Inflammation is implicated in chronic diseases including cancer and cardiovascular diseases (CVD), which are major causes of mortality. Diet can influence inflammation status. We therefore examined whether the inflammatory potential of a person’s diet is associated with mortality.

Inflammatory potential of usual diet was assessed by calculating dietary inflammatory index (DII) scores from repeated food frequency (FFQ) data (collected in 1992, 1994, 1996), placing each participant’s diet on a continuum from anti- to pro-inflammatory. DII scores were analysed as a continuous variable and as categories by creating quartile groups. Death registry data were used to ascertain all-cause mortality and separately mortality from CVD, cancers, and other causes between 1992-2022. Cox proportional hazards regression analysis was used to calculate adjusted hazard ratios (HRs) with 95% confidence intervals (CIs), comparing higher vs. lowest quartile groups, or HR change per one DII-unit increase.

Nambour, Australia

A community-based sample of 1440 adults aged 25-75 years

During follow-up, 488 participants died, including 188 from CVD, 151 from cancer, and 170 from other causes. Participants in the most pro-inflammatory diet group were at increased risk of all-cause mortality (HRQ4vsQ1 = 1.55; 95% CI 1.19, 2.03; P trend < 0.001), and other-cause mortality (HRQ4vsQ1 = 1.69; 95% CI 1.12, 2.54; P trend 0.01). A one-unit increase in DII-score was associated with a 36% increased risk of CVD among those younger than 55 years of age (HR for a one-unit increase in DII score: 1.36, 95% CI: 1.04-1.78). The risk of cancer mortality was also increased for those with a more pro-inflammatory diet in age ≤55yr: HR for a one-unit increase in DII score: 1.20, 95% CI: 1.02-1.40, and age 56-65yr: HR for a one-unit increase in DII score: 1.11, 95 % CI: 1.00-1.23).

A pro-inflammatory diet increases the risk of all-cause mortality. Our results support promotion of anti-inflammatory diets to help promote longevity.