Insulin-like growth factor-I concentration and risk of prostate cancer: results from the European Prospective Investigation into Cancer and Nutrition
A partir des données de la cohorte européenne "EPIC", cette étude (1 542 cas et 1 542 témoins) évalue l'association entre la concentration du facteur de croissance analogue à l'insuline et le risque de cancer de la prostate
Background High circulating insulin-like growth factor-I (IGF-I) concentrations have been associated with increased risk for prostate cancer in several prospective epidemiological studies. In this study we investigate the association between circulating IGF-I concentration and risk of prostate cancer over the long-term in the European Prospective Investigation into Cancer and Nutrition (EPIC) study. Methods In a nested case-control design, 1,542 incident prostate cancer cases from 8 European countries were individually matched to 1,542 controls by study centre, age at recruitment, duration of follow-up, time of day, and duration of fasting at blood collection. Conditional logistic regression models were used to calculate risk for prostate cancer associated with IGF-I concentration, overall and by various subgroups. Results Circulating IGF-I concentration was associated with a significant increased risk for prostate cancer (odds ratio (OR) for highest vs. lowest quartile 1.69; 95% CI: 1.35-2.13; P trend = 0.0002). This positive association did not differ according to duration of follow-up (ORs for highest vs. lowest quartile were 2.01 (1.35-2.99), 1.37 (0.94-2.00) and 1.80 (1.17-2.77) for cancers diagnosed <4, 4-7 and >7 years after blood collection, respectively (P heterogeneity = 0.77)) or by stage, grade, age at diagnosis or age at blood collection (all subgroups P heterogeneity >0.05). Conclusion In this European population, high circulating IGF-I concentration is positively associated with risk for prostate cancer over the short and long-term. Impact As the only potentially modifiable risk factor so far identified, research into the effects of reducing circulating IGF-I levels on subsequent prostate cancer risk is warranted.