405 A snapshot study of obesity, gender and puberty in a multi-ethnic paediatric population

Background Obesity is an emerging public health concern in the United Kingdom. The prevalence of overweight and obese children in Birmingham is higher than the national average in England1. Royal College of Paediatrics and Child Health (RCPCH) reported that 1 in 5 primary school children are obese or overweight, and this increases to 1 in 3 in secondary school. During puberty, the body composition changes, but there is significant sexual dimorphism2. Objectives To determine the prevalence of high BMI (Body Mass Index) in a multi-ethnic paediatric cohort and define its relationship with gender and pubertal phase. Methods We collected data from General Outpatient Clinics and Paediatric Assessment Unit (PAU) between January – February 2020 and September – November 2020 respectively. Age, height (m) and weight (kg) for children between 5 and 16 years were recorded. Their BMI (kg/m2) were calculated and their corresponding BMI centiles determined using RCPCH Growth Charts. The relationship between high BMI (overweight and obese) and puberty within each gender group was studied. The pubertal age cut-off was set as the mean age of onset of Tanner Stage 2: 10.5 years for girls and 11.1 years for boys3. Results We obtained data from 260 patients (Outpatient: 104, PAU: 156). 32% (84/260) of the children were overweight and obese (overweight: 12.3%, 32/260) (obese: 20%, 52/260). The number of overweight girls and boys were similar (girls: 6.5%, 17/260) (boys: 5.8%, 15/260); however there are more obese boys than girls (boys: 12%, 30/260) (girls: 8%, 22/260). The relationship between pubertal phase and high BMI was different for both genders such that more girls with high BMI were pubertal, and more prepubertal boys have high BMI. In the outpatient data, 26% (8/30) pubertal girls and 30% (9/30) prepubertal boys were overweight or obese. In the PAU data, 31% (17/54) overweight or obese children were pubertal girls and 30% (16/54) were prepubertal boys. There were 28% (11/39) more girls with high BMI in the pubertal group compared to those in the prepubertal group, while 11% (5/45) more boys with high BMI in the pre-pubertal group (p=0.056, Fisher’s exact test). We accept that the sample size of this study is small, and more data collection is needed to see if we can obtain a statistically significant result. Conclusions Our study shows that the relationship between pubertal phase and high BMI differs between boys and girl. Future studies in larger cohorts are needed to examine this relationship and develop effective interventions to tackle obesity during pubertal period.