Background

Puberty is associated with changes in body composition, a transient decrease in insulin sensitivity, and is a period of increased type 2 diabetes risk in obese youth. However, little is known about the impact of puberty on abdominal fat compartmentalization. We aimed to study changes in subcutaneous (SFat), visceral (VFat), and hepatic fat fraction (HFF) from early to late puberty.

Methods

A subset (n=19) of normal weight (NW, n=12, 58% male, BMI %ile 52±27%) and obese (n=7, 28% male, BMI %ile 98±1.5%) youth participating in the Health Influence of Puberty (HIP) Study had HFF and L4-5 % visceral (VFat) and % subcutaneous fat (SFat) measured by MRI at baseline (Tanner 2-3, T2-3) and at Tanner 5 (T5). Paired t-tests compared differences in liver and abdominal fat composition between T2-3 and T5.

Results

Compared to NW youth, youth with obesity had higher %SFat (52.8±5.7 vs. 19.8±9.3%, p<0.0001), %VFat (12.6±2.6 vs. 7.5±3.6%, p=0.003), and HFF (8.3±7.1 vs. 1.4±0.6%, p=0.002) at baseline. In NW youth, %SFat increased (+4.4±8.1%, p=0.08) and %VFat decreased (-1.2±1.5%, p=0.01), such that the VFat:SFat ratio decreased (-0.01±0.05, p=0.0001) from early to late puberty and HFF increased (+0.88±0.98%, p=0.01). There were no significant changes in %SFat, %VFat, VFat:SFat or HFF over time in obese youth.

Conclusions

In addition to its impact on insulin sensitivity, puberty appears to affect abdominal fat compartmentalization, with a more metabolically favorable distribution as puberty progresses in healthy, NW youth. Paradoxically, hepatic fat increased in NW youth during the same time. As expected, obese youth show metabolically unfavorable abdominal fat distribution during adolescence, but no additional impact of pubertal progression. Future studies are needed evaluating the transition into puberty to better understand the impact of puberty of fat compartmentalization in youth with obesity.