Selenium level and depressive symptoms in a rural elderly Chinese cohort.

BACKGROUND: Selenium is considered a protective agent against free radicals through the maintenance of better enzyme activity. The few studies examining the relationship between selenium and depression have yielded inconsistent results and none of these studies considered the role of cognitive function in this context. METHODS: A cross-sectional evaluation of 1737 rural Chinese age 65 and over from two provinces in China was conducted. Depressive symptoms were assessed using the Geriatric Depression Scale (GDS). Cognitive function was assessed using various cognitive instruments. Selenium measures were obtained from nail samples. Other information collected included demographic characteristics and medical history. Analysis of covariance models were used to identify factors associated with GDS score. RESULTS: Higher selenium levels were associated with lower GDS scores adjusting for demographic and medical conditions (p=0.0321). However, the association between selenium and depressive symptoms was no longer significant when cognitive function score was adjusted in the model (p=0.2143). CONCLUSIONS: Higher selenium level was associated with lower depressive symptoms without adjusting for cognition in this cohort. However, after cognition was adjusted in the model the association between selenium and depressive symptoms was no longer significant, suggesting that selenium's association with depressive symptoms may be primarily through its association with cognitive function.

[Study on selenium exposure level related to cognitive function in rural elderly people].

OBJECTIVE: To know the relationship between selenium exposure level and cognitive function and its influencing factors in rural elderly people. METHODS: A cross-sectional survey of 200 local rural elderly people were conducted by using dietary questionnaire and six cognitive questionnaires. The local environment samples were collected including food and nail and blood sample of study individuals. The trace amount of selenium were determined with 2, 3-diaminonaphthalenet fluorometric determination. Multiple stepwise regression was used to examine the association between selenium exposure level and the composite Z score adjusting for age, gender, education, and other factors that might influence the cognitive scores. RESULTS: There were significant positively relationships between three selenium exposure indexes. The results showed that food selenium intake level and blood selenium level could significantly affected the Z score after adjusting age, education and other factors by using multiple stepwise regression analysis (P < 0.001). CONCLUSION: Lower selenium exposure level maybe associated with lower cognitive function in rural elderly people.

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.

The association between selenium and lipid levels: a longitudinal study in rural elderly Chinese.

OBJECTIVE: A protective effect of selenium on lipid levels has been reported in populations with relatively low selenium status. However, recent studies found that high selenium exposure may lead to adverse cardiometabolic effects, particularly in selenium-replete populations. We examined the associations of selenium status with changes in lipid levels in a 7-year follow up of an elderly Chinese cohort including participants from selenium-deplete areas. METHODS: Study population consisted of 140 elderly Chinese aged 65 or older with nail selenium levels measured at baseline (2003-2005). Lipid concentrations were measured in fasting blood samples collected at baseline and the 7-year follow-up (2010-2012). Analysis of covariance (ANCOVA) models was used to determine the association between baseline selenium status and changes in lipid levels from baseline to follow-up adjusting for other covariates. RESULTS: Mean (±standard deviation) baseline selenium concentration was 0.41±0.2mg/kg. In prospective analysis, we found that individuals in the highest selenium quartile group showed 1.11 SD decrease on total-cholesterol (p<0.001), 0.41 SD increase on HDL-cholesterol (p<0.001) and 0.52 SD decrease on triglyceride after 7 years than those in the lowest selenium quartile group. The similar trends were seen with significant lipid changes in the 2nd and 3rd quartile groups. CONCLUSION: Selenium has modest beneficial effects on blood lipid levels in a population with relatively low selenium status. Our result suggests adequate dietary selenium intake as a potential prevention strategy for lowering lipid levels in selenium deplete populations.

[Progress on cerebral toxicity of arsenic].

It has been demonstrated in epidemiological studies in recent years that people exposed to chronic arsenic with high doses for a long time may lead to peripheral nervous symptoms. This paper reviewed the toxicity of arsenic on brain and the effects of superior nerve activities on central nervous system as well as the progress of its related mechanism.

