Nutritional Determinants of Oral Cancer: A Global Population Attributable Fraction Analysis Across 185 Countries (1990–2018)

BACKGROUND: Oral cancer causes approximately 390,000 new cases and 188,000 deaths annually, with substantial functional impairment affecting quality of life. Although dietary associations have been recognised, the nutrition-attributable burden at the population level remains inadequately quantified globally, particularly regarding age-, sex- and region-specific patterns. METHODS: We estimated population attributable fractions (PAFs) for 7 nutritional determinants across 185 countries from 1990 to 2018 using the Global Dietary Database and Global Burden of Disease data. A comparative risk assessment methodology with log-linear dose-response models quantified disease burden attributable to suboptimal dietary intake. Stratified analyses examined sex-specific, age-specific and regional variations. Sensitivity analyses were conducted using relative risk variation analysis, model specification comparison and bootstrap uncertainty analysis. RESULTS: In 2018, fruits (-39.0%), vegetables (-38.8%) and vitamin B9 (-36.5%) exhibited the highest protective PAFs, while sugar-sweetened beverages (+36.1%) demonstrated the greatest harmful impact. The global incidence increased by 56%, despite improvements in protective factors, concurrent with a 37% increase in sugar-sweetened beverage consumption. Males consistently displayed higher PAFs than females across most nutrients (fruits: P = .004; vitamin C: P < .001; processed meats: P < .001), paralleling their 1.9-fold higher global incidence of oral cancer (5.4 vs 2.8 per 100,000). Regional PAF disparities corresponded with cancer-burden patterns: Latin America exhibited the highest sugar-sweetened beverage PAF (+40%) alongside elevated incidence rates (5.5 per 100,000), while South Asia exhibited the greatest vitamin B9 inadequacy (-40%) concurrent with a high regional burden (7.3 per 100,000 in males). Age-gradient analysis revealed that sugar-sweetened beverages disproportionately affected younger age groups (25-29 years: PAF +37.8% vs 75-79 years: PAF +28.9%). However, absolute incidence rates increased with age, reflecting the cumulative nature of cancer risk. Sensitivity analyses confirmed robust estimates (CV: 0.0023-0.0158). CONCLUSIONS: Insufficient intake of fruits (-154.9 g/d), vegetables (-211.9 g/d), vitamin B9 (-449.0 μg/d) and excess sugar-sweetened beverages (+180.1 mL/d) are the predominant modifiable risks. Nonlinear patterns and synergistic interactions suggest the need for multicomponent, region-specific interventions.