Association Between a Dietary Inflammatory Index and Prostate Cancer Risk in Ontario, Canada

Evidence exists showing that various aspects of diet are implicated in the etiology of prostate cancer, although results across studies remain inconsistent.

We examined the ability of the dietary inflammatory index (DII) to predict prostate cancer in a case-control study conducted in Kingston, Ontario, Canada, between 1997 and 1999. The study included 72 cases of incident primary prostate cancer patients and 302 controls of urology clinic patients who had prostate conditions other than prostate cancer. The DII was computed based on intake of 18 nutrients assessed using a 67-item food frequency questionnaire. Univariate and multivariate logistic regression models were used to estimate odds ratios (ORs).

Men with higher DII scores were at increased risk of prostate cancer using DII score fit both as a continuous [OR = 1.58, 95% confidence interval (CI) 1.05-2.38] and categorical variable [compared to men in the lowest DII quartile, men in the highest quartile were at elevated risk (OR = 3.50, 95% CI 1.25-9.80; p_trend = 0.02)]. There was no significant heterogeneity by weight status, but stronger association was observed in men with body mass index >25 kg/m² versus <25 kg/m².

These findings suggest that a proinflammatory diet, as indicated by increasing DII score, is a risk factor for prostate cancer.