[Effect of arsenic toxicity on morphology and viability of enzyme in primary culture of rat hippocampal neurons].

In order to study the toxic consequences of arsenic at different levels on hippocampal neurons of rat, different doses of sodium arsenite (0, 0.08, 0.40, 2.00 and 10.00 mg/L) were given to observe the changes of viability, morphological and biochemical parameters. The results showed that the arsenite content in primarily cultured rat hippocampal neurons decreased in growth of viable cells. The morphometric analysis showed that the isolated neonatal hippocampal neurons exposed to lower concentration of arsenic had cytoplasm vacuoles, frothing and nuclear condensation with the intact membrane, indicating the possible induction of apoptosis, whereas higher dose of arsenic leaded to the appearance of necrosis. The degeneration of cytoplasm with the appearance of large vacuoles and loss of cell-cell junction were also observed. Meanwhile the Nissles decreased in the cytoplasm confirmed by the Tolidine blue. Biochemically determined increase in the viability of L-LDH showed increased in extra-cellular release as well as decrease in AchE. Some results showed the dose-time dependent relationship. It is suggested that the neonatal hippocampal neurons of rat treated with different doses of arsenic suffered from morphological changes including degeneration, apoptosis and necrosis in various degrees.

[Study on distribution of endemic arsenism in China].

Drinking water and burning coal endemic arsenism as a severe disease is confirmed by National Ministry of Health in China in 1992. It is not uniform survey of the disease for the whole country from its report in 1980 in xijiang. Therefore National Ministry of Scientific and Technology in China supports to study on distribution of endemic arsenism in 21 provinces in China, so that it can know the basic distribution of endemic arsenism in China, and the data results will be a guide for the disease prevention and control. The project used environmental epidemiology study including retrospective epidemiology, present situation survey of the disease in severe areas and sampling investigation in unknown areas, collecting data of exposure population and arsenism cases. At the same time, the data of arsenic level in environment were collected, and environment samples were analyzed by standard chemical method. The both data were statistical analysis by access database and SAS procedure in computer. Through the study, it achieves the expected aim that grasps spreading distribution of drinking water arsenism and burning coal arsenism, including arsenic level in water, coal, food and air, as well as patient's condition of the disease at macroscopic. Drinking water endemic arsenism distributed in 8 provinces, 40 counties, affecting 2,343,238 peoples, among 522566 peoples expositing to the drinking water arsenic higher than 0.05 mg/L, and 7821 arsenism patients were diagnosed. Burning coal endemic arsenism spreads in 2 provinces, 8 counties, affecting 333905 peoples, 48438 peoples exposing to high arsenic of burning coal pollution, and 2402 peoples causing chronic arsenic poising by coal burning. Drinking water endemic arsenism: Nemeng, Shanxi is a severe drinking water endemic region also. Wusu city in Xinjiang is old arsenism area, which reformed drinking water to decrease arsenic, so chronic arsenic poisoning condition decreasing. Reforming drinking water measures to decreees arsenic were performed in some areas of Neimeng and Shanxi. On other hand, 1 county of Jilin and 1 county of Ningxia as drinking water arsenism areas were affirmed. 11 counties of Shanyi, 1 Banner of Nemeng, 1 city of Jilin, 1 county of Qinhai and 1 counties of Anhui province were discovered for new drinking water arsenism areas in this survey. Shunyi district of Beijing has high arsenic in drinking water. Otherwise, high arsenic content in drinking water in some areas decreased to lower than 0.05 mg/L, which including some villages of Liaoning province, Tongxing city of Zhejiang province, and Tianzhu village of Shunyi district in Beijing. Blackfoot disease related to high arsenic in drinking water in Taiwan province does not include in this study. Burning coal endemic arsenism: Guizhou province has a typical burning coal arsenism areas in China and world. Although to reform stove and decreasing arsenic pollution, but the chronic arsenic poisoning from domestic coal combustion exists, because it located high seal level and poor areas. Some new burning coal arsenism areas in Shanxi province were found, which produced air pollution and food pollution of arsenic from domestic coal combustion for cooking and heating. The paper summarizes the arsenic distribution levels in drinking water and in environment of burning coal. At the same time, preventive and control measures of endemic arsenism were provided.

