Strengths of our study include the population-based and
multidisciplinary approach. Other strengths include measurements
of participants’ height and weight, the adjustment
for nonresponse bias and the consideration of various
potential confounders. Although most of the questions and
questionnaires we administered were validated, responses
remain subjective and prone to error. An additional limitation
is the cross-sectional design, which introduces uncertainties
regarding the sequence of cause and effect of the
observed associations. Longitudinal studies overcome this
limitation and will strengthen the evidence regarding risk
factors for childhood overweight and obesity.
In summary, we have shown that school- and familybased
factors are associated with an increased risk of childhood
overweight and obesity, and therefore they present
opportunities for targeting this problem. Recommendations
for action include more physical education classes and
promotion of healthy lunches at schools and of family suppers
at home. Preventive public health actions should be
targeted first toward low-income neighbourhoods.