ISSN 1470-3947 (print) | ISSN 1479-6848 (online)

Endocrine Abstracts (2019) 63 GP150 | DOI: 10.1530/endoabs.63.GP150

Increased prevalence of overweight and obesity and its clinical predictors in children affected by x-linked hypophosphatemia

Volha V. Zhukouskaya1,2, Anya Rothenbuhler1,3, Annamaria Colao4, Carolina Di Somma4,5, Peter Kamenicky1,6,7, Séverine Trabado7,8, Dominique Prié9,10, Christelle Audrain1, Anna Barosi1, Christèle Kyheng11, Anne-Sophie Lambert1,3 & Agnès Linglart1,3,7


1APHP, Reference Center for Rare Disorders of the Calcium and Phosphate Metabolism, Filiere OSCAR and Platform of expertise for rare diseases Paris-Sud, Bice^tre Paris-Sud Hospital, Le Kremlin Bicêtre, France; 2Department of Clinical Medicine and Surgery, Division of Endocrinology, University of Naples Federico II, Naples, France; 3APHP, Department of Endocrinology and Diabetology for children, Bicêtre Paris Sud Hospital, Le Kremlin Bicêtre, France; 4Department of Clinical Medicine and Surgery, Division of Endocrinology, University of Naples Federico II, Naples, Italy; 5IRCCS SDN, Naples, Italy; 6APHP, Department of Endocrinology and Reproductive Diseases, Bicêtre Paris Sud Hospital, Le Kremlin Bicêtre, France; 7Paris Sud – Paris Saclay University, Faculté de Médecine, Le Kremlin Bicêtre, France; 8APHP, Department of Molecular Genetics, Pharmacogenetics and Hormonology, Bice^tre Paris-Sud Hospital, Le Kremlin Bicêtre, France; 9Université Paris V, Faculté de Médecine, Paris, France; 10Hôpital Necker Enfants Malades APHP, INSERM U1151, Paris, France; 11APHP, Department of Adolescent Medicine, Bicêtre Paris Sud Hospital, Le Kremlin Bicêtre, France.


Background/aim: X-linked hypophosphatemia (XLH) is a rare disease characterized by low phosphate level. Scientific evidence points to link between hypophosphatemia and obesity in general population. The aim of our longitudinal observational study was to investigate the prevalence of obesity and associated factors in a large cohort of children with XLH.

Patients/methods: We selected 172 XLH-children of 5-20 years (113 girls/59 boys). Anthropometric parameters (weight, height, BMI) were collected at birth and during follow-up at mean age of 5.3-8.2-11.3-15.9 years (group 1-2-3-4, respectively). In each group, subjects were classified based on International Obesity Taskforce (IOTF) cut off values of BMI for age and sex as overweight or obese (IOTF 25-30 or ≥30 kg/m2, respectively).

Results: In each age-group, almost 1/3 of XLH-patients were classified as overweight/obese (29.4% vs 28.7% vs 27.5% vs 36.7% for group 1-2-3-4, respectively). Children without XLH-family history had significantly higher BMI-IOTF at every point of follow-up (P=0.015), compared to those with positive XLH-family history. Similarly, higher BMI-IOTF is significantly associated with treatment duration (23.3±4.4 vs 23.8±3.8 vs 25.2±4.5 kg/m2, for subjects with treatment duration of <5, 5–10 and >10 years, respectively, p for trend=0.025). Multiple regression analysis confirmed that treatment length and lack of XLH-family history are positively associated with higher BMI-IOTF.

Conclusion: 1/3 of XLH-children have phenotypically unfavourable metabolic profile expressed as increased prevalence of overweight/obesity in comparison to general population. Lack of XLH family history and length of treatment increase the risk of higher BMI-IOTF. BMI should be carefully followed in children, and later adults, with XLH.