Patterns of obesity in boys and girls after treatment for acute lymphoblastic leukaemia

The frequency and pattern of obesity in survivors of acute lymphoblastic leukaemia (ALL) was examined in a retrospective analysis ofheight and weight at zero, two, and four years from diagnosis in 40 children (19 boys and 21 girls). The children had been treated according to the Medical Research Council protocols UKALL VIII and X, both ofwhich included cranial radiotherapy at a dose of 1800 cGy. Body mass index (BMI), determined as weight/height2, was used as a measure of fatness. The BMI Z scores were calculated for each patient from standard tables. The ALL group was compared with a control group of 18 age matched children who had received chemotherapy but no radiotherapy. Changes in BMI between diagnosis and two and four years later were analysed by paired t tests. Mean BMI Z scores at diagnosis were similar between ALL boys, ALL girls, and the control group. Two years after diagnosis the ALL group, particularly the girls, showed a significant increase in BMI. By four years BMI had decreased slightly in the ALL boys, but had increased still further in the ALL girls with 57% having BMI Z scores greater than 2. In the control group BMI increased, but not significantly, at two and four years. It is concluded that the obesity seen in patients treated for ALL is more pronounced in girls than boys, and that cranial irradiation is an important factor. (Arch Dis Child 1994; 71: 147-149) Royal Hospital for Sick Children, Yorkhill, Glasgow G3 8SJ I Odame J J Reilly B E S Gibson M D C Donaldson Correspondence to: Dr Donaldson. Accepted 18 April 1994 Acute lymphoblastic leukaemia (ALL) is the most common childhood malignancy, affecting about one in 3500 children under 10 years in the United Kingdom.' With current Medical Research Council (MRC) chemotherapy regimens, it is expected that 65-70% of affected children will achieve long term survival.2 Improved survival rates have focused attention on late effects including cardiotoxicity,3 educational and psychological dysfunction,4 secondary malignancy,5 and disorders of growth and puberty.6 The well documented effects of leukaemia treatment on linear growth and puberty relate largely to the dose of cranial irradiation received. Doses of 2400-2500 cGy cause growth hormone deficiency,7 often with reasonable growth during childhood,8 but attenuation of the pubertal growth spurt.9 Girls show a strong tendency towards precocious and early puberty. 10 Cranial irradiation with 1800 cGy is associated with normal spontaneous growth hormone secretion in prepubertal subjects, but reduced secretion with an abnormal pattern at puberty. 1' The prevalence of obesity in children treated for ALL is less well documented. Zee and Chen, in a large retrospective study of ALL survivors, confirmed the impression that ALL survivors tend to be overweight.'2 Their group were heterogenous in terms of treatment regimen, however, had mostly received 2400 cGy for cranial treatment, and the obesity patterns in girls and boys were not examined separately. Moreover, normal data for body mass index (BMI) in children under the age of 6 years were unavailable at the time of their study. The aim of our study was to examine a group ofALL survivors in first remission, who had received cranial irradiation at 1800 cGy according to UKALL VIII or X protocols, to look specifically for sex differences, and to compare the patterns of obesity with a control group who had received chemotherapy for a range of other malignant disorders, but no radiotherapy.