The Nordic Nutrition Recommendations and prostate cancer risk in the Cancer of the Prostate in Sweden (CAPS) study

Objective: The Nordic Nutrition Recommendations (NNR) aim at preventing diet-associated diseases such as cancer in the Nordic countries. We evaluated adherence to the NNR in relation to prostate cancer (PC) in Swedish men, including potential interaction with a genetic risk score and with lifestyle factors. Design: Population-based case-control study (Cancer of the Prostate in Sweden (CAPS), 2001-2002). Using data from a semi-quantitative FFQ, we created an NNR adherence score and estimated relative risks of PC by unconditional logistic regression. Individual score components were modelled separately and potential modifying effects were assessed on the multiplicative scale. Setting: Four regions in the central and northern parts of Sweden. Subjects: Incident PC patients (n 1386) and population controls (n 940), frequency-matched on age and region. Results: No overall association with PC was found, possibly due to the generally high adherence to the NNR score and its narrow distribution in the study population. Among individual NNR score components, high compared with low intakes of polyunsaturated fat were associated with an increased relative risk of localized PC. No formal interaction with genetic or lifestyle factors was observed, although in stratified analysis a positive association between the NNR and PC was suggested among men with a high genetic risk score but not among men with a medium or low genetic risk score. Conclusions: Our findings do not support an association between NNR adherence and PC. The suggestive interaction with the genetic risk score deserves further investigations in other study populations.