In the Norwegian Women and Cancer study (NOWAC), detailed dietary information is available in addition to a large biobank. Altogether 68 000 women aged 41-70 years at recruitment have been followed up for cancer incidence and mortality through linkages to national registers based on the unique national birth number. The biobank will by mid 2006 consist of samples from 50 000 women. These samples will be available for whole genome expression analysis (buffered mRNA), analysis of traditional- and emerging c ontaminants, poly-unsaturated fatty acids (PUFA), vitamin D, and buffy coat for DNA or single nucleotide analysis. We have started the analysis of about 400 samples for PUFA, and will go on with the analysis of contaminants and vitamin D in order to do a cross-sectional study on the effect of contaminants and diet on gene expression. The results from the biochemical analysis will be used as a validation of the estimated intake of contaminants from food in the questionnaire database. The estimated figure w ill then be used in the follow-up analysis of the total NOWAC cohort. In order to improve our basic knowledge of the metabolism of these compounds we will compare the levels of contaminants and selected nutrients with the gene expression pattern based on a micro-array test of more than 30 000 genes. In a case-control design, dioxin-like effects we will be investigated using an in vitro study. DR CALUX methods will be employed, due to the low sample volume in the bio-bank. Based on statistical power estima tes, relative risk of 1.15 and 1.25 for effects of fatty fish consumption on breast- and colon-rectal cancer, respectively, can be detected.
Using this interdisciplinary approach in the national representative NOWAC study, we should be able to do an over all risk assessment of intake of food from the sea.