[Relations between trace elements in drinking water and elderly residents' cognitive function].

The relationship between trace element levels in drinking water and cognitive function was studied for elderly residents in rural areas in China. Cognitive function was measured by a Chinese translation of the Community Screening Interview for Dementia (CSI "D"). The trace elements fluoride, calcium, selenium, aluminum, iron, zinc, cadmium, lead and arsenic contents of drinking water were determined using Chinese. National Standard Methods. A mixed effects model was used to evaluate the effect of each of the elements on cognitive function while adjusting for age, sex, and education level. Several of the elements examined had a significant effect on cognitive function when they were examined in a univariate context. However, after adjusting for other elements many of these results were not significant. There was a significant quadratic effect for calcium and a significant zinc-cadmium interaction. Cognitive function increased with calcium level to a certain point, and then decreased as calcium continued to increase. Zinc showed a positive relationship with cognitive function at low cadmium levels, but a negative relationship at high cadmium levels.

Late life leisure activities and risk of cognitive decline.

BACKGROUND: Studies concerning the effect of different types of leisure activities on various cognitive domains are limited. This study tests the hypothesis that mental, physical, and social activities have a domain-specific protection against cognitive decline. METHODS: A cohort of a geographically defined population in China was examined in 2003-2005 and followed for an average of 2.4 years. Leisure activities were assessed in 1,463 adults aged 65 years and older without cognitive or physical impairment at baseline, and their cognitive performances were tested at baseline and follow-up examinations. RESULTS: High level of mental activity was related to less decline in global cognition (ß = -.23, p < .01), language (ß = -.11, p < .05), and executive function (ß = -.13, p < .05) in ANCOVA models adjusting for age, gender, education, history of stroke, body mass index, Apolipoprotein E genotype, and baseline cognition. High level of physical activity was related to less decline in episodic memory (ß = -.08, p < .05) and language (ß = -.15, p < .01). High level of social activity was associated with less decline in global cognition (ß = -.11, p < .05). Further, a dose-response pattern was observed: although participants who did not engage in any of the three activities experienced a significant global cognitive decline, those who engaged in any one of the activities maintained their cognition, and those who engaged in two or three activities improved their cognition. The same pattern was observed in men and in women. CONCLUSIONS: Leisure activities in old age may protect against cognitive decline for both women and men, and different types of activities seem to benefit different cognitive domains.

Normative data for neuropsychological tests in a rural elderly Chinese cohort.

Normative information is important for appropriate interpretation of cognitive test scores as a critical component of dementia diagnosis in the elderly population. A cross-sectional evaluation of 1826 participants aged 65 years and older from four rural counties in China was conducted using six cognitive instruments including tests of global cognitive function (the Community Screening Instrument for Dementia), memory (Word List Learning and Recall tasks from the Consortium to Establish a Registry for Alzheimer's Disease, IU Story), language (Animal Fluency Test), and executive function (IU Token). Multiple regression models adjusting for demographic variables were used to provide standardized residuals z-scores and corresponding percentile ranking for each cognitive test. In all cognitive tests older age was associated with worse test performance while exposure to education was related to better cognitive test performance. We also detected a significant gender difference with men scoring better than women and a significant gender by education interaction on two tests. The interaction indicates that gender difference in test scores was much smaller in participants with more education than those who had less or no education. These demographically adjusted, regression-based norms can be a useful tool to clinicians involved with differential diagnosis of cognitive and memory disorders in older adults in rural China.

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.