Abstract: Background: Waist circumference (WC) is commonly measured by either the World Health Organization (WHO) or National Health and Nutrition Examination Survey (NHANES) protocol.

Objective: Compare the associations of WHO vs. NHANES WC-to-height ratio (WHtR) protocols with cardiometabolic risk factors (CMRFs) in a sample of youth with diabetes.

Methods: For youth (10–19 years old with type 1 [N=3082] or type 2 [N=533] diabetes) in the SEARCH for Diabetes in Youth Study, measurements were obtained of WC (by two protocols), weight, height, fasting lipids (total cholesterol, triglycerides, HDL cholesterol, Non-HDL cholesterol) and blood pressures. Associations of CMRFs with WHO and NHANES WHtR were modeled stratified by body mass index (BMI) percentiles for age/sex: lower BMI (<85^th BMI percentile; N=2071) vs. higher BMI (≥85^th percentile; N=1594).

Results: Among lower-BMI participants, both NHANES and WHO WHtR were associated (p<0.005) with all CMRFs except blood pressure. Among higher-BMI participants, both NHANES and WHO WHtR were associated (p<0.05) with all CMRFs. WHO WHtR was more strongly associated (p<0.05) than NHANES WHtR with triglycerides, non-HDL cholesterol, and systolic blood pressure in lower-BMI participants. Among high-BMI participants, WHO WHtR was more strongly associated (p<0.05) than NHANES WHtR with triglycerides and systolic blood pressure.

Conclusion: Among youth with diabetes, WHtR calculated from either WC protocol captures cardiometabolic risk. The WHO WC protocol may be preferable to NHANES WC.

Keywords: Waist Circumference, Body Mass Index, Diabetes, Cardiovascular Risk.