Self-perceived body weight and weight status: analysis of concordance by age group and sex

Abstract

Objectives Previous studies suggest that there is discordance between actual weight status and body-weight perception. This fact has implications when it comes to designing public health interventions. The aim of this study was to estimate the prevalence of the different categories of weight status and body-weight perception and to analyse their concordance in a representative Spanish population sample.

Study design Cross-sectional study.

Methods Data were sourced from the 2018 Galician Risk Behaviour Data System, with the target population being all persons aged 16 years and above. We collected data on self-perceived body weight and assessed weight status on the basis of body mass index (BMI). BMI was estimated using self-reported measures of weight and height. To estimate concordance, Cohen's kappa coefficient, both unweighted and weighted with Cicchetti weights, was calculated.

Results Data were obtained for 7853 individuals aged 16 years and above, whereas the overall unweighted concordance was 0.393 (95%CI: 0.377–0.409), with an agreement percentage of 61.6%, weighted concordance was 0.503 (0.490–0.517), with an agreement percentage of 86.6%. The highest concordance between self-perceived body weight and weight status was observed in women. By age group, the highest concordance was observed in the youngest group (16–24 years) for the BMI categories of underweight and overweight, and in the 45–64 age group for the category of obesity.

Conclusions The results highlight the existence of differences between self-perceived body weight and weight status, according to sex and age