Warren Alpert Medical School of Brown University.

Marie-Rachelle Narcisse, PhD

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 

 duration in teenagers and young adults. 

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.

 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?

: 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.

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

: 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.

 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?

: 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.

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

: 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.

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, 

, Volume 48, Issue Supplement_1, May 2025, Page A157, 

https://doi.org/10.1093/sleep/zsaf090.0360

Articles

Research presented at SLEEP 2025 highlights a study linking greater oral microbiome diversity with longer sleep duration in teenagers and young adults. The study, involving 13,332 participants aged 16-26, suggests that understanding this relationship could influence early-life health trajectories and potentially prevent chronic diseases. While the study shows an association, the directionality remains unclear, necessitating further longitudinal and mechanistic studies. The potential for oral microbiota as a therapeutic target for sleep health is discussed, with future research needed to explore causality and interventional strategies.

In this Q&A, Narcisse shared what the association between greater oral microbiome diversity and longer sleep in teens and young adults could mean for early-life disease prevention.

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

Longer Sleep Tied to Oral Microbiome Diversity in Teens, With Marie-Rachelle Narcisse, PhD

A recent study linking oral microbiome diversity with 

 in teenagers and young adults was presented at 

spoke with investigator Marie-Rachelle Narcisse, PhD, an assistant professor of psychiatry and human behavior at the Warren Alpert Medical School of Brown University, on what these findings mean for early-life health trajectories.

“This relationship is important because our microbiome is a key component of the body's immune and metabolic systems,” Narcisse said. “This finding could have implications for preventing chronic diseases that often originate early in life, such as obesity, diabetes, mental health disorders. So, if sleep influences these microbial patterns, this could potentially shape health trajectories for many years to come.”

Evidence has shown that reduced microbial diversity has been associated with chronic physical and mental health conditions, although these studies have mostly been small-scale, focused on the gut microbiome, and involved children or adults. Narcisse and colleagues sought to examine associations of oral microbiome diversity with sleep duration among 1332 US adolescents and young adults.

Using cross-sectional data from the National Health and Nutrition Examination Survey (NHANES, 2011 – 2012), the team collected data on oral microbiome alpha (α) diversity measures of richness and evenness: observed operational taxonomic units (OTU), faith’s phylogenetic diversity (FPD), Shannon-Weiner index (SWI), and Inverse Simpson index (ISI). Sleep exposure variables examined included self-reported sleep hours on weekdays or school/workdays categorized as either very short, short, healthy, or long.

The sample had 50.5% females and a mean age of 20.9 years, with 463 adolescents aged 16 – 18 years and 869 young adults aged 19 – 26 years. Half of the teenagers (5 in 10; 50.6%) reported receiving the recommended hours of sleep (8 – 10 hours), and 6 in 10 young adults (61.2%) reported receiving the recommended hours of sleep (7 – 9 hours).

For the oral microbiome alpha diversity measures, the OUT was 128.0 (95% confidence interval [CI], 122.35 – 133.64), the FPD mean was 14.24 (95%; 13.87 – 14.62), the SWI mean was 4.61 (95% CI, 4.54 – 4.67), and the ISI mean was 0.90 (95% CI, 0.89 – 0.90).

The analysis showed that compared with those who had a healthy sleep duration, teenagers and young adults with long sleep duration (3%) had signficantly greater oral microbiome diversity, indicated by OUT (43.0; 95% CI, 22.3 – 63.72), FPD (2.96; 95% CI, 1.16 – 4.76), and SWI (0.64; 95% CI, 0.07 – 1.21) metrics. The study found no significant association between ISI and sleep duration. The study ultimately demonstrated that the oral microbiome was positively associated with long sleep duration among teenagers and young adults.

“Using multiple indices will help understand the diversity from different aspects, thus providing a more comprehensive view of microbial diversity,” Narcisse said. “So, what could this mean? It could mean that longer sleep may be associated with a more diverse and phylogenetically broad microbial environment, rather than just changes in the most abundant species. Using multiple metrics gives clinicians a more nuanced understanding of microbial health."

Narcisse has no relevant reported disclosures.

Videos

At SLEEP 2025, HCPLive spoke with Narcisse about NHANES-based findings suggesting longer sleep duration is associated with richer and more diverse oral microbiomes.