Supplementary Material for: Parental Perceptions of Children’s Weight Status in 22 Countries: The WHO European Childhood Obesity Surveillance Initiative: COSI 2015/2017

Introduction: Parents can act as important agents of change and support for healthy childhood growth and development. Studies have found that parents may not be able to accurately perceive their child’s weight status. The purpose of this study was to measure parental perceptions of their child’s weight status and to identify predictors of potential parental misperceptions. Methods: We used data from the World Health Organization (WHO) European Childhood Obesity Surveillance Initiative and 22 countries. Parents were asked to identify their perceptions of their children’s weight status as “underweight,” “normal weight,” “a little overweight,” or “extremely overweight.” We categorized children’s (6–9 years; n = 124,296) body mass index (BMI) as BMI-for-age Z-scores based on the 2007 WHO-recommended growth references. For each country included in the analysis and pooled estimates (country level), we calculated the distribution of children according to the WHO weight status classification, distribution by parental perception of child’s weight status, percentages of accurate, overestimating, or underestimating perceptions, misclassification levels, and predictors of parental misperceptions using a multilevel logistic regression analysis that included only children with overweight ( including obesity). Statistical analyses were performed using Stata version 15 1. Results: Overall, 64.1% of parents categorized their child’s weight status accurately relative to the WHO growth charts. However, parents were more likely to underestimate their child’s weight if the child had overweight (82.3%) or obesity (93.8%). Parents were more likely to underestimate their child’s weight if the child was male (adjusted OR [adjOR]: 1.41; 95% confidence intervals [CI]: 1.28–1.55); the parent had a lower educational level (adjOR: 1.41; 95% CI: 1.26–1.57); the father was asked rather than the mother (adjOR: 1.14; 95% CI: 0.98–1.33); and the family lived in a rural area (adjOR: 1.10; 95% CI: 0.99–1.24). Overall, parents’ BMI was not strongly ...