Identification of growth patterns of preterm and small-for-gestational age children from birth to 4 years - do they catch up?

Background A legitimate indication for growth hormone (GH) therapy in children born too light or short at birth [small-for-gestational age (SGA)] exists in Germany and the European Union only if special criteria are met. Methods We conducted a longitudinal, multi-centered study on full-term appropriate-for-gestational age (AGA, n=1496) and pre-term born SGA (n=173) and full-term SGA children (n=891) in Germany from 2006 to 2010. We analyzed height, weight, body mass index (BMI) and head circumference. Results Pre-term or full-term born SGA children were shorter, lighter and had a lower BMI from birth until 3 years of age than full-term AGA children. The growth velocity of the analyzed anthropometric measurements was significantly higher in pre-term and full-term SGA children exclusively in the first 2 years of life than in AGA children. The criteria for GH treatment were fulfilled by 12.1% of pre-term SGA children compared to only 1.3% of full-term SGA children. Conclusion For children that do not catch up growth within the first 2 years of life, an earlier start of GH treatment should be considered, because a catch-up growth later than 2 years of life does not exist. Pre-term SGA-born children more frequently fulfill the criteria for GH treatment than full-term SGA children.

Age-related stature and linear body segments in children with X-linked hypophosphatemic rickets.

Children with X-linked hypophosphatemic rickets (XLH) are prone to severe stunting. A multicenter mixed-longitudinal study was conducted to assess age-related stature, sitting height, arm and leg length in XLH patients on continuous treatment with phosphate and calcitriol. Mean standard deviation scores (SDS) for all body dimensions were markedly reduced and differed significantly among each other at the initial and subsequent evaluations (baseline: stature -2.48 SDS; sitting height -0.99 SDS; arm length -1.81 SDS; leg length -2.90 SDS; each p<0.001). A strong association between stature and leg length (r (2)=0.87, p<0.001) was noted. Leg length SDS decreased progressively during childhood (2-9 years) and adolescence (12-15 years; each p<0.001). Sitting height SDS increased significantly during late childhood, indicating uncoupled growth of the legs and trunk and resulting in an ever increasing sitting height index (i.e. ratio of sitting height to stature; age 2 years 2.0 SDS; age 10 years 3.3 SDS; p<0.001) that was associated with the degree of stunting (r (2)=0.314, p<0.001). Mean serum phosphate levels were positively associated with stature and leg length, but negatively with sitting height index. Based on these results, we can conclude that growth of the legs and trunk is uncoupled in XLH and related to serum phosphate levels.