Factors Affecting the Increments of Body Mass Index in Adult Survivors of Childhood Brain Tumors

Yoo, Jae Ho; Ahn, Sung Yeon; Shin, Choong Ho; Yang, Sei Won

Abstract

PURPOSE
The purpose of this study was to evaluate the factors affecting the increments of body mass index(BMI) in adult survivors from childhood brain tumors. METHODS: We retrospectively reviewed medical records of 63 patients who were diagnosed with brain tumors and treated at Seoul National University Children's Hospital between 1982 and 2000. We evaluated the factors affecting adult BMI(aBMI) at attainment of final adult height(FAH). Observed factors were as follows : characteristics of tumors, modes of treatment for tumors, existence of growth hormone deficiency(GHD) and growth hormone(GH) replacements, cumulative BMI changes according to GH replacements. RESULTS: aBMI in patients with GHD was greater than that in patients without GHD(23.5+/-3.9 kg/ m2 vs 20.4+/-2.8 kg/m2, P=0.012). Among patients with GHD, GH replacement didn't make any difference in aBMI between treated and untreated patients. Cumulative BMI changes from diagnosis of tumor to attainment of FAH( BMI) were positively correlated with cumulative BMI changes before and during GH replacement(r=0.740, P<0.001 and r=0.574, P<0.001, respectively). When analyzed by multiple stepwise linear regression, the strongest related factor for increment of BMI was the increment of cumulative BMI changes before GH replacements. BMI increments velocity(cumulative BMI change/year) before and during GH replacements were 2.3+/-2.5 kg/m2/year and 0.9+/-1.6 kg/m2/ year, respectively(P=0.005). Patients with extensive surgery were greater aBMI(P=0.036). CONCLUSION: This study suggests that GHD and damage of hypothalamus by tumor and/or modes of treatment contribute to the increment of BMI in adult survivors of childhood brain tumors. Early GH replacements may possibly prevent severe hypothalamic obesity, which should be further clarified.