Oral Microbiome Diversity Links to Longer Sleep, With Marie-Rachelle Narcisse, PhD

At SLEEP 2025, the 39th annual meeting of the Associated Professional Sleep Societies, in Seattle, Marie-Rachelle Narcisse, PhD, an assistant professor of psychiatry and human behavior at the Warren Alpert Medical School of Brown University, presented on a study that found greater oral microbiome diversity was associated with long sleep duration in teenagers and young adults. HCPLive spoke with Narcisse at the meeting about the relationship between oral microbiome diversity and long sleep in 13332 US teenagers and young adults aged 16 – 26 years.

In the first half of this interview, Narcisse discussed why this relationship in teens and young adults may impact early-life health trajectories. She explained that knowing sleep influences microbiome patterns could prevent the development of several chronic diseases, such as obesity, diabetes, and mental health disorders. The greater oral microbiome diversity in patients with long sleep duration) was demonstrated by the following measures: operational taxonomic units (43.0; 95% confidence interval [CI], 22.3 – 63.72), Faith’s phylogenetic diversity (2.96; 95% CI, 1.16 – 4.76), and Shannon-Weiner index (0.64; 95% CI, 0.07 – 1.21).

In this Q&A, Narcisse addressed the unclear directionality of this association, how inflammation, immune activity, or oral disease mediate this relationship, and what longitudinal or interventional studies are needed to explore whether modifying oral microbiota could serve as a therapeutic target for sleep health.

HCPLive: While your study shows association, the directionality remains unclear. Do you think longer sleep enhances oral microbiome diversity, or does a more diverse oral microbiome promote restorative sleep?

Narcisse: At this stage, we can’t say which comes first. This was a cross-sectional study — meaning it was designed to detect associations, not causation. Regardless of the causal direction between oral microbiome and sleep disorders, oral microbiome diversity may serve as a potential easy access way to monitor sleep disorders. Determining the direction of this association will require carefully designed longitudinal and mechanistic studies. For now, we view this as a promising link worth deeper exploration.

HCPLive: How does inflammation, immune activity, or oral disease mediate this relationship, particularly during adolescence, a critical period for both microbiome development and circadian regulation?

Narcisse: Although our study was not designed to test biological mediation, previous research suggests a strong link between inflammation, immune signaling, and changes in both sleep and the microbiome. For example, inflammatory conditions like gingivitis, common in youth, are known to alter the oral microbiome and trigger systemic cytokine release. These immune responses can interfere with circadian rhythms and sleep architecture.

Adolescents are especially sensitive to such disruptions due to hormonal changes. Therefore, inflammation may be a key mediator in this sleep–microbiome relationship, though more targeted research is needed.

HCPLive: What are the potential clinical or preventative implications that should prompt sleep specialists or pediatricians to begin thinking about oral health and microbiome diversity in the context of sleep counseling?

Narcisse: Oral health is a window into whole-body health. The oral microbiome diversity could serve as a low-cost, noninvasive marker for monitoring sleep health — particularly in adolescents and young adults.

A simple salivary microbiome profile might one day inform sleep assessments or identify youth at risk for sleep-related conditions. Promoting healthy sleep and oral hygiene together may offer synergistic benefits, especially during formative years.

HCPLive: What kinds of longitudinal or interventional studies are needed to explore whether modifying oral microbiota could serve as a therapeutic target for sleep health?

Narcisse: Future research should begin with longitudinal studies to track how changes in sleep patterns affect oral microbiota over time and vice versa. These should include larger, more diverse cohorts to ensure generalizability.

Before interventional studies, the direction of causality will need to be determined, and if oral microbial dysbiosis causes sleep disorders, then improving overall oral /dental hygiene will help alleviate the sleep disorders. Intervention trials (e.g., improving oral hygiene, or modulating oral microbiota with probiotics) to observe the impact on sleep outcomes. Such studies could open new, non-invasive paths for supporting sleep health in youth.

References

Marie-Rachelle Narcisse, David Barker, Tsute Chen, Evangelia Morou, Kiara Medeiros, Mary Carskadon, 0360 Associations of Sleep and Oral Microbiome Among Adolescents and Young Adults in the United States, Sleep, Volume 48, Issue Supplement_1, May 2025, Page A157, https://doi.org/10.1093/sleep/zsaf090.0360