Pictogram Is a Valid Instrument to Classify At-Risk Adult Population Based on Abdominal Obesity: Results from Pars Cohort Study

Abstract

Background: Abdominal obesity is associated with increased risk of myocardial infarction and death events. Thus, obtaining data on the status of abdominal obesity is important in risk factor assessment and prevention of non-communicable diseases. This study aimed to evaluate the validity of using pictograms to classify abdominal obesity indices (waist circumference [WC], waist-hip ratio [WHR], and waist-height ratio [WHtR]) into normal and at-risk categories and determine the effects of demographic characteristics on this validity. Methods: This cross-sectional study used data from Pars Cohort Study (PCS). Participants chose the most similar pictogram scores to their body size at 15, 30 years, and current age. Optimal normal/at-risk cut-off values for pictograms were calculated using sensitivity/specificity plots. Receiver operating characteristic curves were used to evaluate the validity of pictograms. Validity measures were analyzed across different subgroups of demographic characteristics. Results: A total of 9263 participants (46% males) were included in the study. The estimated area under the curves were 84% for WC, 77% for WHR, and 89% for WHtR in males, and 84% for WC, 73% for WHR, and 90% for WHtR in females. Optimal pictogram cutoffs to classify central obesity for WC, WHR, and WHtR were 4, 4, and 5 in males and 4, 4, and 6 in females, respectively. The majority of demographic characteristics were not associated with the validity of pictograms. Conclusion: Using pictograms to determine normal and at-risk categories of abdominal obesity indices is valid among adult population with a wide range of demographic characteristics. However, the results need to be interpreted with caution in those with a positive history of weight fluctuation.