Association between a combined lifestyle exposure index and age at pancreatic cancer diagnosis: a hospital-based retrospective study
Pancreatic cancer is a highly lethal malignancy, and its incidence is increasing among younger individuals. Although smoking, alcohol use, and unhealthy diet are established risk factors, the cumulative impact of multiple lifestyle exposures on age at diagnosis remains unclear. This study aimed to estimate the combined burden of lifestyle and environmental risks associated with the timing of pancreatic cancer diagnosis. We conducted a hospital-based retrospective case-only study including 134 patients diagnosed with pancreatic cancer between 2020 and 2025. Data on family history of pancreatic cancer, cigarette smoking, alcohol consumption, dietary patterns, exercise, and occupational chemical exposure were collected through structured interviews and medical record reviews. Cox proportional hazards models using age at diagnosis as the time scale were used to evaluate associations between exposures and earlier diagnosis. Lifestyle factors were integrated into a cumulative exposure index and analyzed using Cox models with adjustment for the remaining covariates. The mean age at diagnosis was 64.8 years. A significant difference in age at diagnosis was observed across smoking categories, with current smokers having the youngest mean age, whereas no significant difference was observed across alcohol consumption categories. Patients with triple exposure had the youngest mean age at diagnosis (55.5 years), followed by those with double (63.5 years), single (64.8 years), and no (69.0 years) exposures. Compared with no exposure, single, double, and triple exposures were associated with progressively higher hazards of earlier diagnosis (HR = 1.79, 95% CI: 1.14–2.81, p = 0.011; HR = 2.97, 95% CI: 1.67–5.28, p < 0.001; and HR = 6.66, 95% CI: 3.35–13.22, p < 0.001, respectively). Our findings indicate a significant association between a higher combined exposure index and earlier age at pancreatic cancer diagnosis. This exposure–response gradient suggests that a greater accumulation of adverse lifestyle exposures corresponds to earlier age at diagnosis among affected patients. Not applicable.