DAILY ENERGY-EXPENDITURE AND PHYSICAL-ACTIVITY IN SURVIVORS OF CHILDHOOD MALIGNANCY

Changes in body composition, in particular the onset of obesity, may r esult from reductions in total daily energy expenditure (TDEE) as a co nsequence of relative physical inactivity. Children previously treated for acute lymphoblastic leukemia (ALL) become obese, yet the mechanis m remains undefined. TDEE and physical activity levels [PAL = TDEE/bas al metabolic rate (BMR)] were measured in 34 long-term survivors of AL L and compared with results from 21 survivors of other malignancies an d 32 healthy sibling control subjects using the hex-heart rate techniq ue. Body composition was measured by dual energy x-ray absorptiometry. The median TDEE was reduced in the ALL group (150 kJ . kg d(-1)) comp ared with other malignancies and controls (207 and 185 kJ . kg d(-1). respectively, p < 0.01). This reduction was accounted for mainly by a relative decrease in the PAL of the ALL group (1.24) compared with bot h other malignancies and controls (1.58 and 1.47, respectively, p < 0. 01). TDEE and PAL were correlated with percentage body fat (r = -0.39, p < 0.001 and r = -0.24, p < 0.05, respectively). Obesity in survivor s of ALL may, in part, be explained by a reduction in TDEE as a conseq uence of reduced PAL. The cause of such reduction is uncertain.