Objective: The purpose was to study the growth of lactobacilli in subjects with depressive symptoms in the total 55-year-old population of Oulu (a medium-sized town in Finland); 780 people participated.
Methods: The dental examination included measurements of salivary lactobacillus growth with the Dentocult-LB method; measurements of salivary flow rate, pH, and buffering capacity; and assessment of oral health status. Depressive symptoms were determined with the Zung Self-Rating Depression Scale (ZSDS). Participants were also asked about their health, medication, smoking, and dietary habits.
Results: The prevalence of high lactobacillus counts (> or =100,000 CFU/ml) was 22% among women and 31% among men (p = .02). Thirty-seven percent of the subjects with a high rate of depressive symptoms (ZSDS score of > or = 40) and 23% of those with an ZSDS score of < or = 39 had high counts of lactobacilli (p = .003). A logistic regression analysis with improvement of goodness of fit was made to confirm the relation between abundant lactobacilli and a high rate of depressive symptoms. After the confounding factors had been added stepwise into the logistic regression model, depressive symptoms were still significantly associated with abundant lactobacillus growth.
Conclusions: The association between high lactobacillus counts and depressive symptoms suggests that depressed subjects are at risk of having caries and possibly other dental diseases that should be recognized in the treatment of these patients.