Synergistic Impact of Body Mass Index and Cognitive Function on All-Cause Mortality in Older Adults: A Nationwide Longitudinal Study

Abstract

BackgroundBody mass index (BMI) and cognitive function are independent predictors of mortality risk. However, little is known about the combined impact of BMI and cognitive function on the risk of all-cause mortality in older adults. In this study, we aimed to examine the associations between BMI, cognitive function, and all-cause mortality, including between-factor interactions, in the general population of older adults in China.MethodsWe used the data between 2011 and 2018 from the Chinese Longitudinal Healthy Longevity Survey that included adults aged ≥65 years residing in the 23 provinces of China. The association between BMI and cognitive function on all-cause mortality was examined with the Cox proportional hazards regression model.ResultsThe study included 8,293 Chinese older adults. Low BMI (underweight) and cognitive impairment were associated with the highest risk of death after adjustments [hazard ratio (HR) = 2.18; 95% confidence interval (CI), 1.96–2.41]; this combined effect was more prominent among adults aged <100 years and women. In addition, there was an interaction effect of BMI and cognitive impairment on all-cause mortality (P <0.001). Concurrently, among older adults with normal cognition, the risk of mortality related to underweight was higher than among their cognitively impaired counterparts [55% (normal cognition) vs. 38% (cognitive impairment)].ConclusionsLow BMI (underweight) and cognitive impairment were independently and jointly associated with increased risk of all-cause mortality among Chinese older adults, and females showed a stronger effect in this association. The association between BMI and mortality was more pronounced in the participants with normal cognition than in their cognitively impaired counterparts.

Synergistic impact of diabetes and cognitive impairment on all-cause and cause-specific mortality in Chinese older adults: A prospective population-based cohort study

“…In our subgroup analysis of diabetes, we found that the risk of all-cause and CVD death in the DM group was much higher than that in the non-DM group after adjusting for potential confounders. We also found a linear (dose–response) relationship between MMSE and mortality, which was consistent with previous studies ( 25 ). Interestingly, we found that the shape of the curve depicting the association between MMSE and mortality differed according to DM.…”

“…Our results provide evidence that supports screening for CI and DM in older adults. Furthermore, several previous studies have explored the interaction effects of CI and age, gender, anemia, and BMI on mortality risk in different populations ( 25 , 34 ). The present study expanded on the evidence, finding a significant interaction of DM and CI on all-cause and CVD mortality.…”

“…The MMSE score ranges from 0 to 30; the lower the score, the more severe cognitive problems. This study used the Chinese version of MMSE, which has been validated in the Chinese population for screening test ( 24 , 25 ) Consistent with the method described in the previous study ( 21 ), CI was defined using education-adjusted MMSE cutoff points (MSE <17, uneducated participants; MMSE <20, participants with primary education level; MMSE <24, participants with over 6 education years).…”

“…Restricted cubic splines with three knots at 17, 21, and 24 points (MMSE) were used to analyze the association of MMSE with mortality in total study participants and participants with or without DM based on the fully adjusted Cox proportional hazards model. The likelihood ratio test was used to test for potential non-linearity ( 25 , 27 ).…”

Interaction of High-Sugar Diet and History of Stroke with Risk of Cognitive Decline in Older Adults

“…Brain aging may increase the risk of behavioral dysfunction and cognitive decline, which is a common geriatric syndrome in older adults, with an increased prevalence in Chinese adults aged ≥60 years [ 2 ]. Cognitive decline has become a public health concern as it brings adverse economic and socio-psychological outcomes [ 3 , 4 ]. Cognitive decline decreases the quality of life and the ability to perform instrumental activities of daily living, which is thought to be the precursor symptom of dementia [ 5 , 6 ].…”