Skipping Toothbrushing? Research Suggests It May Lead to Functional Constipation in Kids

"The study found that children who brushed their teeth less frequently had a higher prevalence of constipation than those who maintained regular brushing habits. This association suggests that toothbrushing, a fundamental aspect of self-care, may play a role beyond oral health, potentially influencing digestive function," the researchers wrote.

The researchers note that functional constipation is a common gastrointestinal disorder in childhood, yet its connection to daily habits like toothbrushing remains unclear. Previous research has suggested that oral stimulation, including mastication and toothbrushing, may aid bowel movements, but the association between toothbrushing frequency and functional constipation has not been well established. To explore this link, Masahiro Tsuchiya, Department of Nursing, Tohoku Fukushi University, Aoba-ku, Sendai, Miyagi, Japan, and colleagues analyzed data from 83,660 children, drawn from 104,059 fetal records in the Japan Environment and Children’s Study, an ongoing prospective birth cohort.

Using the ROME III diagnostic criteria, the study examined how daily toothbrushing frequency influences the prevalence of functional constipation in children. After applying multiple imputations to data obtained from self-reported questionnaires, researchers conducted a multivariable binomial logistic regression analysis, adjusting for various maternal and child-related factors.

The study revealed the following findings:

• There was functional constipation in 12.1% (10,123) of children at 3 years and 10.5% (8,820) at 4 years postpartum.
• Children who brushed their teeth less frequently had a higher likelihood of developing functional constipation.
• Compared to those who brushed twice or more daily, the risk of functional constipation increased as toothbrushing frequency decreased, even after adjusting for factors like feeding habits.
• At 4 years postpartum, children who brushed less than once a day had 1.87 times higher odds of functional constipation.
• Those who brushed less than once a day at 2 years postpartum had 1.62 times higher odds of developing chronic functional constipation at both 3 and 4 years postpartum.

The researchers found that lower daily toothbrushing frequency was linked to a higher prevalence of functional constipation in children.

"While the exact mechanism behind this association remains unclear, regular toothbrushing is a key aspect of self-care in children. Our findings suggest that maintaining consistent oral hygiene habits may play a role in managing functional constipation, highlighting the broader impact of daily routines on overall health," they concluded.

Reference:

Tsuchiya, M., Tsuchiya, S., Momma, H., Nagatomi, R., Yaegashi, N., Arima, T., Ota, C., Igarashi, K., & Miura, Y. (2025). Prospective association of daily toothbrushing frequency and the prevalence of childhood functional constipation: The Japan Environment and Children’s Study. Scientific Reports, 15(1), 1-8. https://doi.org/10.1038/s41598-025-88562-8