Cohort study of the total leukocyte count and periodontal disease among company employees.

There have been few epidemiological studies of the relationship between the leukocyte count and dental disease. In the present study, therefore, we investigated the relationship between oral health indicated by the Community Periodontal Index of Treatment Needs (CPITN) and the total leukocyte count in the cohort study. The 1,035 subjects were male factory workers employed at a chemical factory in Osaka, Japan. Their oral conditions were recorded as the CPITN score. The relationship between the total leukocyte count and the oral condition of the subjects classified according to their smoking habits was investigated over a 5-year period. Among the current smokers, the total leukocyte count was highest each year for the group with CPITN level 4, followed by those with CPITN levels 3 and 2 in descending order, showing that the total leukocyte count was reduced as the periodontal diseases ameliorated. Among the nonsmokers, the total leukocyte count was high every year in the group with CPITN levels 4 or 3 compared to that of the group with CPITN level 2. The fluctuations of the total leukocyte count in current smokers and nonsmokers whose CPITN score increase or decreased in five years was investigated. There were no significant differences among the all groups.