Regional areas and widths of the midsagittal corpus callosum among HIV-infected patients on stable antiretroviral therapies.

Recent reports suggest that a growing number of human immunodeficiency virus (HIV)-infected persons show signs of persistent cognitive impairment even in the context of combination antiretroviral therapies (cART). The basis for this finding remains poorly understood as there are only a limited number of studies examining the relationship between CNS injury, measures of disease severity, and cognitive function in the setting of stable disease. This study examined the effects of HIV infection on cerebral white matter using quantitative morphometry of the midsagittal corpus callosum (CC) in 216 chronically infected participants from the multisite HIV Neuroimaging Consortium study currently receiving cART and 139 controls. All participants underwent MRI assessment, and HIV-infected subjects also underwent measures of cognitive function and disease severity. The midsagittal slice of the CC was quantified using two semi-automated procedures. Group comparisons were accomplished using ANOVA, and the relationship between CC morphometry and clinical covariates (current CD4, nadir CD4, plasma and CSF HIV RNA, duration of HIV infection, age, and ADC stage) was assessed using linear regression models. HIV-infected patients showed significant reductions in both the area and linear widths for several regions of the CC. Significant relationships were found with ADC stage and nadir CD4 cell count, but no other clinical variables. Despite effective treatment, significant and possibly irreversible structural loss of the white matter persists in the setting of chronic HIV disease. A history of advanced immune suppression is a strong predictor of this complication and suggests that antiretroviral intervention at earlier stages of infection may be warranted.

Correlates of depressive symptoms in rural elderly Chinese.

OBJECTIVE: Late life depression has been studied in many populations around the world. However, findings on risk factors for late life depression have remained inconsistent. METHODS: A cross-sectional survey of 1737 rural Chinese age 65 and over from two provinces in China was conducted assessing cognitive functions using various cognitive instruments and collecting information on demographic characteristics and medical history. Depressive symptoms were assessed using the Geriatric Depression Scale (GDS). Analysis of covariance and logistic regression models were used to identify factors associated with the continuous GDS score, mild or severe depression. RESULTS: In this cohort, 26.5% (95% CI: 24.4-28.6%) met the criteria for mild depression and 4.3% (95% CI: 3.4-5.4%) for severely depression. Living alone, history of heart attack, head injury, and fracture were associated with higher depressive symptoms. Alcohol consumption and higher cognitive function were associated with lower depressive symptoms. Living alone, not attended school, history of head injury, fracture, and low cognitive function were associated with increased probability of mild depression. Living alone, history of stroke or heart attack, and low cognitive function were associated with severe depression. CONCLUSIONS: Depression, particularly mild depression, is common in rural elderly Chinese. Among a number of factors identified in this cohort as being significantly associated with depressive symptoms, living alone and lower cognitive function were the most consistent factors associated with depressive symptoms, mild and severe depression. History of stroke, heart attack, and fracture were also risk factors for depressive symptoms.

Selenium level is associated with apoE epsilon4 in rural elderly Chinese.

OBJECTIVE: Se is an essential trace element in human nutrition associated with antioxidant activity. Previous studies on predictors of toenail Se or serum Se have mostly concentrated on demographic factors such as age and gender. The present paper examines the association between apoE genotype and Se levels in nail samples in a rural elderly Chinese cohort. DESIGN: Two thousand Chinese aged 65 years and over from four counties in China were enrolled in a cohort to study the association of Se with cognitive decline. Nail samples were collected from each participant and analysed for Se levels. Dietary Se intake was estimated from an FFQ using Se contents measured in food items collected from each village. Blood samples on filter cards were collected and analysed for apoE genotype. Mixed-effect models were constructed with nail Se level as the dependent variable and each village as the random effect, which controlled for the potential confounding effect from correlation in Se measures obtained from participants residing in the same village. RESULTS: In this elderly Chinese cohort, carriers of the apoE epsilon4 allele had significantly lower Se levels measured in nail samples than non-carriers after adjusting for other significant covariates and controlling for estimated dietary Se intake. There was no significant difference between the two genotypes on estimated Se dietary intake (P = 0.6451). CONCLUSIONS: Future studies are needed to examine the mechanism underlying the association between the apoE epsilon4 allele and Se levels, including the role of oxidative stress and that of reduced lipid metabolism in the apoE epsilon4 carriers.

