Abstract P037: Body Mass Index in Relation to Memory Performance in Chinese Older Adults: The China Health and Nutrition Survey
Introduction. China is witnessing a dramatic increase in its aging population, with growing numbers at risk of developing Alzheimer’s disease (AD). Memory loss represents the earliest manifestation of neuropsychological changes typically observed in early onset AD, however little is known regarding the association between body mass index (BMI) and memory performance in Chinese older adults.
Hypothesis. We assessed the hypothesis that being underweight or obese in Chinese older adults is associated with: 1) poorer verbal episodic memory functioning, and 2) greater loss in verbal episodic memory functioning over time.
Methods. This study comprised a household-based sample of older adults aged 55 and older who undertook cognitive function tests in 2000 and 2006 within the China Health and Nutrition Survey (CHNS) (n=1083). Our outcomes of interest were immediate and delayed memory scores of a ten-word verbal-learning task. Multivariable linear regression models were used to study the relation between BMI measured in 2000 and concurrent and 6-year changes in immediate and delayed memory scores, adjusting for age, gender, education, urbanization index, alcohol consumption and cigarette smoking, as well as the average of 2000 and 2006 scores to address regression to the mean when studying memory change. BMI was treated as categorically, according to established Chinese guidelines [underweight (<18.5 kg/m2), normal weight (18.5-23.9 kg/m2), overweight (24-27.9 kg/m2) and obese (≥28 kg/m2)]. Extensive sensitivity analyses were performed for BMI and memory functioning change including exploring the impact of: 1) excluding adjustment for average scores or adjusting baseline scores; 2) stratification by age (<65 vs. ≥65y); and 3) restricting the analysis to those who had scores at baseline ≥3.
Results. The prevalence of underweight and obesity among this Chinese older population was 8% and 28% respectively, with a mean age of 64y. Compared with those of normal weight, underweight older adults had significantly lower delayed word-list recall scores measured in 2000 [-0.80 (95%CI = -1.32, -0.27)], which was equivalent to the mean disparity in scores observed for an 11-year difference in age. We did not observe a significant relation between BMI and immediate memory scores or 6-year change in immediate and delayed memory functioning; results remained consistent in sensitivity analyses.
Conclusions. Being underweight in older adulthood is associated with poorer general memory, but was not predictive of 6-year declines of verbal episodic memory functioning in this older Chinese population. This is the first study conducted in a representative population of older Chinese to study the relationship of BMI with cognitive function or change. Future studies are needed to replicate these findings, and to study associations between BMI changes over time and cognitive function decline.
- © 2013 by American Heart Association, Inc.