Validity of Self-Reported Anthropometric Indices Used to Estimate Obesity in Greek Primary Schoolchildren

Abstract

The purpose of the present study was to assess the validity of self-reported height and weight as a screen tool for estimating overweight and obesity in primary schoolchildren. Self-reported and measured height and body mass were derived from 181 boys and 197 girls (mean age 11.4±0.4 yrs). The BMI cutoff points adopted by the International Obesity Task Force were utilized to compare prevalence estimates of overweight and obesity obtained from self-reported and actual measures. The results revealed that the students tended to overestimate their height (+0.59±3.4 cm, p<.002) and underreport their body mass (-1.53±3.6 kg, p<.0005). Thus, self-reported BMI was approximately 0.79±1.8 kg.m-2 lower than measured BMI (p<.0005). The degree of self-report bias in weight, height, and BMI did not differ between genders. Overweight and obese participants showed greater bias in self-reported weight than normal/underweight participants. Based on self-reports, prevalence estimates were 24.6% for overweight and 3.7% for obesity, but measured data showed significantly higher rates (overweight: 28.3%, obesity: 9.5%, χ2=277.66, p<.0005). The present
findings imply that self-reported anthropometric data obtained from Greek primary schoolchildren might not be valid and could lead to erroneous estimating rates of childhood overweight and obesity. This is of major importance, given that many large-scale epidemiological studies are based on self-reported data. The high prevalence rates of overweight and obesity observed in our sample offer some support on the reported growing obesity prevalence in Greek children, underlining the need for continuous monitoring of excess adiposity problems in childhood, using valid and accurate health surveillance tools.