An interesting article titled “Association between sleep duration and dental caries in a nationally representative U.S. population” written by Abdullah Alawady and et. al. appears in BMC Oral Health (vol. 23, Article number 497, 2023). The article seeks to establish the relationship between sleep duration and dental caries (cavities).
The authors used data from the 2017-2018 U.S. National Health and Nutrition Examination Survey to explore 5,205 patients age 16 and older who completed a dental exam and sleep questionnaire. They performed regression analyses to reveal a statistically significant negative relationship between caries and sleep duration. It was found that those who have an average sleep duration of seven or more hours per night were less likely to have caries compared to people who slept less than seven hours (95% confidence interval 0.33 to 0.82; p < 0.05). Specifically 88.9% (4630/5205) of the study population had experienced dental caries, and 92.5% (1080/1167) of people who reported slept ess than 7 hours had caries, versus 87.9% (3550/4038) who slept ore than 7 hours. The authors found for someone who had a one hour increase in average sleep hours, the Adjusted Mean Ratio of untreated dental caries might decrease by 0.89.
The authors state:
“This study has demonstrated that decreased sleep duration was associated with higher levels of dental caries.”
The authors point out that little other studies exploring such a relationship has been conducted but one study of Kuwaiti children showed that children who go to bed late have increased dental caries incidence when compared to those who go to bed early. Some other studies have shown that sleep behavior can control appetite. In particular, decresed sleep can lead to increased levels of ghrelin, a hormone which increases appetite and a decrease in leptin, a hormone which decreases appetite. Several studies have shown that short sleep duration is associated with higher BMI and obesity. Studies have also shown that insufficient sleep can reduce the salivary flow rate and promote dental caries. Another study has shown that the secretion rate of salivary Immunoglobulin A (IgA), an antibody that has a crucial role in preventing colonization by pathogens, was decreased on a sleep deprived group in comparison to a control group.
Several limitations of the study included the use of self-reported sleep behavior as there could be recall bias. In addition factors that impact dental caries such as
sugar intake, frequency of oral hygiene measures and toothpaste type use were not reported by the U.S. National Health and Nutrition Examination Survey. The authors say that more longitudinal studies should be conducted to explain the underlying biological mechanisms by which too little sleep affects the oral microbiome, oral biomarkers, and pH levels.