Over-the-counter mouthwash use, nitric oxide and hypertension risk.
Level 3 - non-randomized controlled study
Prospective longitudinal cohort study
PubMed 31709856 · doi:10.1080/08037051.2019.1680270
What was done
In the San Juan Overweight Adults Longitudinal Study (SOALS), 540 overweight or obese individuals aged 40–65 years without baseline hypertension were followed prospectively over a 3-year period (2011–2016). The primary exposure was over-the-counter mouthwash use twice daily or more. The primary outcome was self-reported physician-diagnosed incident hypertension. Poisson regression was used, adjusting for age, sex, smoking, physical activity, waist circumference, alcohol intake, baseline systolic blood pressure, prediabetes/diabetes status, and cardiac medication use.
What was found
Over follow-up, 12% (66/540) developed hypertension. Participants using mouthwash twice daily or more had a higher incidence of hypertension compared to less frequent users (Incidence Rate Ratio [IRR] = 1.85; 95% CI: 1.17, 2.94) and compared to non-users (IRR = 2.17; 95% CI: 1.27, 3.71). Associations persisted among never-smokers. Blood pressure assessed at a single study visit did not show significant associations.
Why it matters
Antibacterial mouthwash is known to deplete oral nitrate-reducing bacteria that support systemic nitric oxide bioavailability. This prospective study suggests that frequent routine mouthwash use may be an independent, modifiable risk factor for hypertension.
Limits
The primary outcome relied on self-reported physician diagnoses, while objective blood pressure measured at a single study visit showed no association. The cohort was limited to overweight or obese adults aged 40–65, specific mouthwash types and active ingredients were not differentiated, and residual confounding cannot be ruled out.
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