BODY COMPOSITION IN FEMALES WITH ADOLESCENT IDIOPATHIC SCOLIOSIS (AIS)

Abstract

Background: To compare height-adjusted fat and fat-free mass components of body composition in girls with adolescent idiopathic scoliosis to young adolescents with eating disorders. Adolescent idiopathic scoliosis (AIS) has been linked with low bone densities. Animal and human studies have shown that bone densities are influenced by a wide variety of inter-related factors that includes body fat, oestrogen levels, nutritional status and energy balance. Anthropometric studies have reported girls with AIS as being taller and more slender than their age-matched peers and that they also exhibit complex patterns of body asymmetry, particularly in the upper limb. There are also some studies report eating disorders in this population.

Methods: Height-adjusted fat and fat-free mass components of body composition were examined. Fat mass index (FMI) and fat-free mass index (FFMI) were calculated and normalised for height and were superimposed onto UK 1990 growth reference data. The data for left and right limb length was also compared. A sample of 325 girls with AIS referred to the specialist spinal unit in Liverpool during the period 1970–1990.

Results: The fat mass index and fat-free mass index were reduced in this sample of AIS subjects compared with normal reference children, but were similar to those diagnosed with eating disorders (anorexia nervosa). The cohort also exhibited significant upper limb asymmetry.

Conclusion: The findings suggest that this population has significantly low fat mass compared to normal, healthy reference values. Since fat mass reflects energy balance, nutritional status (possibly eating disorders) and is closely linked to endocrine function, the implications of reduced fat mass on growth, bone mass accretion and the aetiology of AIS merit further investigation.