Increasing Burden of Clinical and Cardiometabolic Comorbidities by Bmi Category in Obese Children in South Africa

Objective: Conducted at a tertiary hospital in South Africa, this study described the presentation of childhood obesity and their related comorbidities by body mass index (BMI) categories in <12-year-old children assessed from 2012 to 2022. Design and method: In this retrospective review, socio-demographic characteristics, lifestyle behaviours, physical examination and biochemical data were extracted from electronic records. World Health Organisation child growth reference defined obesity as z-score >=2 standard deviations (SD) for 5-19-year-olds, and z-score >=3 SD for <5-year-olds. BMI was calculated for the included participants and categorised as BMI<30 kg/m2, BMI 30-35 kg/m2 and BMI>=35 kg/m2. Systolic BP (SBP) and/or diastolic BP(DBP) >=95th percentile for age, gender and height defined hypertension. SBP or DBP>=90th but <95th percentile defined prehypertension. Oral glucose tolerance tests or random blood glucose determined type 2 diabetes and prediabetes. Dyslipidaemia was considered present with any abnormality of total cholesterol, low-density lipoprotein cholesterol, high-density lipoprotein cholesterol or triglycerides. Results: Among 430 obese participants, mean age 7.3 years, 52.1% (n=224) were male and 27.9%(n=120) were <=5-years-old. Distribution by BMI categories was BMI<30 kg/m2: 56.3% (n=242), BMI 30-35 kg/m2: 26.3% (n=113) and BMI>=35 kg/m2: 17.4% (n=75). Unhealthy lifestyle behaviours were common and increased with greater BMI category (BMI<30 kg/m2, BMI 30-35 kg/m2 and BMI>=35 kg/m2) (p>0.05): 36%, 46% and 57.3% spent <30 minutes/day on physical activity, 37.7%, 46.9% and 57.3% spent >2 hours/day on screen time and 42.6%, 46.9% and 66.7% consumed soft drinks daily. Obesity-related clinical characteristics of acanthosis nigricans, snoring/stertor, adeno-tonsillar hypertrophy, asthma, skeletal abnormalities and obstructive sleep apnoea were prevalent and increased with higher BMI (p<=0.013 for all). BP increase significantly across BMI categories: SBP:113.2mmHg, 119.2mmHg, 123.6mmHg (p<0.001); DBP:64.3mmHg, 68.9mmHg, 70.8mmHg(p<0.001). Hypertension prevalence was high across BMI categories: 42.6%, 55.8%, 42.7%(p=0.057) as was pre-hypertension: 13.2%, 8.8%, 17.3%. Dysglycaemia prevalence was 5.0%, 6.2% and 2.7%(p=0.320). Dyslipidaemia was high at 23.6%, 38.9% and 38.7%(p=0.420). Conclusions: Clinical and cardiometabolic comorbidities were common in obese children and generally increased with higher BMI. Intensive interventions, addressing unhealthy diets, low activity levels and sedentary behaviours, are needed to prevent worsening of comorbidities and for improvements in cardiometabolic profiles.