Number of teeth is associated with all-cause and disease-specific mortality

Background Tooth loss has been shown to correlate with multiple systemic comorbidities. However, the associations between the number of remaining natural teeth (NoT) and all-cause mortality have not been explored extensively. We aimed to investigate whether having fewer NoT imposes a higher risk in mortality. We tested such hypotheses using three groups of NoT (20-28,10-19, and 0-9), edentulism and without functional dentition (NoT < 19). Methods The National Health and Nutrition Examination Survey in the United States (NHANES) (1999-2014) conducted dental examinations and provided linkage of mortality data. NHANES participants aged 20 years and older, without missing information of dental examination, age, gender, race, education, income, body-mass-index, smoking, physical activities, and existing systemic conditions [hypertension, total cardiovascular disease, diabetes, and stroke (N = 33,071; death = 3978), or with femoral neck bone mineral density measurement (N = 13,131; death = 1091)] were analyzed. Cox proportional hazard survival analyses were used to investigate risks of all-cause, heart disease, diabetes and cancer mortality associated with NoT in 3 groups, edentulism, or without functional dentition. Results Participants having fewer number of teeth had higher all-cause and disease-specific mortality. In fully-adjusted models, participants with NoT0-9 had the highest hazard ratio (HR) for all-cause mortality [HR(95%CI) = 1.46(1.25-1.71); p < .001], mortality from heart diseases [HR(95%CI) = 1.92(1.33-2.77); p < .001], from diabetes [HR(95%CI) = 1.67(1.05-2.66); p = 0.03], or cancer-related mortality [HR(95%CI) = 1.80(1.34-2.43); p < .001]. Risks for all-cause mortality were also higher among the edentulous [HR(95%CI) = 1.35(1.17-1.57); p < .001] or those without functional dentition [HR(95%CI) = 1.34(1.17-1.55); p < .001]. Conclusions Having fewer NoT were associated with higher risks for all-cause mortality. More research is needed to explore possible biological implications and validate our findings.