EFFECTS OF BODY-FAT ON VENTILATORY FUNCTION IN CHILDREN AND ADOLESCENTS - CROSS-SECTIONAL FINDINGS FROM A RANDOM-POPULATION SAMPLE OF SCHOOL-CHILDREN

Childhood obesity is associated with a range of adverse consequences, and the prevalence is increasing in developed nations. Most of the lit erature on obesity and ventilatory function in children concerns sampl es selected for gross obesity with relatively little detail available from random population samples. This report examines the effect of tot al body fat as a percentage of weight (TBF%) on ventilatory function i n a nationally representative sample of 2,464 Australian school childr en aged 9, 12, and 15 years. Forced vital capacity (FVC) and forced ex piratory volume in 1 s (FEV1) were used as measures of ventilatory fun ction. TBF% was estimated from skinfold thickness measurements. Ventil atory function was adjusted (for height and then for both height and w eight) using linear regression on a logarithmic scale. Adjustment was performed within separate strata of age and gender. Analysis of covari ance was used for hypothesis testing. Height-adjusted FVC and FEV1 val ues increased significantly with increasing weight within each age and gender group and for all subjects combined (P < 0.0001). The effect o f TBF% independent of lean tissue was examined using FVC and FEV1 valu es adjusted for both height and weight, because body weight measures b oth lean and fat mass. Adjusted FVC and FEV1 values decreased signific antly with increasing TBF% within each age and gender group and for al l subjects combined (P < 0.0001). Ventilatory function decreased with increasing proportions of body fat. This is consistent with previous f indings on lean tissue mass and ventilatory function, Although the mag nitude of the effect was relatively small in clinical terms, from a pu blic health perspective our findings indicate yet another adverse cons equence of childhood obesity. (C) 1997 Wiley-Liss, Inc.