Trace element levels and cognitive function in rural elderly Chinese.

BACKGROUND: Trace elements are involved in metabolic processes and oxidation-reduction reactions in the central nervous system and could have a possible effect on cognitive function. The relationship between trace elements measured in individual biological samples and cognitive function in an elderly population had not been investigated extensively. METHODS: The participant population is part of a large cohort study of 2000 rural elderly Chinese persons. Six cognitive assessment tests were used to evaluate cognitive function in this population, and a composite score was created to represent global cognitive function. Trace element levels of aluminum, calcium, cadmium, copper, iron, lead, and zinc were analyzed in plasma samples of 188 individuals who were randomly selected and consented to donating fasting blood. Analysis of covariance models were used to assess the association between each trace element and the composite cognitive score adjusting for demographics, medical history of chronic diseases, and the apolipoprotein E (APOE) genotype. RESULTS: Three trace elements-calcium, cadmium, and copper-were found to be significantly related to the composite cognitive score. Increasing plasma calcium level was associated with higher cognitive score (p <.0001). Increasing cadmium and copper, in contrast, were significantly associated with lower composite score (p =.0044 and p =.0121, respectively). Other trace elements did not show significant association with the composite cognitive score. CONCLUSIONS: Our results suggest that calcium, cadmium, and copper may be associated with cognitive function in the elderly population.

Hypertension and cognitive decline in rural elderly Chinese.

OBJECTIVES: To examine the association between hypertension and cognitive decline in older adults. DESIGN: Prospective observational study. SETTING: Four rural counties in China. PARTICIPANTS: Two thousand rural Chinese aged 65 and older (median age 70, range 65-92) participated in a baseline evaluation. A follow-up evaluation of 1,737 subjects was conducted 2.5 years after baseline. MEASUREMENTS: Cognitive function was assessed using the Community Screening Instrument for Dementia (CSID), Consortium to Establish a Registry for Alzheimer's Disease (CERAD) Word List Learning and Recall Tests, Indiana University (IU) Story Recall Test, Animal Fluency Test, and IU Token Test. Hypertension was defined as the mean of two readings of systolic blood pressure (BP) of 140 mmHg or greater, diastolic BP of 90 mmHg or greater, or according to self-report. Cognitive decline was derived as the difference between baseline and follow-up scores. Analysis of covariance models were used to estimate the association between hypertension, BP, and cognitive decline, adjusting for other covariates. RESULTS: Greater decline was found on the CERAD 10-Word List Learning (P<.001) and Recall (P=.01) scores for subjects with hypertension than for those without. In particular, significantly greater decline was seen in the group with hypertension that was not taking medication than in the group without hypertension. No significant difference on cognitive decline was found between subjects with hypertension who were taking medication and those without hypertension. CONCLUSION: Untreated hypertension was associated with greater cognitive decline in this Chinese cohort. Better hypertension detection and treatment in elderly people, especially in developing countries, may offer protection against cognitive decline.

Selenium level and cognitive function in rural elderly Chinese.

Selenium is a trace element associated with antioxidant activity and is considered to be a protective agent against free radicals through enhanced enzyme activity. Studies on selenium and cognitive function or Alzheimer's disease have yielded inconsistent results. A cross-sectional survey of 2,000 rural Chinese aged 65 years or older from two provinces in the People's Republic of China was conducted from December 2003 to May 2005 by use of the Community Screening Instrument for Dementia, the Consortium to Establish a Registry for Alzheimer's Disease (CERAD) Word List Learning Test, the Indiana University Story Recall Test, the Animal Fluency Test, and the Indiana University Token Test. Over 70% of the study participants have lived in the same village since birth. Nail samples were collected and analyzed for selenium contents. Analysis-of-covariance models were used to estimate the association between quintile selenium levels measured in nail samples and cognitive test scores, with adjustment for other covariates. Lower selenium levels measured in nail samples were significantly associated with lower cognitive scores (p < 0.0087 for all tests) except the Animal Fluency Test (p = 0.4378). A dose-response effect of selenium quintiles was also seen for those significant associations. Results in this geographically stable cohort support the hypothesis that a lifelong low selenium level is associated with lower cognitive function.