| Background:Evidence has emerged that anemia is associated with cognitive impairment and dementia in older people.Cognitive impairment(CI)refers to the impairment of one or more cognitive domains in memory,language,execution,comprehension,calculation and visual space.According to the degree of the disease,it can be divided into mild cognitive impairment(MCI)and dementia.With the increasingly serious aging population in China,the prevalence of cognitive impairment increases year by year,which brings huge psychological and economic burden to the society and families.Therefore,the exploration of modifiable risk factors is crucial for the early diagnosis and prevention of cognitive impairment.Anemia is a common disease of the elderly and its etiology is complex,which often co-exist with a variety of diseases.Studies have shown that anemia and hemoglobin levels are associated with cognitive function in older adults.However,the relationship is poorly understood in low-and middle-income countries,especially among older people living in rural areas.Therefore,the purpose of this study was to explore the relationship between anemia and hemoglobin and mild cognitive impairment and dementia.Objective:1.To analyze cognitive impairment epidemiological situation among the rural-dwelling adults who were aged 65 years or older in Shandong province;2.To analyze the associations of anemia and hemoglobin with cognitive impairment among the rural-dwelling adults who were aged 65 years or older in Shandong province;3.To analyze the associations of anemia and hemoglobin with global cognitive performance score among the rural-dwelling adults who were aged 65 years or older in Shandong province;Methods:This population-based cross-sectional study included 4,838 participants(age>65 years)who participated in Shandong Yanggu Cohort Study of Aging and Dementia.Data on demographics,lifestyle,clinical conditions,and cognitive function were collected through face-to-face interviews,physical examinations,and laboratory tests.Anemia was defined as hemoglobin<13 g/dl in men and<12 g/dl in women.We define cognitive function as cognitively normal,mild cognitive impairment,and dementia,respectively.Overall cognitive function,memory,attention,language and executive function were evaluated by professional neuropsychological test battery.Participants were grouped according to their cognitive functions and the data were analyzed by chi-square test,t-test,multinomial logistic and general linear regression models.Results:1.The overall prevalence of anemia among the 4838 participants was 20.1%,15.1%for men and 23.9%for women.The prevalence in people with normal cognition,MCI,and dementia were 19.2%,22.8%,and 26.3%,respectively.Compared with cognitively normal,participants with mild cognitive impairment and dementia were more likely to have anemia(P1=0.027;P2=0.003)2.After adjusting for covariates such as age,sex,education,drinking,smoking,Body Mass Index(BMI),stroke,hypertension,diabetes,dyslipidemia,renal dysfunction and depression,the subjects with anemia had a higher risk of MCI compared to those without anemia(multiple-adjusted OR=1.25;95%CI 1.02 to 1.54;P=0.034).In the same model,the subjects with anemia had a higher risk of dementia than those without anemia,but there was no statistically significant difference(OR=1.26;95%CI 0.86 to 1.86;P=0.245).3.After the linear regression model was established and above covariates were adjusted,anemia was associated with lower global cognitive performance(?=-0.51;95%CI=-0.84 to-0.18;P=0.003).Similarly,higher hemoglobin levels were significantly linearly correlated with higher overall cognitive scores(P for trend=0.002).Conclusions:The present study found that anemia was associated with increased prevalence of MCI and decreased overall cognitive score in elderly population in rural China,but no significant association with dementia.In addition,a higher hemoglobin level was correlated with better cognitive performance. |
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