Prevention of overweight/obesity in children and youth

Assessing Strength or Quality of the Evidence The strength of the evidence was determined based on the GRADE system of rating the quality 57,58 of evidence. [...] The GRADE system rates the quality of a body of evidence as high, moderate, low or very low; each of the four levels reflects a different assessment of the likelihood that further research will impact the estimate of effect (i.e., high quality: further research is unlikely to change confidence in the estimate of effect; moderate quality: further research is likely to have an important impact on co [...] A GRADE quality rating is based on an assessment of five conditions: (1) risk of bias (limitations in study designs), (2) inconsistency (heterogeneity) in the direction and/or size of the estimates of effect, (3) indirectness of the body of evidence to the populations, interventions, comparators and/or outcomes of interest, (4) imprecision of results (few participants/events/observations, wide con [...] The DerSimonian and Laird random effects model with inverse variance (IV) method was utilized to generate the summary measures of effect in the form of standardized mean difference (SMD) for the primary weight outcome of change in BMI/BMIz and mean 60 difference (MD) for other continous outcomes. [...] However, at the request of the CTFPHC, we used four decimals in our calculations and in the presentation of results in the Evidence Sets.