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To investigate the relationship between selenium (Se) based multi-element combined exposure and cognitive function in rural elderly individuals, a cross-sectional study was conducted. The study involved 416 older adults aged 60 and above, residing in four different areas of Enshi county, China, with varying soil Se levels. Inductively coupled plasma mass spectrometry (ICP-MS) was employed to measure the concentrations of Se, copper (Cu), iron (Fe), zinc (Zn), calcium (Ca), magnesium (Mg), cadmium (Cd), arsenic (As), and lead (Pb) in whole blood. Nine standard cognitive tests were applied to assess cognitive function. Analysis of the least absolute shrinkage and selection operator regression (LASSO), covariance (ANCOVA), and generalized linear model (GLM) were utilized to investigate the relationship between element exposure and cognitive function. The results of LASSO revealed that Se, Cu, Fe, Zn, Ca, and Pb were independently identified to be associated with cognition. Both ANCOVA and GLM demonstrated that Se and Ca were correlated with cognitive function. The multi-element model showed higher composite Z scores of 0.32 (95% CI: 0.09 to 0.55) for log-transformed Se (P = 0.007), 0.75 (95% CI: 0.01 to 1.49) for log-transformed Cu (P = 0.048), and a lower score of - 0.67 (95% CI: - 1.26 to - 0.08) for log-transformed Ca (P = 0.025). Furthermore, there was evidence that Se could counteract the negative impact of Ca on cognitive function (P for interaction = 0.031). Our findings suggested that higher levels of Se and Cu were associated with better cognitive function in the elderly and Se can counteract the cognitive damage caused by Ca.

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BACKGROUND: Studies have established the association between blood ß-amyloid (Aß) levels and Alzheimer's disease, but population-based studies concerning the association between selenium (Se) and Aß levels in blood samples are very limited. Therefore, we explored the association in an elderly population with Se status and serum Aß measures. METHODS: A cross-sectional study on 469 elderly individuals from four rural counties with diverse soil Se levels was carried out. Fasting blood Se, serum selenoprotein P (SELENOP), and glutathione peroxidase (GPX), serum Aß42, and Aß40 were measured. Quantile regression models were used to determine the associations of blood Se, serum GPX, and SELENOP with Aß levels. RESULTS: Significant negative associations were observed between blood Se and serum Aß42 and Aß40 levels at all percentiles (P < 0.05). The associations were generally stronger at higher Aß42 and Aß40 percentiles than lower Aß42 and Aß40 percentiles. Blood Se was positively associated with serum Aß42/Aß40 ratio at 25th, 50th, and 75th percentiles. Significant positive associations were observed between serum GPX and Aß42 and Aß40 levels at all percentiles (P < 0.05). The positive associations were generally stronger at higher Aß42 and Aß40 percentiles than at lower percentiles. Serum GPX was negatively associated with Aß42/Aß40 ratio at 25th, 50th, 75th, and 95th percentiles. No associations with serum SELENOP and Aß levels were observed. CONCLUSIONS: Our results suggest that higher Se levels are associated with lower serum Aß42 and Aß40 levels and with higher Aß42/Aß40 ratio, and the results are specific for different selenoproteins.

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BACKGROUND AND AIMS: Earlier studies have reported inconsistent association between selenium (Se) and homocysteine (Hcy) levels, while no evidence could be found from Chinese population. To fill this gap, we investigated the association between blood Se and hyperhomocysteinemia (HHcy) of rural elderly population in China. METHODS: A cross-sectional study on 1823 participants aged 65 and older from four Chinese rural counties was carried out in this study. Whole blood Se and serum Hcy concentrations were measured in fasting blood samples. Analysis of covariance and restricted cubic spline models were used to examine the association between Se and Hcy levels. Logistic regression models were used to evaluate the risk of prevalent HHcy among four Se quartile groups after adjusting for covariates. RESULTS: For this sample, the mean blood Se concentration was 156.34 (74.65) µg/L and the mean serum Hcy concentration was 17.25 (8.42) µmol/L. A significant non-linear relationship was found between blood Se and serum Hcy, the association was inverse when blood Se was less than 97.404 µg/L and greater than 156.919 µg/L. Participants in the top three blood Se quartile groups had significantly lower risk of prevalent HHcy compared with the lowest quartile group. When defined as Hcy> 10 µmol/L, the odds ratios and 95% confidence interval of HHcy were 0.600 (0.390, 0.924), 0.616 (0.398, 0.951) and 0.479 (0.314, 0.732) for Q2, Q3, and Q4 Se quartile groups compared with the Q1 group, respectively. When defined as Hcy≥ 15 µmol/L, the odds ratios and 95% confidence interval of HHcy were 0.833 (0.633, 1.098) and 0.827 (0.626, 1.092), 0.647 (0.489, 0.857) for Q2, Q3, and Q4 Se quartile groups compared with Q1 group. CONCLUSIONS: Our findings suggest that higher blood Se level could be a protective factor for HHcy in the elderly.

