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Adolescent idiopathic scoliosis (AIS) is a serious 3-dimentional deformity of the spine affecting mostly girls. The prevalence rate is 3%-4% in Hong Kong. Generalised osteopenia are found in AIS patients. This study attempted to study whether low bone mineral density (BMD) is related to calcium intake in AIS. 582 AIS patients & 206 healthy controls aged 11-16 years were enrolled. Areal BMD (aBMD) and volumetric BMD (vBMD) were evaluated by DXA (Norland-XR-36) and pQCT (Densiscan-1000) respectively. Calcium and other nutrients intakes were assessed by a food-frequency method. The results showed that absolute calcium intake of the subjects were low (< 500 mg/d). Mean calcium intake of AIS girls was significantly higher than that of controls[(441 +/- 344) mg/d vs. (390 +/- 281) mg/d, P = 0.015]. BMD of AIS was significantly lower than that of controls at most skeletal sites from age 11-16 years (P < or = 0.05). The percentage difference in BMD increased with age between the AIS and control group. Furthermore, calcium intake was significantly correlated with BMD at most skeletal sites from age 15-16 years. However, this association was not found in the controls. Calcium intake was an independent determinant to predict variation of BMD after controlling for confounding variables in multivariate analysis. It is suggested that absolute calcium intake of AIS was low. BMD at various skeletal sites of the AIS was consistently lower than those of controls across different adolescent years, and that the correlation between calcium intake and BMD occurs only in AIS but not in healthy control girls implying the importance of calcium in bone mineral gain among the AIS, and it also reflected an abnormal mechanism of calcium homeostasis and bone turnover in AIS. Further calcium interventional study is warranted to confirm the effect of calcium on BMD acquisition in AIS.

Study Design: A cross-sectional study of anthropometric parameters in adolescent idiopathic scoliosis (AIS)., Objective: To compare anthropometric parameters and growth pattern of AIS girls versus normal controls during peri-puberty., Summary of Background Data: Abnormal pattern of growth has been reported in AIS patients. The sequential changes of growth and the correlation with curve severity have not been properly studied., Materials and Methods: Five hundred ninety-eight AIS girls and 307 healthy girls entered the study. Weight, height, body mass index (BMI), arm span, sitting height, and leg length were determined using standard techniques. Height and sitting height were adjusted by using the greatest Cobb angle to correct for spinal deformity (Bjure's formula). Puberty was graded by Tanner's staging., Results: AIS girls had significantly shorter height (P = 0.001), corrected height (P = 0.005), arm span (P = 0.022), sitting height (P = 0.005) and leg length (P = 0.004) than the controls at pubertal stage I. From pubertal stages II through V, corrected height (P

Study Design: Magnetic resonance imaging (MRI) was used to compare quantitatively the position of the cerebellar tonsil in neurologically normal adolescents with that in idiopathic scoliosis (AIS) patients and age-matched healthy controls., Objectives: To redefine the normal reference level of the cerebellar tonsil in healthy adolescents and to compare the differences in tonsillar level with AIS of different severities., Summary of Background Data: Asymptomatic Chiari I malformation has been reported not infrequently in children and adolescents with AIS. The definition of tonsillar herniation and its variations with sex, age, and curve severities have not been clarified., Methods: Sagittal MRI of hindbrain was performed on 170 adolescents, including 117 patients with AIS and 53 age-matched healthy controls., Results: The cerebellar tonsillar tip in healthy patients was found at an average of 2.8 mm above the basion-opisthion reference line (BO line) (range, 0-10.5 mm), in contrast to the finding that 17.9% of the AIS patients had tonsillar tip below the BO line. The position of tonsil in the AIS group was lower than that in the healthy controls (P < 0.05), and the differences also increased with the severity of the curve (P = 0.027)., Conclusions: Using the current MRI reference standards, the incidence of tonsillar herniation could be significantly underestimated. According to our experience, any inferior displacement of a tonsil below the BO line in adolescents should be regarded as abnormal. Scoliosis could be an important manifestation of subclinical tonsillar herniation.