Magnetic Resonance Imaging of Abdominal Adiposity in a Large Cohort of British Children.

Objective: To describe abdominal adipose tissue distribution in a large sample of contemporary British children; to determine the influence of gender, stage of maturation and body mass index (BMI) on abdominal adipose tissue distribution; and to compare the ability of BMI and waist circumference to predict abdominal adipose tissue.

Subjects and methods: A total of 74 boys (mean age 13.4±0.4 years) and 96 girls (mean age 13.5±0.5 years) were selected from volunteer children enrolled in the Avon Longitudinal Study of Parents and Children (ALSPAC). Height, weight and waist circumference were measured and BMI calculated. Stage of sexual maturation was available for 113 children using a self-report questionnaire based on Tanner's criteria. Magnetic resonance imaging was used to assess subcutaneous abdominal adipose tissue (SAAT) and intra-abdominal adipose tissue (IAAT) volumes and patterning.

Results: Boys had lower levels of IAAT (P=0.036) and SAAT (P=0.003) than girls. IAAT and SAAT were higher in overweight and obese boys and girls when compared with normal weight children (P<0.0001). This pattern was also reflected in waist circumference groups. Boys had higher IAAT/SAAT ratios than girls, indicating proportionately more adipose tissue deposited intra-abdominally (P=0.002). However, both boys and girls deposited less than 10% of their abdominal fat as internal adipose tissue. WC predicted 67.4% of the variance in IAAT (P<0.001), and BMI predicted 84.8% of the variance in SAAT (P<0.001). However, BMI as the best single predictor explained only 8.4% of the variance in the IAAT/SAAT ratio (P<0.001).

Conclusions: At this age and stage of sexual maturation, the amount of IAAT remains relatively small. WC and BMI offer a feasible alternative to the MRI estimation of IAAT and SAAT, respectively, in a population-based sample of boys and girls.