BACKGROUND: We reported that human T cell leukemia virus 1 (HTLV-1) infection is positively associated with atherosclerosis. Recent evidence has revealed a close association of periodontitis with atherosclerosis, endothelial dysfunction, and disruption of the microcirculation. However, the association between HTLV-1 and advanced periodontitis has not been investigated to date. Since hematopoietic activity is closely linked to endothelial maintenance activity and is known to decline with age, we hypothesized that the state of hematopoietic activity influenced the association between HTLV-1 and advanced periodontitis in elderly participants. METHODS: A cross-sectional study was performed including 822 elderly participants aged 60-99 years who participated in a dental health check-up. Advanced periodontitis was defined as a periodontal pocket ≥ 6.0 mm. Participants were classified as having low or high hematopoietic activity according to the median values of reticulocytes. RESULTS: HTLV-1 infection was positively related to advanced periodontitis among participants with lower hematopoietic activity (lower reticulocyte count), but not among participants with higher hematopoietic activity (higher reticulocyte count). The adjusted odds ratio (95% confidence interval) considering potential confounding factors was 1.92 (1.05-3.49) for participants with a lower reticulocyte count and 0.69 (0.35-1.36) for participants with a higher reticulocyte count. CONCLUSIONS Among elderly participants, the association between HTLV-1 infection and advanced periodontitis is influenced by hematopoietic activity. Since hematopoietic activity is associated with endothelial maintenance, these findings provide an efficient tool for clarifying the underlying mechanism of the progression of periodontitis among elderly participants.
Aged ; Aged, 80 and over ; Cross-Sectional Studies ; Female ; HTLV-I Infections ; physiopathology ; Hematopoiesis ; physiology ; Human T-lymphotropic virus 1 ; physiology ; Humans ; Japan ; epidemiology ; Male ; Middle Aged ; Odds Ratio ; Periodontitis ; epidemiology ; virology ; Prevalence ; Risk Factors

BACKGROUND: Human T cell leukemia virus type-1 (HTLV-1) stimulates inflammation activity. Our previous study revealed a positive association between asymptomatic HTLV-1 infection and advanced periodontitis among elderly Japanese individuals with low levels of hematopoietic activity (reflected by reticulocyte levels). Since low hematopoietic activity has been correlated with low-grade inflammation and low-grade inflammation is associated with atherosclerosis, the status of atherosclerosis could, in turn, determine the nature of this association. METHODS: To this end, a cross-sectional study of 907 elderly Japanese individuals (aged 60-99 years), who had participated in dental health check-up during the period 2016-2018, was conducted. Advanced periodontitis was defined as periodontal pocket ≥ 6.0 mm. RESULTS: Among the study population, 295 (32.5%) were found to have atherosclerosis defined as a carotid intima-media thickness (CIMT) of ≥ 1.1 mm. HTLV-1 infection was positively associated with advanced periodontitis in participants with atherosclerosis, but no significant associations were observed among the participants without atherosclerosis. The known risk factors' (including reticulocyte and CIMT) adjusted odds ratio (OR) and 95% confidence interval (CI) of advanced periodontitis were OR 2.01 and 95% CI 1.06-3.81 for participants with atherosclerosis and OR 0.61 and 95% CI 0.34-1.12 for participants without atherosclerosis. CONCLUSION This study found a significant association between HTLV-1 infection and advanced periodontitis among elderly Japanese with atherosclerosis. However, this association is absent in individuals without atherosclerosis, suggesting that atherosclerosis might act as a determinant in the association between HTLV-1 infection and advanced periodontitis among elderly Japanese.