Are there age-dependent effects of diet on prostate cancer risk?

Objectives. To examine whether there are age-dependent effects of diet on p rostate cancer risk. Methods: We have postulated that nutritional factors that may affect the ri sk of initiation would be more likely to be identified among younger patien ts, whereas those that may affect the risk of progression would be more cle arly identifiable among older patients. Study subjects were 320 patients wi th prostate cancer and 246 controls with no systematic disease, hospitalise d in six major hospitals in Athens, Greece. Logistic regression models were fitted separately for men under 70 years and 70 years or older. Results: Polyunsaturated lipids substantially increased the risk among youn ger subjects, but played little role among older ones (p for interaction 0. 21). Cooked tomatoes had a strong protective effect among older persons, bu t not among younger subjects (p for interaction 0.009). Last, vitamin E was strongly inversely related to prostate cancer risk among younger subjects, but not among older subjects (p for interaction 0.15). Conclusions: Even a simple straight forward interpretation of the data, i.e ., that older cases of prostate cancer have a different dietary risk profil e than younger ones, has potentially useful implications.