Endocrine Abstracts

Introduction: PWS children have higher body fat content and lower lean muscle mass as compared to normal population. Bioelectrical impedance analysis (BIA) estimates lean muscle mass and total fat content separately and thus is more useful than BMI. Continued weight gain despite treatment, can be distressing to patients and parents. We hoped to resolve this dilemma through serial body composition measurements.

Materials and methods: Patients and families are given pro-active advice on calorie intake and consistent dietary practices to prevent unnecessary weight gain. Three-day food diaries are used to assess macro and micro nutrient intake. GH therapy is used in eligible children. Height, weight and BMI are recorded at each visit and body composition measurements by BIA annually after 4 years of age.

Results: Retrospective case note review identified 6 children who had at least 1 BIA measurement; mean age was 9 years; mean body fat was 42.3% and mean lean muscle mass was 19.6 kg (reference −28% and 25.9 kg respectively).

Three children had four serial measurements and two were on GH. Patient 1 had 6.1 kg weight gain over 36 months, but body fat percentage decreased by 0.5% (34.9 to 34.4%). Patient 2 had 29.1 kg weight gain over 40 months, but body fat percentage decreased by 5.5% (48.7 to 43.2%). Patient 3 had 10 kg weight gain over 24 months but body fat percentage decreased by 1.8% (44.7 to 42.9%).

Conclusions: PWS children have much higher body fat percentage and considerably lower lean muscle mass as compared to normal children. Unnecessary fat weight gain can be minimised or even reduced with pro-active management. When inevitable weight gain occurs in PWS children, serial measurements help distinguish clearly between unnecessary fat weight gain and healthy lean muscle mass gain. No increment in percentage body fat can be reassuring to patients and their parents.