Among children with type 2 diabetes (T2D) obesity was determined to be an important risk factor for the disease but not a universal phenotype.
This conclusion, based on a global systematic literature review and meta-analysis, has prompted the authors to caution against forgoing screening for T2D in children with reference-range body mass index (BMI). T2D may be driven by factors other than obesity in these children, they state, which would substantially impact individual treatment and outcomes.
“Obesity is a major trigger for screening for T2D in clinical practice, yet the prevalence of obesity in the pediatric T2D population is unknown,” write M. Constantine Samaan, MD, MSc, associate professor in the department of pediatrics at McMaster University and a staff physician in the division of pediatric endocrinology at McMaster Children's Hospital in Hamilton, Ontario, Canada, and colleagues. “It is important to recognize whether T2D is diagnosed through ascertainment bias, whereby only children with obesity are screened and subsequently diagnosed with T2D.” Further, while the diverse and complex “weave of factors” that underly the pathogenesis of T2D in young children remain ill-defined, acknowledging the role in disease of social determinants of health in this population is essential.
For their systematic review and meta-analysis, Samaan and colleagues tapped MEDLINE, Embase, CINAHL, Cochrane Library and Web of Science from inception to June 2022 seeking observational studies with at least 10 participants with reports on the prevalence of obesity in individuals with pediatric T2D.
They defined the primary outcome of interest as pooled prevalence of obesity in T2D. Among multiple secondary outcomes calculated were pooled prevalence rates by sex and race as well as associations between obesity and glycemic control and dyslipidemia.
Overall investigators identified 57 articles for inclusion in the systematic review of which 53 (n=8942) were included in the meta-analysis.
Of the 57 studies 26 were cross sectional studies, 23 retrospective cohort studies, and 6 prospective cohort studies. Samaad et al report that 12 of the 57 studies did not report specific diabetes diagnostic criteria.
The research team found the overall pooled prevalence of obesity among pediatric patients with T2D was 75.27% (95% CI, 70.47-79.78; P<.001) with a prevalence of 77.24% at the time of T2D diagnosis among 4688 participants (95% CI, 70.55-83.34; P<.001). Noting that a considerable proportion of participants with T2D did not have obesity, the author’s deeper look revealed wide variations in the prevalence of overweight across studies—from 0% to 43.4% with the same range for the prevalence of normal weight (0% to 43.6%).
Pooled prevalence of obesity in boys was higher than in girls (78.65% vs 59.2%), the authors report, and the pooled odds ratio of obesity prevalence for boys vs girls was 2.1 95% CI, 1.33-3.31). Among racial and ethnic groups, prevalence of obesity appeared to be lowest among Asian participants (64.50% [95% CI, 53.28-74.99]), and highest among White participants (89.86% [95% CI, 71.50-99.74]). The investigators also found international regional differences, which they note may potentially reflect racial/ethnic differences. The prevalence of obesity among children with T2D was observed highest in North America (81%) followed by the Middle East (78%), Oceania (74%), Asia (69%), and Europe (68%).
Metaregression analyses found no significant correlations between prevalence of obesity and mean HbA1c levels, hypercholesterolemia, hypertriglyceridemia, or elevated LDL cholesterol levels. There was some suggestion of an association between obesity and low HDL-C (p=.04).
“Understanding the causes of T2D in children without obesity is crucial to define the etiology of their diabetes and to create effective management strategies for this cohort,” concluded investigators. “Further research is needed to evaluate the causes of sex- and race and ethnicity–based associations of diabetes with obesity and explore additional factors that may affect the risk of developing T2D apart from obesity in children.”
Reference: Ciobanu M, Deng J, Nadarajah A, et al. The prevalence of obesity among children with type 2 diabetes. JAMA Netw Open. 2022;5:e2247186. DOI: 10.1001/jamanetworkopen.2022.47186.