Childhood obesity and hormonal abnormalities associated with cancer risk

There is growing evidence that overweight and obesity increase the risk of certain cancers. Studies in adults support the role of insulin-like growth factors (IGFs) and oestrogens in the pathogeneses of several cancers. We propose that hormone alterations described as risk factors for cancer in obese adults are present in prepubertal obese children. A group of obese children aged 6-9 years (n=40), and control group paired for age and sex, were used for the study. The obese children presented a significantly high level of IGF-I (P=0.0173) and insulin (P=0.0250), with a drop in sex hormone-binding globulin (SHBG) (P=0.0282). The 17beta-oestradiol (E-2)/SHBG ratio increase in obese subjects was marginally significant (P=0.0635). Grouping together all the children in quartiles for insulin and body mass index, the upper quartiles showed a rise in IGF-I and E-2/SHBG. In a multivariant correlation analysis, only height (partial r=0.2464) and insulin (partial r=0.3002) were independent prediction variables for IGF-I concentration. The only variables statistically correlated with the E-2/SHBG ratio were insulin (r=0.2879) and IGF-I (r=0.4140). The obese children in our study showed hormone changes described as risk factors for cancer in obese adults. These changes were significantly associated with the hyper-insulinaemia. We hypothesize that this potential risk should be taken into account given the long period of exposure involved in the presence of hormone alterations at such early ages. (C) 2004 Lippincott Williams Wilkins.