Population attributable fraction of dietary risk factors for cancer mortality with a focus on gastrointestinal cancers in a population based cohort study

Diet and nutrition are critical factors influencing cancer, the second leading cause of death worldwide. This study evaluated dietary risk factors and cancer mortality. 49,773 participants aged 40-75 years from the Golestan Cohort Study (GCS) were followed for a median of 15 years. Dietary intake was assessed using a validated food frequency questionnaire. Cox proportional hazard models estimated hazard ratios (HRs) and 95% confidence intervals (CIs), while population attributable fractions (PAFs) quantified the impact of reducing dietary risk factors. Low fruit intake accounted for 4.7% (95% CI: 0.5-8.7%) of all cancer deaths and 4.91% (95% CI: 0-9.85%) of male cancer deaths. It contributed to 23.5% (95% CI: 4.7-38.59%) of pancreatic cancer mortality in both sexes and 29.36% (95% CI: 5.15-47.38%) of male pancreatic cancer deaths. Low omega-3 intake increased esophageal and gastric cancer mortality risks, with PAFs of 21.65% (95% CI: 1.14-37.9%) and 21.46% (95% CI: 2.81-36.53%), respectively. In females, low omega-3 intake accounted for 38.68% (95% CI: 4.05-60.81%) of gastric cancer deaths. Low fruit and omega-3 consumption elevated cancer mortality risk. Community- and individual-level interventions are essential to enhance nutrient intake and reduce cancer mortality.