Are dietary influences on the risk of prostate cancer mediated through theinsulin-like growth factor system?

Objectives To investigate whether dietary factors that appear to affect the risk of prostate cancer may be similarly associated with serum levels of i nsulin-like growth factor 1 (IGF-1). Patients and methods In the context of a case-control study, 112 men were a dmitted to three teaching hospitals in Athens, Greece, for disorders other than cancer. Sociodemographic data and detailed histories of smelting, alco hol and coffee consumption were recorded. A validated food-frequency questi onnaire was administered by an interviewer and serological measurements of IGF-1 and its binding protein-3 conducted. Results IGF-1 declined significantly by almost 25% among men aged > 75 year s and there was a small reduction in IGF-1 levels with increased alcohol in take, with a mean (95% confidence interval, CI) change of -1.6 (-2.2 to -0. 9)% for an increment of one drink per day, There was no evidence for an eff ect of either smelting or coffee consumption on IGF-1 level. Among foods, t he consumption of cooked tomatoes was substantially and significantly inver sely associated with IGF-1 levels, with a mean (95% CI) change of -31.5 (-4 3.1 to -7.9)% for an increment of one serving per day. Conclusions The strongest known dietary risk factor for prostate cancer (ly copene deficit, as reflected in a reduced intake of cooked tomatoes) and an important endocrine factor in the aetiology of this disease (IGF-1) seem t o be related in a way that suggests that at least one, and perhaps more, ex ogenous factors in the development of prostate cancer may be mediated throu gh the IGF-1 system.