Tracking body fat distribution during growth: using measurements at two occasions vs one

Objective: To investigate whether within-individual variation is a factor i n the generally reported poor tracking of central body fat distribution (CB FD) during development and whether two measurements of CBFD during each mea surement occasion would improve the estimate of tracking over time. Methods: A longitudinal study compared the results of two measurements of b ody fat (BF) and CBFD during each measurement occasion to the results of on e measurement of BF and CBFD during each occasion every 4 months over 1-3 y . A total of 345 boys and 333 girls in three age cohorts of 8, 11 and 14 y at baseline were examined, BF variables were: body mass index (BMI); fat ma ss and percentage body fat from bioelectrical impedance; two skinfold sums; and abdominal circumference. CBFD variables were: waist/hip and waist/thig h ratios; conicity; and log upper-lower skinfold ratio. Results: Three-year tracking of BF varied from 0.79 to 0.90 for one- and fr om 0.81 to 0.93 for two-occasion measurements showing no apparent sex- or c ohort-effects. Three-year tracking of CBFD was lower than that of BF (0.68- 0.75), but improved significantly with two-occasion measurements (0.75-0.82 ). Conclusions: With in-individual variation is a significant factor in report ed low tracking of CBFD in childhood. Estimates of tracking currently in th e literature may underestimate the predictive value of CBFD, possibly becau se this research has used one-occasion measurement. The increased use of tw o-occasion measurement should significantly improve the tracking of CBFD du ring development and provide a more realistic understanding of its predicti ve value.