Modifiable Factors Associated with Mortality among the Oldest Old with Cognitive Impairment: A Longitudinal Study in China

Abstract

AbstractBackgroundThe oldest old (aged above 80 years) have the highest death rate, and CI (Cognitive Impairment) significantly increases risk of mortality. Studies investigating mortality associated with dementia mostly identified non‐modifiable factors, providing limited practical implications. This study aims to investigating factors associated with mortality among the oldest old with dementia, with particular focus on modifiable factors.MethodOur study included 6,997 older adults aged 80 years above who were diagnosed with CI. Data were from the Chinese Longitudinal Healthy Longevity Study (CLHLS). CI was measured by the Mini‐mental State Examination (MMSE). Cox proportional hazard regression combined with Least Absolute Shrinkage and Selection Operator (LASSO) was applied to select factors and evaluate their association with mortality of the oldest adults with CI.ResultOf the 6,997 participants, 6,451 died with median survival time of 2.2 years. 21 out of the 56 variables were selected from the LASSO‐penalized Cox regression model. Consistent with previous studies, the hazard of mortality increases by 19% with every incremental 10 years of age (95% CI: 12‐27%). The hazard of morality among women was 23% lower than that of men (95% CI: 18%‐29%). History of diabetes also increases the hazard of mortality. In terms of modifiable factors, daily outdoor activities, daily watching TV or listening to the radio, being married, good chewing ability are associated with lower mortality, while smoking and high systolic blood pressure increases the risk of mortality in a dose‐response manner.ConclusionSeveral modifiable factors are associated with mortality among the oldest adults with CI. Analysis suggests that healthy diet, cognitive stimulating leisure activities, marriage, and good chewing ability may contribute to lowering the risk of mortality among this population.