Mild cognitive impairment risk related to multiple functional impairments in older adults in Taiwan

BACKGROUND: Mild cognitive impairment (MCI) is a critical transition stage toward dementia, making the identification of modifiable risk factors essential for early intervention. While individual conditions such as sensory loss, tooth loss, and psychological distress are independently linked to cognitive decline, their cumulative and combined longitudinal effects remain under-researched. Therefore, we aimed to evaluate the association between the number and specific combinations of multiple functional impairments, including vision, hearing, tooth loss, and psychological distress, and the risk of incident MCI among community-dwelling older adults in Taiwan. METHODS: This cohort study analyzed data from 57,494 adults aged ≥65 years who participated in the Taipei City Government's annual physical examination program from 2005 to 2011. The study population comprised community-dwelling older adults with at least two examination records. Functional impairments were categorized as vision impairment, hearing impairment, tooth loss, and psychological distress, assessed via objective measurements and self-administered questionnaires. Impairments ranged from none to multiple. The primary outcome was incident MCI, assessed using the Short Portable Mental Status Questionnaire. Associations between the number and type of impairments and MCI were analyzed using multivariable-adjusted generalized estimating equation models. RESULTS: Participants with multiple functional impairments had a significantly higher risk of developing MCI than those without impairments. The adjusted odds ratio (aOR) was 1.57 (95% confidence interval (CI), 1.40-1.76) for a single impairment, 2.41 (95% CI, 2.11-2.76) for dual impairments, and 2.94 (95% CI, 2.38-3.64) for multiple impairments. Combinations involving visual impairment, tooth loss, and psychological distress showed an aOR of 3.40 (95% CI, 2.61-4.44). The highest risk was observed in participants with all four functional impairments (aOR, 5.06; 95% CI, 2.76-9.27). CONCLUSION: These findings suggest that older adults with multiple functional impairments are at a higher risk of developing MCI. Comprehensive assessment and multifaceted intervention strategies targeting multiple impairments may be crucial for reducing the risk of cognitive decline in this population.