Importance: The incidence of oral cavity cancer (OCC) is increasing among nonsmokers and young individuals without traditional risk factors worldwide. High sugar-sweetened beverage (SSB) intake is associated with various gastrointestinal cancers, but its association with OCC has not been explored.

Objective: To evaluate the association between SSB intake and the risk of OCC among smoking and nonsmoking women participating in the Nurses' Health Study (NHS) and Nurses' Health Study II (NHSII).

Design, setting, and participants: This longitudinal cohort study analyzed data from women in the NHS (follow-up, 1986-2016) and NHSII (follow-up, 1991-2017) after excluding those with a history of cancer, implausible caloric intake, or missing SSB intake data. Participants were followed up until the diagnosis of OCC. Data analysis was performed from July 2023 to June 2024.

Exposure: SSB intake, quantified by frequency of consumption ranging from less than 1 SSB monthly to 1 or more SSBs daily.

Main outcome and measure: Cox proportional hazards regression models with age and questionnaire period as the time scale were used to estimate hazard ratios (HRs) and 95% CIs associated with the development of OCC for each category of SSB intake, with less than 1 SSB per month as the reference group.

Results: A total of 162 602 women (mean [SD] age, 43.0 [9.9] years) were evaluated. During 30 years of follow-up, 124 invasive OCC cases were documented. In multivariable-adjusted models, participants consuming 1 or more SSB daily (5 people per 100 000 population) had a 4.87 times (95% CI, 2.47-9.60 times) higher risk of OCC compared with those consuming less than 1 SSB monthly (2 people per 100 000 population), increasing the rate of OCC to 3 more people per 100 000 population. When restricted to both nonsmokers or light smokers and nondrinkers or light drinkers, the risk of OCC was 5.46 times (95% CI, 1.75-17.07 times) higher, increasing the rate of OCC to 3 more people per 100 000 population.

Conclusions and relevance: In this study, high SSB intake was associated with a significantly increased risk of OCC in women, regardless of smoking or drinking habits, yet with low baseline risk. Additional studies are needed in larger cohorts, including males, to validate the impact of these findings.