Visceral adipose tissue resides within the reference range in children with Prader-Willi syndrome receiving nutritional intervention on a regular basis

Subcutaneous adipose tissue is a positive predictor for bone mineral density in prepubertal children with Prader-Willi syndrome independent of lean mass

OBJECTIVES

Emerging evidence suggests a fat depot-specific relationship with bone mineral density (BMD) in children, particularly in those who are overweight/obese. However, this has not yet been investigated in detail in children with Prader-Willi syndrome (PWS), a genetic syndrome characterized by a decreased lean mass (LM) and increased fat mass (FM). The objective of this study is to investigate the relationships of LM and FM, particularly fat distribution, with bone mineral parameters.

METHODS

This is a retrospective and cross-sectional study. Forty-seven prepubertal Japanese children with PWS (22 males, mean age: 6.86 years) were included. No subjects had type 2 diabetes mellitus or osteoporotic medications. LM, FM, and BMD and bone mineral content in the total body less head and the lumbar spine were measured using dual-energy x-ray absorptiometry, in addition to subcutaneous/visceral adipose tissue (SAT/VAT), and the ratio of VAT to SAT (V/S) by computed tomography at the umbilical level. Bone mineral apparent density was calculated to correct for bone size.

RESULTS

LM positively correlated with bone mineral parameters after controlling for age, sex, growth hormone (GH) treatment, and FM. Although FM did not correlate with bone mineral parameters, compartment-specific analysis revealed that SAT positively and V/S negatively correlated with bone mineral parameters after controlling for age, sex, GH treatment and LM.

CONCLUSIONS

A compartment-specific effect of FM on bone mineral parameters was noted such that SAT was a positive predictor for BMD independent of LM in prepubertal children with PWS.

Growth hormone treatment for adults with Prader-Willi syndrome: another point of view

Growth hormone treatment for children with Prader Willi syndrome (PWS) has shown proven benefits not only in increasing final height but also with positive effects on body composition and motor development. In a recent letter to the editor, Hoybye and colleagues recommend growth hormone treatment for adults with PWS based exclusively on the genetic diagnosis and without regard for growth hormone secretory status. We question whether the benefits of growth hormone treatment in PWS adults, mainly improvement in body composition, are significant enough to justify the as yet unkown consequences of long-term treatment in an adult population. Morbidity and mortality in PWS are mainly due to complications of obesity, and growth hormone treatment does not result in a decrease in BMI or waist circumference. Increases in insulin-like factor-1 as a result of growth hormone treatment over the course of several decades in PWS adults raises concern over possible increase risk of cancer. Compliance with daily injections is likely to be poor. We suggest that efforts to provide appropriate dietary and exercise regimens may be more beneficial and cost-effective than advocating for growth hormone treatment for adults with PWS.