Cognitive function, body mass index and mortality in a rural elderly Chinese cohort

Abstract

BackgroundPrevious studies have shown that poor cognition and low body mass index were associated with increased mortality. But few studies have investigated the association between cognition and mortality across the entire cognitive spectrum while adjusting for BMI. The objective of this study is to examine the associations between cognitive function, BMI and 7-year mortality in a rural elderly Chinese cohort.MethodsA prospective cohort of 2,000 Chinese age 65 and over from four rural counties in China were followed for 7-years. Cognitive function, BMI and other covariate information were obtained at baseline. Cox’s proportional hazard models were used to determine the effects of cognitive function and BMI on mortality risk.ResultsOf participants enrolled, 473 (23.7%) died during follow-up. Both lower cognitive function (HR = 1.48, p = 0.0049) and lower BMI (HR = 1.6, p < 0.0001) were independently associated with increased mortality risk compared to individuals with average cognitive function and normal weight. Higher cognitive function was associated with lower mortality risk (HR = 0.69, p = 0.0312). We found no significant difference in mortality risk between overweight/obese participants and those with normal weight.ConclusionsCognitive function and BMI were independent predictors of mortality risk. Intervention strategies for increasing cognitive function and maintaining adequate BMI may be important in reducing morality risk in the elderly population.

Association of cognitive impairment and elderly mortality: differences between two cohorts ascertained 6-years apart in China

“…The MMSE as a general measure of cognitive impairment has been an important predictor of all-cause mortality [28,29]. To date, although few studies have explored the relationship between cognitive impairment and all-cause mortality in China [30][31][32], the existing results support our conclusion that cognitive impairment is independently associated with an increased risk of death in the elderly [13,14]. Moreover, MMSE scores are known to be influenced by education [16].…”

“…Although a number of epidemiological studies have reported on a cognitive impairment-mortality relationship [3,7], most of them concerned the association of cognitive impairment and mortality risk of elders in high-income contries [8][9][10][11][12]. In upper-middle income countries such as China, several studies have indicated that baseline cognitive impairment increases the risk of all-cause mortality [13,14]. Earlier studies have found that education is strongly related with cognitive performance [15].…”

Cognitive Impairment and Risk of All‐Cause and Cardiovascular Disease Mortality Over 20‐Year Follow‐up: Results From the BLSA

“…To the best of our knowledge, only 2 studies have examined the relationship between baseline cognitive function and mortality in China 5, 6. Gao et al indicated that baseline cognitive function assessed by composite cognitive z‐score predicts future mortality incidence among a rural Chinese cohort aged ≥65 years 6.…”

“…To the best of our knowledge, only 2 studies have examined the relationship between baseline cognitive function and mortality in China 5, 6. Gao et al indicated that baseline cognitive function assessed by composite cognitive z‐score predicts future mortality incidence among a rural Chinese cohort aged ≥65 years 6. An and Liu showed that baseline cognitive impairment measured using the MMSE was inversely associated with longevity, although the population was confined to the oldest Chinese aged ≥80 years 5.…”

“…Most recent epidemiological studies have reported an association between cognitive impairment and increased risk of all‐cause mortality, with both mild and moderate‐to‐severe cognitive impairment being predictors of all‐cause mortality in older adults 3, 4. However, to our knowledge, very few studies have examined this relationship in China 5, 6. Analysis of the association between cognitive impairment and mortality in China is thus worthy of further research.…”