[Accuracy of body mass index derived from self-reported height and weight in a spanish sample of children].

Introduction: In the children obesity research field, weighing and measuring involves high research costs, which could be reduced if the self-reported body mass index (BMI) was ascertained to be a valid index.

Objective: To analyze the accuracy of children's selfreported BMI.

Materials And Methods: 171 school students from Madrid participated in the study (Mean age: 10,68 years). They were weighed and measured, and were also asked to report their weight and height. Both current and selfreported BMI were calculated.

Results: The correlation between self-reported BMI and the current BMI was r = .803 (p < .001), and the kappa indexex ranged from k = .38 to .46.

Conclusions: The self-reported BMI noticeably coincide with the current BMI in 10 to 11 year-old children. However, a modest concordance was found between the categorization within a weight-related group (normal, overweight and obese) based on both indexes, which shows the former could be a valid measure when carrying out population studies on obesity and overweight.