LB14

The association between diet and serum concentrations of IGF-I and IGFBP-1, -2 and -3 in the European Prospective Investigation of Cancer and Nutrition (EPIC)

Francesca Crowe, Tim Key, Naomi Allen, Paul Appleby, Andrew Roddam

Cancer Epidemiology Unit, University of Oxford, UK

Background
Circulating concentrations of insulin-like growth factor I (IGF-I) and insulin-like growth factor binding proteins (IGFBPs) have been associated with the risk of several types of cancer. Dietary correlates of IGF-I and IGFBPs are not yet well established. The objective of this study was to assess the association between dietary intake, in particular various sources of protein, and serum concentrations of IGF-I, IGFBP-1, IGFBP-2 and IGFBP-3.

Method
This analysis included 4731 men and women from Denmark, France, Germany, Greece, Italy, the Netherlands, Norway, Spain and the UK who were participating in the European Prospective Investigation into Cancer and Nutrition (EPIC). Diet was assessed using country-specific validated dietary questionnaires. Serum concentrations of IGF-I, IGFBP-1, IGFBP-2 and IGFBP-3 were measured and the associations between dietary components and insulin-like growth factors were assessed by using multiple linear regression adjusting for sex, age at blood collection, body mass index, smoking status, alcohol consumption and total energy intake.

Results
Each 1 standard deviation increment in the intakes of total and dairy protein, and calcium were associated with an increase in IGF-I concentration of 2.5%, 2.4% and 3.3%, respectively (Ptrend for all < 0.001) and a decrease in IGFBP-2 of 3.5%, 3.5% and 5.4%, respectively (P trend for all < 0.001). There were no significant associations between the intake of protein or calcium from sources other than dairy products and the concentrations of any of the insulin-like growth factors.

Conclusion
The results from this large cross-sectional analysis indicate that either the intake of dairy protein or calcium is an important dietary determinant of IGF-I and IGFBP-2 concentrations; however, we would suggest that it is more likely to be protein from dairy products.