Body composition, endocrine and metabolic profiles in adults with Prader-Willi syndrome.

OBJECTIVE: Prader-Willi syndrome (PWS) is a complex genetic disease associated with hypothalamic-pituitary dysfunction and severe obesity. The aim of the present study was to describe the relationships between body composition, metabolic and hormonal profiles in PWS adults.

METHOD: Forty six adults with genetically verified PWS, 25 women and 21 men, median age 28 years were studied. Body composition was evaluated by standard anthropometric procedures and with computed tomography (CT) of the abdomen and at the mid-femur level. CT of abdomen was compared to 22 healthy, unmatched adults. Circulating lipids were measured and oral glucose tolerance test (OGTT) and hormonal screening including GH secretory capacity (GHRH/arginine test) was carried out.

RESULTS: Median body mass index (BMI) was 27.2 kg/m(2), with women being more obese than men. Sixteen patients had dyslipidaemia, 10 impaired glucose tolerance and seven had diabetes. Fifty percent were hypogonadal and six fulfilled BMI related criteria for growth hormone deficiency (GHD). Visceral to subcutaneous abdominal fat ratio was reduced in PWS. Visceral abdominal fat fraction correlated with both subcutaneous fat, BMI and peak GH-response. Thigh muscle volume was about half of the thigh fat volume. Beneficial effects of sex-steroid replacement on body composition were not observed.

CONCLUSIONS: Body fat was primarily located subcutaneously and metabolic consequences of obesity limited. The abnormal body composition similar to that in non-PWS GHD adults increases the interest of GH treatment in the prevention of obesity in adults with PWS.