24 In three of these studies, heights and weights were measured to preset standards by trained investigators,12 17 24 whereas heights and weights of our adolescent participants were mostly self-reported. It is possible that in our study some of the larger participants, www.selleckchem.com/products/Romidepsin-FK228.html particularly from body image conscious countries or cultures, may have under-reported their weights. In a study evaluating the correlation of measured versus self-reported heights and weights in adolescents, Brener et al found that their study subjects tended to over-report their height by 2.7 inches (6.9 cm) on average, and to under-report their weight by 3.5 pounds (1.6 kg) on average, resulting in a BMI understated by 2.6 kg/m2 when compared to measured values. White
adolescents were most likely to over-report their height and female adolescents were more likely to under-report their weight.25 Similarly, Danubio et al26 found that height was over-estimated in boys and girls (2.1 and 2.8 cm, respectively), and that weight was understated (1.5 kg in boys and 1.9 kg in girls). Rasmussen et al27 reported that in the COMPASS study, boys and girls who wished to be leaner under-reported their weight and BMI more than participants who were satisfied with their body size. When we restricted our analysis
to measured height and weight data only, the association between higher fast-food consumption and lower BMI was no longer observed in male adolescents, but the association between higher rates of fast-food consumption and lower BMI persisted in female adolescents. We need to consider the likelihood that, owing to the perception of the negative effects of fast-food consumption, adolescents
who are overweight or obese are likely to have under-reported their actual fast-food consumption. In a review of validation studies on energy intake reporting in children and adolescents, Livingstone and Robson found an increase in under-reporting of energy intake as age and BMI increased, with 14%, 25% and 40% of energy intake under-reported in obese 6-year-olds, 10-year-olds and adolescents, respectively.28 Finally, it is possible that our results are influenced by a degree of reverse causation where those participants who are already overweight or obese are avoiding fast-foods in order to reduce their body weight. Fast-food consumption This study has shown that up to 25% of children worldwide consume fast-food frequently or very frequently, and this increases to over 50% in the adolescent age group. This is consistent with results of Dacomitinib previous studies, particularly those based in the USA and the UK.11 29 30 This study has also highlighted the unexpectedly high proportion of fast-food consumption in both age groups in many developing countries, for which data have not previously been available. In particular, high prevalence of fast-food consumption was observed in centres in Latin America and Asia, which was similar in magnitude to that observed in the USA and Western Europe.