i ve observational study of anthropometric measures initiated in 1992 , follow-up examination in 1996 . METHODS : 112 prepubertal ( age : 8.6±1.0 y ) children were studied .  Energy and nutrient intakes were assessed by diet history , body composition by anthropometry and physical activity , by a question naire . Obesity was defined as relative body mass index ( BMI ) ( rel BMI ) > 120 % , where rel BMI =( BMI / BMI at 50th centile for age and gender) × 100 . RESULTS : Prevalence of obesity was not statistically different at baseline ( 22.3 % ) than four years later ( 19.8 % ) : rel BMI at the age of 8 y was positively self-related with rel BMI at the age of 12 y ( r=0.73 , P<0.001 ) . After four years , eight ( 32 % ) obese children became non obese and five ( 6 % ) non obese children became obese . Multiple regression analysis ( stepwise procedure ) revealed that , in the final equation , the mother ’s BMI and TV viewing ( independent variables ) accounted for 17 % of the children ’s rel BMI variance at the age of 8 y ( R=0.42 , P<0.001 ) while the parents ’ BMI s accounted for 13.5 % of the children ’s rel BMI variance at the age of 12 y ( r=0.37 , P<0.001 ) . Other variables such as total energy intake , nutrient intake percentage and amount of physical activity , were all rejected . An autoregressive unbalanced measures model regression analysis recognised the mother ’s and father ’s BMI s as the only variables able to predict rel BMI in the children ( mother ’s BMI coeff . 2.53 ( s.e.m . 0.26 ) , P<0.0001 ; father ’s BMI coeff . 2.07 ( s.e.m . 0.23 ) , P<0.0001 ) . A multivariate logistic regression analysis was also performed . The children who participated in the follow-up , were divided into two groups based on the positive or negative change in the rel BMI between final and baseline measurements . Of all the variables considered , only rel BMI at baseline was selected in the final equation . Other variables such as age , gender , energy and nutrient intake , TV viewing and amount of physical activity  , as well as the parents ’ BMI , were all removed . CONCLUSIONS : The parents ’ obesity was the main risk factor for obesity in this group of children .  Sedentary behaviour ( TV viewing ) was independently associated with overweight at the age of 8 y. Physical activity and energy and nutrient intakes did not significantly affect the change in rel BMI over the four-year period when the parents ’ obesity was taken into account
There is a large body of evidence from all study design s which suggests that decreasing any type of sedentary time is associated with lower health risk in youth aged 5 - 17 years .
In particular , the evidence suggests that daily TV viewing in excess of 2 hours is associated with reduced physical and psychosocial health , and that lowering sedentary time leads to reductions in BMI
Accumulating evidence suggests that , independent of physical activity levels , sedentary behaviours are associated with increased risk of cardio-metabolic disease , all-cause mortality , and a variety of physiological and psychological problems .
Therefore , the purpose of this systematic review is to determine the relationship between sedentary behaviour and health indicators in school-aged children and youth aged 5 - 17 years .