Prader-Willi syndrome (PWS) is a genetic disorder affecting almost 1 in 16000 live births.(1) It often presents with hypotonia and failure to thrive (FTT) as an infant, with later progression to hyperphagia and obesity.(2) The aim of this study was to examine the association between duration of FTT and age of onset and severity of overweight/obesity in children with PWS. It was hypothesised that longer duration of FTT would be associated with more severe and earlier onset overweight/obesity.
A retrospective pilot study was conducted, examining auxological data from hospital records of children with a genetic diagnosis of PWS attending Paediatric Endocrinology clinics at Sydney Children’s Hospital and Royal North Shore Hospital. Height and weight standard deviation (SD) were calculated using CDC 2000 LMS method, with BMI SD included above 24 months age, using the same method. Recovery from FTT was defined as weight SD change by greater than +0.67.(3) Age of BMI SD +1.04 and +1.64 were considered age of overweight and obesity, respectively. Pearson correlation was used to investigate the association between duration of FTT and onset and severity of overweight/obesity. Cases were excluded if data was incomplete.
Auxological data from 29 children with PWS were extracted. Five cases were excluded from analysis due to incomplete data. A Pearson correlation coefficient was computed to assess the linear relationship with between duration of FTT and age of onset of overweight/obesity and found no correlation, r=-0.080, p=0.776 (n=16). There was a non-significant positive correlation between duration of FTT and severity of overweight/obesity, r=0.381, p= 0.066 (n=24).
The current pilot study identified a statistically non-significant trend of longer duration of FTT being associated with more severe degree of overweight/obesity. We can hypothesise that optimising nutritional treatment may have benefits in reducing future obesity risk in this population. Larger studies are required.