Anthropometry and body composition profile of girls with nonsurgically treated adolescent idiopathic scoliosis.

STUDY
DESIGN: Cross-sectional study with level III of evidence.
OBJECTIVE: To describe different anthropometric and body composition parameters of adolescent girls with adolescent idiopathic scoliosis (AIS), comparing them with the standards of a healthy age-matched population. SUMMARY OF BACKGROUND DATA: Body growth and development of adolescent girls with AIS seems to differ from the healthy subjects, especially at perpubertal stages. Young scoliotic adults have been found to be taller, lighter, and thinner than age-matched healthy population. Body composition profile taken from measurements of skin-fold thickness, bony diameters at different levels, and arm and legs perimeters has not been previously reported in AIS patients.
METHODS: A nonconsecutive series of 52 AIS girls (mean age: 13.9 years) with an average scoliotic curve of 27° Cobb (range: 20-58) underwent an anthropometric study. None of the AIS girls had been treated previously with spinal surgery. The control group consisted of 92 girls without spine deformity, matched in age (mean: 13.8 years). Weight, height, and skin-fold thickness in millimeters at six levels were measured. Body mass index (BMI), Ponderal index, percentage of body fat, percentage of muscular tissue, fat mass, lean body mass, muscular weight, bony weight, and residual weight were calculated using standard rules to estimate body composition. The somatotype components (endomorphy, mesomorphy, and ectomorphy) were calculated according to the Carter equations. RESULTS.: Compared with the control population, scoliotic girls had a significantly lower mean weight (51.4 ± 10.2 kg vs. 54.7 ± 8.1 kg; P < 0,05), a lower BMI (20.1 ± 3.4 vs. 21.4 ± 2.4; P < 0.001), and a higher Ponderal index (43.2 ± 2.4 vs. 42.2 ± 1.6; P < 0.01). Girls with AIS showed a progressive decrease of the BMI as the age increased. The percentage of body fat was also lower in scoliotic girls, without significant statistical differences (14.1 ± 3.8 vs. 15 ± 3.6). Out of the 52 AIS girls, 11 (21.2%) showed a BMI below 17.5, which has been considered the limit for anorexia. In the control group, only 3 of 92 girls (3.3%) had BMI below that level. The somatotype differed also between scoliotics and controls: higher in the ectomorphic component (3.29 ± 1.68 vs. 2.40 ± 1.11; P < 0.001), and lower in the mesomorphic component (2.86 ± 0.82 vs. 3.70 ± 1.11; P < 0.01) in AIS patients.
CONCLUSION: The differences in some anthropometric parameters (weight, IMC, IP) and in the somatotype suggest that the idiopathic scoliosis not only disturbs normal spine growth but also seems to have implications on the whole corporal development. Whether these changes could be related to abnormal spinal growth or subsequent to nutritional changes in AIS still remains uncertain. Presumably, some endocrine factors affecting body composition and growth might be involved in the etiology of idiopathic scoliosis.