Using convenience sampling method, the study included the students of class 2021 of Jining No. 7 Middle School and student athletes from the Jining Sports Training Center. Univariate and multivariate linear regression analyses were used to investigate the correlation between tooth brushing frequency and blood indicators such as eosinophil percentage (EOS%), eosinophil count (EOS#), basophil percentage (BAS%), basophil count (BAS#), superoxide dismutase (SOD), insulin-like growth factor 1 (IGF-1) and uric acid (UA).

A total of 305 students were included (167 from Jining No. 7 Middle School, 138 from Jining Sports Training Centre), with 192 (62.95%) males and 113 (37.05%) females. They were divided into three groups based on daily teeth brushing frequency: ≤1 time (40.33%, 123/305), 2 times (53.77%, 164/305), and ≥3 times (5.90%, 18/305).Univariate linear regression analysis showed that brushing twice daily was negatively correlated with EOS%, EOS#, BAS%, and BAS#(all β > 0, all P < 0.05), and positively correlated with SOD and IGF-1(both β < 0, P=0.028, P=0.007). Brushing three or more times daily was negatively correlated with UA[β(95% CI): -0.16(-0.27~0.04), P=0.008]. Multivariate linear regression analysis showed that brushing twice daily was negatively correlated with BAS%(β < 0, P=0.042) and positively correlated with SOD and IGF-1(both β > 0, P=0.036, P=0.012), while brushing three or more times daily was negatively correlated with UA(β < 0, P=0.026). Subgroup analysis revealed that in male adolescents, brushing twice daily was positively correlated with IGF-1(β > 0, P=0.044), and in female adolescents, brushing three or more times daily was negatively correlated with UA(β < 0, P=0.014).

The adolescent tooth brushing frequency correlates with several blood indicators affecting general health, suggesting that there may be a potential association between oral health and general health.