ESPE Abstracts (2015) 84 P-2-360

Increasing Waist/Height Ratio and BMI Z-Score are Associated with Increased Comorbidities in Obese Youth, although Neither Accurately Identifies those with Abnormal Glucose Metabolism

Kung-Ting Kaoa,b, Erin Alexanderb,c, Brooke E Harcourta,b, Zoe McCalluma,c, Melissa Wakeb,c, George Wertherb,c & Matthew Sabinb,c

aDepartment of Paediatrics, University of Melbourne, Melbourne, Victoria, Australia; bMurdoch Childrens Research Institute, Victoria, Australia; cThe Royal Children’s Hospital Melbourne, Melbourne, Victoria, Australia

Background: At a population level, increasing age/sex corrected BMI Z-score (BMI-Z) is associated with increased risk of complications. It is unclear whether severity of obesity is a good predictor of comorbidities within groups of obese children. This knowledge is required to inform clinical management and pathways of care.

Objective and hypotheses: In obese youth, to identify whether 1 increasing BMI-Z+/− waist/height ratio(WHtR) is associated with more comorbidities, and two activity levels and/or dietary factors show associations with comorbidities.

Method: Anthropometric and comorbidity data were collected from obese paediatric patients attending the weight management service at The Royal Children’s Hospital (Melbourne). Activity level (Actical accelerometry) and dietary consumption (Australian Food Frequency Questionnaire) data were additionally collected. Statistical analysis was performed using χ2, one-way ANOVA, Pearson’s correlation tests and linear regression as appropriate.

Results: There were no significant differences in cohort demographics (n=349, male; 169, age; 10.6(±3.6) years, BMI-Z; 2.46(±0.46). Comorbidities were common in the cohort: hypertension (50%), IGT (38%), non-alcoholic fatty liver disease (NAFLD, 32.9%), hyperlipidaemia (23.9%), obstructive sleep apnoea (OSA, 22.3%), polycystic ovarian syndrome (14.4%), mental health disorders (11.4%), type 2 diabetes (3.6%), eating disorders (1.4%) and neurological complications (0.3%). Both increased WHtR and BMI-Z were associated with comorbidities, with WHtR being the better predictor (P<0.01). Neither was associated with IGT, fasting glucose or 2-h glucose. Lower daily vitamin C and higher vitamin A and retinol consumption were also significantly associated with comorbidities, while reduced activity levels showed no association.

Conclusion: WHtR better associates with comorbidities than BMI-Z in an obese paediatric population, but neither predicts the presence of abnormal glucose metabolism. Alterations in dietary micronutrient consumption may be an important association for the development of comorbidities in this group of patients.