Age-appropriate body mass index in children with achondroplasia: interpretation in relation to indexes of height

Abstract

Background: Achondroplasia is the most common short stature skeletal dysplasia, with an estimated worldwide prevalence of 250 000. Body mass index (BMI)-for-age references are required for weight management guidance for children with achondroplasia, whose body proportions are unlike those of the average stature population. Objective: This study used weight and height data in a clinical setting to derive smoothed BMI-for-age percentile curves for children with achondroplasia and explored the relation of BMI with its components, weight and height. Design: This was a longitudinal observational study of anthropometric measures of children with achondroplasia from birth through 16 y of age. Results: The analysis included 1807 BMI data points from 280 children (155 boys, 125 girls) with achondroplasia. As compared with the BMI of peers of average stature, the BMI in children with achondroplasia is higher at birth, lacks a steep increase in infancy and a later nadir between 1 and 2 y of age, and remains substantially higher through 16 y of age in both sexes. Patterns of change in height and weight in children with achondroplasia are unique in that there is no overlap in the height distribution after 6 mo of age and no spike in height velocity during infancy or puberty-the 2 periods of greatest linear growth in individuals of average stature. Conclusions: Sex-and age-specific BMI curves are available for children with achondroplasia (birth to 16 y of age) for health surveillance and future research to determine associations with health outcomes (eg, cardiovascular disease, diabetes, and indication for and outcome of surgery).Am J Clin Nutr 2008;88:364 -71.

Enzyme replacement therapy for mucopolysaccharidosis VI: Growth and pubertal development in patients treated with recombinant human N-acetylgalactosamine 4-sulfatase

“…BMI was in the normal range with the mean Z scores above zero for all age groups at baseline (Table 2). This is consistent with other skeletal dysplasias, MPS IVA [20] and achondroplasia [15], which demonstrate BMI patterns that are shifted up in relation to the CDC reference curves. As evidenced by a preponderance of Tanner scores of 1 and 2, MPS VI study patients were primarily pre-pubertal or in an early stage of puberty at baseline (45/54, 83%; Table 2), although 19% of the overall group was classified as having delayed onset or progression of puberty at baseline.…”

“…Although growth charts are not available for MPS VI, accelerated growth has been reported in the first years of life in MPS VI with advanced bone maturation at birth, followed by slowing growth rate and growth failure after 2 years of age [14]. This pattern of growth is similar to those described for MPS IVA and achondroplasia, two other skeletal dysplasias [15,20]. …”

Low bone mineral density in achondroplasia and hypochondroplasia

“…15 Although high BMI has long been thought to be protective for bone mass, the relationship between BMI and osteopenic conditions has been inconclusive, with conflicting findings. Fasolino and Whitright reported lower BMI with high rates of osteopenia and osteoporosis.…”

Growth references for height, weight, and head circumference for Argentine children with achondroplasia

“…Specific growth standards for genetic disorders have been prepared for children in ACH, Turner Syndrome and other conditions [8,[10][11][12][13]31]. They are useful not only for detecting additional conditions which could affect growth, but also for estimating final height and hence evaluating the impact of growth-promoting treatments [22,31].…”