Association between body mass index, its change and cognitive impairment among Chinese older adults: a community-based, 9-year prospective cohort study

Abstract

Objective To examine the association of baseline body mass index (BMI) and BMI change with cognitive impairment among older adults in China.Methods The study included data from the Chinese Longitudinal Healthy Longevity Study, a national community-based prospective cohort study from 2002-2018. Baseline BMI and BMI change measurements were available for 12,027 adults aged older than 65 years. Cognitive impairment was de ned as Chinese version of the Mini Mental State Examination score less than 18. Multivariable Cox proportional hazard model was used.Results Among 12027 participants (mean age was 81.23 years old and 47.48% were male), the proportion of underweight, normal, overweight and obese at baseline was 33.87%, 51.39%, 11.39% and 3.34%, respectively. During an average of 5.9 years' follow-up, 3086 participants (4.35 per 100 person-years) with incident cognitive impairment were identi ed. Compared with normal weight group, adjusted hazard ratio (AHR) for cognitive impairment was 0.86 (95% CI 0.75-0.99) among overweight group, whereas corresponding AHR was 1.02 (95% CI 0.94-1.10) in underweight and 1.01 (95% CI 0.80-1.28) in obese. Large weight loss (<-10%) was signi cantly associated with an increased risk of cognitive impairment (AHR, 1.42, 95% CI 1.29-1.56), compared to stable weight status group (-5%~5%). In the restricted cubic spline models, BMI change showed a L-shaped association with cognitive impairment.Conclusions BMI-de ned overweight is associated with a reduced risk of cognitive impairment among Chinese older adults, while large weight loss is associated with increased risk. More attention should be paid to older adults with signi cant weight loss.We are grateful to all cooperating organizations and their staff in CLHLS whose hard work made this study possible. We thank the interviewees and their families for their voluntary participation in the CLHLS study.

Body Mass Index, Waist Circumference, and Cognitive Decline Among Chinese Older Adults: A Nationwide Retrospective Cohort Study

“…We also found that Chinese older adults with both large weight gain and large WC loss were associated with faster cognitive decline. A nationally representative American cohort indicated that a BMI decrease and a WC increase >10% over a 3-year follow-up were related to an increased risk of cognitive decline among older adults (Rodriguez-Fernandez et al, 2017 ), and a recent large cohort study in China reported that large weight loss was associated with an increased risk of cognitive impairment (Wu et al, 2021 ). Losing weight was found to be associated with worse cognitive performance or greater risk of cognitive impairments in later life (Atti et al, 2008 ; Hughes et al, 2009 ; Tolppanen et al, 2014 ; West et al, 2017 ).…”

“…We used the baseline information and up to three follow-up assessments to calculate person-specific BMI or WC range at each follow-up for each participant (Capuano et al, 2018 ; Aiken-Morgan et al, 2020 ). In addition, BMI and WC change were classified into 5 groups, namely, large loss (< -10%), small loss (−10 to −5%), stable (−5 to <5%), small gain (5 to <10%), and large gain (more than 10%; Newman et al, 2001 ; Wu et al, 2021 ).…”

“…Body mass index (BMI) was calculated as weight in kilograms divided by the square of height in meters. According to the criteria of weight for Chinese adults, baseline BMI (kg/m 2 ) was categorized as follows: underweight (BMI < 18.5), normal (18.5 ≤ BMI < 23.9), overweight (24 ≤ BMI < 27.9), and obese (BMI ≥ 28) (Wu et al, 2021). Baseline WC (cm), as indicators of central adiposity, was classified into three categories: no central obesity (WC < 85 for men and WC < 80 for women), central pre-obesity (85 ≤ WC < 90 for men and 80 ≤ WC < 85 for women), and central obesity (90 ≤ WC for men and 85 ≤ WC for women; Jia et al, 2010).…”

Association of Body Mass Index and Plant-Based Diet with Cognitive Impairment among Older Chinese Adults: A Prospective, Nationwide Cohort Study

“…The MMSE contains a total of 30 items that assess orientation, registration, attention and calculation, recall, and language, with a score range from zero to 30 [ 36 , 37 ]. Use of the MMSE in the CLHLS is well-documented as both reliable and valid [ 22 , 35 , 38 , 39 , 40 , 41 ]. Since MMSE scores might be influenced by education level [ 40 ], participants were defined as cognitively impaired following education-based MMSE cutoff points.…”

“…Our previous results suggested that a larger BMI and a BMI-defined overweight status were related to slower cognitive decline [ 13 ]. A cohort study reported that BMI-defined overweight status was associated with a lower risk of cognitive impairment [ 22 ], and another recent cohort study suggested that a BMI-defined underweight status was related to a higher risk of cognitive impairment [ 23 ].…”