In two new Cochrane Reviews the effect of diet, physical activity and behavioural interventions for the treatment of overweight have been assessed among children (6-11 year) and adolescents (12-17 year). The researchers concluded that multidisciplinary interventions are beneficial in achieving positive effect on BMI and weight in overweight children and adolescents. Especially in children more insights are needed on the long-term effects.
The number of overweight children and adolescents is increasing worldwide. Interventions to treat overweight children and adolescents often include multiple lifestyle factors such as diet, physical activity and behavioural factors. Two new Cochrane Reviews examined the effect of those interventions among children (6-11 year) and adolescents (12-17 year). The present Cochrane review is an update of an earlier review first published in 2003 and then updated in 2009.
The authors searched different databases including CENTRAL and MEDLINE for Randomised Controlled Trials (RCTs) that examined the effect of diet, physical activity and behavioural change interventions on overweight children and adolescents. The researchers had two additional criteria for the interventions among children: the follow-up period needed to be at least 6 months and interventions that were meant to treat other diseases such as type 2 Diabetes were excluded.
The review among children aged 6-11 years examined the results of 70 interventions conducted in 8461 overweight children in Europe, Malaysia, Japan, Canada, New-Zealand, Australia and the USA.
- The average age of the children was 10 years. Most studies reported the BMI z score, which is the BMI value which takes into account gender, age, weight and height changes.
- The BMI z score was on average 0.06 units lower in the intervention group compared with the controls (37 studies; 4019 children).
- BMI was on average 0.53 kg/m2 lower in the intervention group compared with the control groups (24 studies; 2785 children).
The review among adolescents aged 12-17 years examined the results of 28 interventions conducted in 4781 overweight adolescents.
- The average age of the adolescents ranged from 12-17.5 years. Most studies reported BMI values.
- BMI was on average 1.18 kg/m2 lower in the intervention group compared with the control groups (28 studies; 2774 adolescents).
- Body weight was on average 3.67 kilogram lower in the intervention group compared with the control groups (20 studies; 1993 adolescents).
- In the follow-up period of 18-24 months the BMI reduction was maintained and was on average 1.49 kg/m2 lower than the control groups.
Multidisciplinary interventions that focus on lifestyle factors like diet, physical activity and behavioural interventions may be beneficial in achieving (small) positive effects on BMI. The interventions can promote a healthy weight in children and adolescents, mainly when the results are compared with controls who received no treatment or who were on the waiting list. However, the researchers found that the evidence is low to moderate, since the studies in the review were inconsistent in the measurement of physical activity, dietary intake and dietary behaviours. According to the researchers, the evidence should therefore be interpreted with caution. Especially in the younger age group (6-11 year) the long-term effects of the interventions need to be considered and there is need for long-term follow-up to examine the effect of the intervention on BMI and weight over a longer period.
- Mead, M. et al (2017). Diet, physical activity and behavioural interventions for the treatment of overweight or obese children from the age of 6 to 11 years. DOI: 10.1002/14651858.CD012651 http://onlinelibrary.wiley.com/doi/10.1002/14651858.CD012651/full
- Al-Khudairy, L. et al (2017). Diet, physical activity and behavioural interventions for the treatment of overweight or obese adolescents aged 12 to 17 years. DOI:10.1002/14651858.CD012691. http://onlinelibrary.wiley.com/doi/10.1002/14651858.CD012691/full