ESPE Yearbook of Paediatric Endocrinology

Brief summary: This study investigated adipose tissue cellularity and functionality in more than 400 individuals with early-onset obesity (before the age of 18 years) versus late-onset of obesity (after the age of 18 years) compared to never-obese subjects. Individuals with obesity had increased subcutaneous white adipose tissue amounts resulting from a combination of increased size and numbers of fat cells.

Interestingly, individuals with early-onset obesity had a higher BMI and a 40% larger adipose fat mass than individuals with late-onset obesity without differences in visceral adipose tissue, adipose tissue cellularity, morphology and fat cell lipolysis. The increase in BMI per year was also higher in subjects with early-onset obesity compared to late-onset obesity.

These data suggest on the one side that there are similar mechanisms of white adipose tissue growth and expansion between early and late-onset of obesity. Irrespective of an early or late start, fat mass expands by a combination of increase in number and size of fat cells. However, on the other side, the dynamics of adipose tissue expansion seems faster in early-onset obesity compared to late-onset obesity. The most important difference between early and late-onset obesity is the more extensive white adipose tissue accumulation in early-onset obesity. Visceral adipose tissue expansion appears not to be influenced by the age of onset of obesity.

The more excessive subcutaneous white adipose tissue accumulation in early-onset obesity might be due to genetic factors, e.g. gene variants influencing energy homeostasis. Such factors, unfortunately have not been investigated in this study.