This cross-sectional study found that objectively measured halitosis was prevalent in 40.3% of university students but was not significantly associated with tongue coating, sleep quality, or symptoms of anxiety, depression, and stress, though tongue-cleaning habits and oral mucosal desquamation were significantly associated with halitosis presence.
Key Findings
Results
Objectively measured halitosis was identified in 40.3% of university students.
25 out of 62 participants were identified as having halitosis.
95% confidence interval: 29.0–52.7%.
Halitosis was assessed using a portable breath detector.
Participants were Brazilian university students enrolled in health-related undergraduate programs in the metropolitan region of Santos, Brazil.
Most participants were in their first academic year (61.3%) and resided in the municipality of Santos (59.7%).
Results
No statistically significant associations were found between objectively measured halitosis and tongue coating, sleep quality, or psychological symptoms.
Tongue coating was evaluated using the Coated Tongue Index.
Sleep quality was assessed using the Pittsburgh Sleep Quality Index (PSQI).
Psychological symptoms were measured using the Depression, Anxiety and Stress Scale (DASS-21).
The analyses did not provide statistically significant evidence of associations between halitosis and any of these factors.
The authors note these findings highlight the importance of objectively assessing oral malodor in epidemiological studies.
Results
Tongue-cleaning habits were significantly associated with the presence of halitosis.
Participants with halitosis differed significantly from those without halitosis with respect to tongue-cleaning habits.
This was one of two behavioral/clinical variables found to be significantly associated with halitosis in this sample.
The study design was cross-sectional, so causality cannot be inferred.
Results
Oral mucosal desquamation was significantly less frequent among participants with halitosis.
Participants with halitosis had lower rates of oral mucosal desquamation compared to those without halitosis.
This finding was statistically significant.
This was identified as one of two clinical variables significantly associated with halitosis presence.
Results
Significant positive correlations were identified between stress and sleep disturbance, and between anxiety and sleep disturbance.
These correlations were identified independently of halitosis status.
Both stress and anxiety showed significant positive correlations specifically with the sleep disturbance component of the PSQI.
These associations were measured using the DASS-21 and PSQI instruments.
Results
Depression was significantly positively correlated with sleep latency, daytime dysfunction, and overall sleep quality.
Depression scores on the DASS-21 were significantly associated with three PSQI components: sleep latency, daytime dysfunction, and overall sleep quality.
These associations were found in the full sample of 62 university students.
The study was cross-sectional, precluding causal interpretation.
What This Means
This research suggests that bad breath (halitosis) is quite common among university students, affecting about 4 in 10 participants in this Brazilian sample. Despite concerns that halitosis might be linked to poor sleep or mental health struggles such as anxiety, depression, and stress, the study found no statistically significant connections between objectively measured bad breath and these psychological or sleep-related factors. The one clear behavioral finding was that tongue-cleaning habits were related to whether or not a student had halitosis, suggesting that oral hygiene practices may play a practical role in managing bad breath.
The study also found that among university students, stress and anxiety were linked to sleep disturbances, and depression was associated with taking longer to fall asleep, experiencing daytime dysfunction, and poorer overall sleep quality. These findings are independent of halitosis and point to a broader pattern in which psychological well-being is intertwined with sleep health in this population.
One important takeaway from this research is the value of using objective measurement tools—like a portable breath detector—rather than relying on self-reports when studying halitosis. This matters because people are often unaware of their own bad breath, and self-reported studies may miss a significant portion of those affected. The authors suggest that future epidemiological research on oral malodor should use objective assessment methods to get more accurate results.
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Gallo J, Mandetta A, Sobral A, Gonçalves M, Costa M, Ribeiro C, et al.. (2026). Halitosis and Its Association with Sleep Quality and Psychological Factors Among University Students: A Cross-Sectional Study.. International journal of environmental research and public health. https://doi.org/10.3390/ijerph23081043