Population-based references for waist and hip circumferences, waist-to-hip and waist-to-height ratios for children and adolescents, and evaluation of their predictive ability.

Childhood obesity is a public health problem globally as well as in Poland. This paper aimed to provide age- and sex-specific waist circumference, hip circumference, waist-to-height ratio and waist-to-hip ratio normative values for Polish children and adolescents aged 3 - 18 years for more precise monitoring of abdominal fat accumulation. The waist circumference, hip circumference, waist-to-height ratio and waist-to-hip ratio references were constructed with the lambda-mu-sigma (LMS) method using data from two nationally representative health surveys: the OLA study and the OLAF study, the largest available paediatric surveys in Poland which provided measured height, weight, waist, hip and blood pressure for 22,370 children and adolescents aged 3 - 18 years. The predictive ability of newly established references for overweight/obesity as defined by the International Obesity Task Force criteria and elevated blood pressure was tested with receiver operating characteristic. Abdominal obesity cut-offs linked to adult cardiometabolic cut-offs were established. Reference values for waist circumference, hip circumference, waist-to-height ratio and waist-to-hip ratio are presented, as well as waist circumference, waist-to-height ratio and waist-to-hip ratio cut-off values linked to adult's cut-offs of cardiometabolic risk. The predictive value for overweight and obesity of population-based waist, hip and waist-to-height ratio references was outstanding-area under the receiver operating characteristic curve > 0.95 in both sexes, whereas with regard to the elevated blood pressure predictive ability was low-area under the receiver operating characteristic curve < 0.65.   Conclusion: This paper presents the first waist, hip, waist-to-height ratio and waist-to-hip ratio references for Polish children and adolescents aged 3-18 years. The 90th and 95th percentile and cut-offs linked to adult thresholds for cardiometabolic risk are proposed as cut-offs for abdominal obesity. What is Known: • Waist circumference, waist-to-height ratio and waist-to-hip ratio are used to assess abdominal obesity in children and adults. • In Poland, there is no abdominal obesity and hip circumference references for children and adolescents from 3 to 18 years of age. What is New: • Population-based references of central obesity indices and hip references for children and youth aged 3-18 years and cardiometabolic risk thresholds for children and adolescents linked to adult's cut-offs were established.