Systematic Review and Meta-Analysis of Co-morbidities Associated with Child and Adolescent Obesity

Background Evidence for the impact of obesity on health outcomes has largely focussed on adults; however, a growing body of research has reported the prevalence of co-morbidities in children. We aimed to identify population-based research of co-morbidities associated with obesity in children aged 5-18 years, and to estimate the prevalence and prevalence ratio of each co-morbidity using meta-analyses. Methods We searched Embase, Medline, Medline-in-Process, PsycINFO, and Web of Science; from database inception to 14th January 2018. Population-based observational studies reporting prevalence of obesity-associated co-morbidities by weight category (healthy weight/overweight/obese) in children aged 5-18 years from any country were eligible. Non-English articles were excluded. Co-morbidity prevalence, stratified by weight category, was extracted and prevalence ratios (relative to healthy weight) were estimated using random effects meta-analyses. Quality was assessed using the Joanna Briggs Institute’s Critical Appraisal Checklist. Results Of 9183 abstracts, 53 eligible studies (1,553,683 participants) reported prevalence of eight co-morbidities or risk markers including diabetes, hypertension, dyslipidaemia, and NAFLD. For each co-morbidity multiple definitions were used (e.g. diabetes risk identified via fasting plasma glucose ≥100mg/dL (≥5.6mmol/l); GTT 120 minute post-test glucose ≥200mg/dl and insulin resistance HOMA >3.16) which were analysed and reported separately. Eligible evidence for psychological co-morbidities was lacking. Meta-analyses suggested prevalence ratio for obese relative to healthy weight groups for pre-diabetes (defined as fasting glucose ≥100mg/dL) was 1.4 (95% CI 1.2, 1.6), high LDL at 3.3 (1.6, 6.8), high blood pressure >90 percentile at 4.4 (2.2, 8.8), NAFLD at 26.1 (9.4, 72.3); and self-reported asthma at 1.7 (1.4, 2.0). Interpretation In the general population, children with overweight or obesity have a significantly higher prevalence of comorbidities relevant to those of a healthy weight. These data provide yet more evidence of the need for decision makers at global, national and local levels to support the development and implementation of effective treatment and prevention strategies for child obesity.