A Population-Based Study of the Association Among Dry Mouth, Vitamin B2, and Mortality

Background: Previous studies have indicated that older adults with the symptom of dry mouth have an increased risk of death. B vitamins are strongly linked to oral and systemic health. However, the relationship among dry mouth, vitamin B2 and mortality remains unclear. Objectives: This study aimed to investigate the potential relationship among dry mouth, vitamin B2 and mortality. Methods: A total of 6183 participants from the US National Health and Nutrition Examination Survey (NHANES) 2011–2014 with information on dry mouth were included at baseline. 4324 normal individuals and 684 individuals with dry mouth were followed up until 31 December 2019. The Cox proportional hazard model was used to estimate the hazard ratios (HRs) and 95% confidence intervals (CIs) for the associations among dry mouth, vitamin B2 and all-cause mortality. Results: Compared to the population without dry mouth, the risk of all-cause mortality was significantly higher in the population with dry mouth. The multivariable-adjusted HR and 95% CI was 1.41 (1.05, 1.90). The intake of vitamin B2 can significantly reduce the risk of death in participants with dry mouth, but not in participants without dry mouth. The HR and 95% CI of all-cause mortality in the highest vitamin B2 intake group was 0.37 (0.19, 0.73) compared to the lowest intake group. Conclusions: Individuals with dry mouth suffered a significantly higher risk of all-cause mortality compared to those without dry mouth. Higher intake of vitamin B2 was apparently associated with a lower risk of all-cause mortality in the population with dry mouth.