Inflammatory potential of the diet and association with risk of differentiated thyroid cancer in the European Prospective Investigation into Cancer and Nutrition (EPIC) cohort

Purpose: Chronic inflammation is thought to initiate or promote differentiated thyroid cancer (DTC) and previous studies have shown that diet can modulate this inflammatory process. We aimed to evaluate the association of several dietary scores reflecting the inflammatory potential of the diet with DTC risk. Methods: Within the EPIC cohort, 450,063 participants were followed during a mean period of 14 years, and 712 newly incident DTC cases were identified. Associations between four dietary inflammatory scores [the dietary inflammatory index (DII^®) and two energy-adjusted derivatives (the E-DII_r and the E-DII_d), and the Inflammatory Score of the Diet (ISD)] and DTC risk were evaluated in the EPIC cohort using multivariable Cox regression models. Results: Positive associations were observed between DTC risk and the DIIs (HR for 1 SD increase in DII: 1.11, 95%CI: 1.01, 1.23, similar results for its derivatives), but not with the ISD (HR for 1 SD increase: 1.04, 95% CI 0.93, 1.16). Conclusion: Diet-associated inflammation, as estimated by the DII and its derivatives, was weakly positively associated with DTC risk in a European adult population. These results suggesting that diet-associated inflammation acts in the etiology of DTC need to be validated in independent studies.