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, 510 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.
18 - 21 May 2019
European Society of Endocrinology