Tooth Loss Trajectories and Their Association with Functional Disability among Older Chinese Adults: Results from the Chinese Longitudinal Healthy Longevity Survey.

BACKGROUND: Tooth loss becomes more prevalent with age and increases risk of functional disability. However, the strength of tooth loss varies between individuals rather than a uniform loss with age. We aimed to evaluate tooth loss trajectories and their association with functional disability among older Chinese adults. METHODS: We included 16,209 participants aged >/=65 years from five waves of the Chinese Longitudinal Healthy Longevity Survey 2002-2014. The number of teeth, Activities of Daily Living (ADL), and Instrumental ADL (IADL) were assessed at baseline and subsequently every three years. ADL disability and IADL disability were defined as needing any help in any item of the Katz scale and a modified Lawton's scale, respectively. A group-based trajectory model was used to determine tooth loss trajectories based on the self-reported number of teeth and generalized estimating equation models were used to explore associations of tooth loss trajectories with ADL disability and IADL disability. RESULTS: This study identified four tooth loss trajectories, including Progressively Mild Loss (14.4%), Progressively Severe Loss (21.5%), Persistently Severe Loss (45.1%), and Edentulism (19.0%) among older Chinese adults. Compared with the Progressively Mild Loss trajectory, the Progressively Severe Loss (ADL disability: OR=1.45, 95% CI: 1.15-1.84; IADL disability: OR=1.71, 95% CI: 1.47-1.99), Persistently Severe Loss (ADL disability: OR=2.33, 95% CI:1.93-2.82; IADL disability: OR=3.29, 95% CI: 2.82-3.84) and Edentulism (ADL disability: OR=3.25, 95% CI: 2.58-4.09; IADL disability: OR=3.60, 95% CI: 2.93-4.42) trajectories were significantly associated with an increased risk of functional disability with adjustment for potential confounders. CONCLUSION: Four distinct tooth loss trajectories were identified among older adults and those with severe tooth loss trajectories had an increased risk of functional disability than those with a mild loss trajectory.