Age at adiposity rebound and the relevance for obesity: a systematic review and meta-analysis

To understand the sex difference in age at adiposity rebound (AR), integrate the prevalence of early AR (EAR), and provide a quantitative association between early age at AR and overweight/obesity.

Literature review was conducted in different databases, including the Web of Science, PubMed, EMBASE, Wiley, Chinese National Knowledge Infrastructure, and ScienceDirect databases up to August 2021. Studies that reported data related to AR were considered for inclusion. Pooled effect sizes and their respective 95% confidence intervals (CIs) were calculated using random effects models, depending on the size of heterogeneity. Heterogeneity was tested by using the I² statistics.

28 studies with a combined sample size of 106,397 people were included in the final meta-analysis. Girls had a significantly earlier age of AR than boys (mean difference = 3.38 months; 95% CI 2.14-4.63). The overall prevalence of EAR was 40% (95% CI 31% to 50%), and the prevalence in girls was 5% higher than that in boys based on the definition of age at AR < 5.0-5.1 years. The overall pooled prevalence of EAR showed an increasing trend by child's birth year [1934-1973]: 29% (95% CI 22% to 37%), 1991-2001: 35% (95% CI 26% to 44%), and 2002-2009: 52% (95% CI 40-63%). Early age at AR (age at AR < 5.0-5.1 years) was associated with a significantly increased risk of overweight/obesity (OR = 5.07; 95% CI 3.60-7.12), overweight (OR = 3.10; 95% CI 1.69-5.70), and obesity (OR = 6.97; 95% CI 4.32-11.26) from the preschool period to adulthood.

The overall prevalence of EAR is increasing, and girls experience AR earlier than boys. The early age at AR in children may be an early and effective marker of obesity.