Summary
Background. Recently, body size related studies often use questionnaires and self-reported data not only to establish body image concerns, but for different analysis of body measurements. However, self-reported data depend on many individual (sex, age, actual body size, education, psychological status) and cultural factors (prevailing body image and societal perception of ideal body size). The aim of present study was to analyse the relationship between self-reported weight and height data in relation to measured (actual) weight and height in Lithuanian older adolescents with respect to age and sex.
Material and methods. In total 361 adolescents (119 boys and 242 girls) of 16-19 year of age from different Lithuanian towns were investigated. All participants filled in the questionnaire on their body size and body image concerns, and thereafter were measured by the specialists using the standard anthropometric methods. Data was processed usi ng standard statistical programmes Excel and SPPS 22.0.
Results. In all age groups, both girls and boys were tend to overestimate their height (p<0.001). Girls were more likely to underestimate their weight (p<0.001). Boys usually reported greater weight than actually measured weight (p<0.05). There were no statistically significant differences in self-reported body size discrepancies between different age groups, both in boys and in girls. The average BMI calcul ated from self-reported data was lower in comparison to the average of actual BMI. The preva lence of overweigh es ti mated ac cording to the actual body size was much higher (almost half of the cases in girls and almost one-third in boys respectively) in comparison to the calcul ated BMI from self-reported data. The prevalence of underweight estimated according to the actual body size was lower in girls (almost one-third) and higher in boys (about a quarter) in comparison to the calculated BMI from self-reported data. Normal weight girls were less likely to underestimate their weight than overweight girls (p<0.01), but more often underestimated their weight than underweight girls (p<0.01). The majority of underweight girls assumed their weight as normal one (p<0.05). In general, boys estimated their weight more precisely than girls.
Conclusion. The present findings demonstrated sex related discrepancy between self-reported and measured body size data that might lead to inaccurate estimation of the overweight (and underweight) prevalence. Self-reported values should not be used in monitoring body size changes at an individual, also population level.
Keywords: actual body size, self-reported weight, self-reported height, body image, sexual differences.
