Objective: To investigate body weight and the body mass index (BMI) in girls with adolescent idiopathic scoliosis (AIS).
Methods: Six hundred and thirteen AIS female patients admitted from January 2005 to January 2007 and 449 healthy girls were recruited for this study with a range of age from 12 to 16 years old. The direct indexes included body height, body weight and date of birth. The indirect indexes included corrected body height, BMI and corrected BMI. The corrected body heights of AIS patients were adjusted by using the greatest Cobb angle to correct for spinal deformity according to Bjure's formula. Two-tailed Student's test was used for group comparison.
Results: In the AIS patients, the maximum Cobb angle was (31 +/- 11) degrees (11 degrees to 77 degrees). The corrected body height were significantly higher in AIS patients than in the normal controls from 12 to 16 years old (P < 0.05). The body weight were significantly lower in AIS girls than in normal controls from 12 to 16 years of age (P < 0.01). From 12 to 16 years of age, the BMI were (17.6 +/- 1.9), (17.9 +/- 2.5), (17.9 +/- 2.1), (18.6 +/- 2.3) and (19.0 +/- 1.9) kg/m2 in AIS patients; while the BMI were (19.5 +/- 3.4), (19.8 +/- 3.0), (20.4 +/- 2.9), (20.4 +/- 2.8) and (20.2 +/- 2.2) kg/m2 in normal controls. The BMI were significantly lower in AIS girls than the normal controls from 12 to 16 years of age (P < 0.001).
Conclusions: After the onset of puberty, significantly longer corrected height, lower body weight and lower BMI were found in AIS patients. Results of this large-scale study revealed the presence of abnormal growth in AIS patients during peripubertal development.