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Although the association between selenium (Se) and diabetes has been well-discussed in recent years, few studies have focused on the effects of long-term natural Se exposure and rarely concerned the effects of different Se biomarkers. To address this question, we carried out a 7-year longitudinal study on older adults aged over 65 and another cross-sectional study on middle-aged and older adults aged 40 and above from Chinese soil Se-deplete and Se-optimum areas. Cox proportional hazard models were used to evaluate the associations between nail Se levels and incidence risk of diabetes. Unconditional logistic regression models and analysis of variance models were used to examine the associations between serum Se levels and the prevalence risk of diabetes. The nail and serum Se levels were 0.47 ± 0.20 µg/g and 111.09 ± 55.01 µg/L for the two study populations, respectively. For both of the independent studies, higher Se levels were observed to be associated with a higher risk of diabetes and prediabetes. Compared with the Second nail Se quartile (Q2), the adjusted hazard ratios (HRs) and 95 % confidence intervals (95 % CIs) of diabetes for Q1, Q3 and Q4 were 1.24(0.70, 2.21), 1.53(0.98, 2.39) and 1.31(0.76, 2.26), respectively, and the adjusted HRs (95 % CIs) of prediabetes were 1.47(0.77, 2.81), 1.38(0.83, 2.30), and 1.97(1.13, 3.44), respectively. Compared with the first serum Se quintile (Q1), the adjusted odds ratios (ORs) and 95 % CIs of diabetes for higher quintiles were 1.12(0.75, 1.66), 1.05(0.71, 1.57), 1.09(0.73, 1.62) and 1.51(1.02, 2.19), and the adjusted ORs (95 % CIs) of prediabetes were 1.27(0.77, 2.09), 1.70(1.05, 2.74), 1.94(1.21, 3.11) and 1.67(1.03, 2.71). Our findings consistently suggest that higher Se status is associated with a higher risk of diabetes in adults.

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Cadmium (Cd) exposure has been reported to have neurotoxic effects in animal studies and associated with increased Alzheimer's Disease mortality and lower cognitive function in cross-sectional and case-control studies. However, no results from longitudinal studies on Cd and cognitive decline are available. In this prospective cohort study, we recruited 1867 participants aged 65 years or older from rural areas in China, blood Cd and cognitive function were measured at baseline (2010-2012), and 1554 participants completed cognitive function tests during a 3-year follow-up (2013-2015). Cognitive function was evaluated using nine standardized cognitive tests: The Community Screening Instrument for Dementia, the CERAD Word List Learning, Word list recall, IU Story Recall, Animal Fluency Test, Boston Naming Test, Stick Design, Delayed Stick Design and the IU Token Test. Analysis of covariance models and logistic regression models were used to determine the association between Cd and standardized cognitive decline adjusting for covariates. The median blood Cd concentration of this study population was 2.12 µg/L, and the interquartile range was 1.42-4.64 µg/L. Significant association of higher Cd levels with lower cognitive scores were observed in five individual cognitive tests (Delayed Stick Design Test, Boston Naming Test, CERAD Word List Learning Test, Word List Recall Test and IU Story Recall Test) and the composite cognitive score adjusting for multi-covariates at baseline. Higher Cd levels were significantly associated with greater 3-year cognitive decline in Delayed Stick Design Test, Boston Naming Test, IU Token Test, Word List Recall Test and Composite cognitive score. For these cognitive tests, participants in the top two Cd quartile groups had significantly greater decline than those in the lowest Cd quartile group, while the two lowest Cd quartile groups were not significantly different. Our findings suggest that higher Cd exposure is associated with greater cognitive decline in older Chinese adults.

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Few studies have reported the quantitative association between heat and heatstroke (HS) occurrence, particularly in China. The aim of this study was to quantitatively assess the association between high temperature/heatwave and HS occurrence in Chongqing. The daily HS data from 2009 to 2013 of Chongqing were extracted from Chongqing Center for Disease Control and Prevention. A Zero-inflated Poisson regression model (ZIP) with a logistic distribution was used to quantitatively analyze the impacts of the daily maximum temperature (Tmax) over the threshold on HS occurrence by gender, age, and severity of HS, after controlling for covariates including day of the week (DOW), relative humidity, and daily temperature range. Lag effects up to 10 days were analyzed. Heatwave intensity, which was classified into four levels according to the quartile of its values, was calculated by Tmax multiplied the duration of a heatwave. The excess risk of HS during heatwave with different intensity was analyzed. The Tmax threshold for HS was 34 °C in Chongqing. After adjusting for potential confounders, strong associations and age-specific lag effects between Tmax and daily HS occurrence were observed. The impacts of Tmax on total HS lasted for 7 days (lag0-6), with the highest excess risk (ER) value of 30.5% (95% CI 23.6 and 37.8%) on lag0 with each 1 °C increment in Tmax over the threshold. A slightly stronger temperature-HS association was detected in male compared to female. The population over 65 years had the highest ER and the younger adults aged 19-35 and 35-55 years also showed significant heat-HS associations. The number of daily cases increased with the increasing of duration of heatwave and the peak value occurred on the eleventh day of the heatwave. The excess risk of HS during the heatwave with 1 to 4 level of intensity increased by 2.54, 2.97, 5.61, and 11.3 times, respectively, as compared with that of non-heatwave. Extreme heat is becoming a huge threat to public health due to the strong temperature-HS associations in Chongqing. Climate change with increasing temperatures may make the situation worse. Our results can provide reference for developing and improving relevant public health strategies and early extreme weather and health warning system to prevent and reduce the health risks due to extreme weather and climate change in Chongqing.

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OBJECTIVE: Higher selenium level has been hypothesized to have the potential to reduce the risk of cardiovascular diseases including dyslipidemia. However, results from previous studies are inconsistent. This study aims to determine the association between selenium level and dyslipidemia in elderly Chinese with relatively low selenium status. METHODS: A cross-sectional study of 1859 participants aged 65 or older from four rural counties in China was conducted. Serum total cholesterol (TC), triglycerides (TG), high density lipoprotein-cholesterol (HDLC) and low-density lipoprotein-cholesterol (LDLC), nail selenium concentration and APOE genotype were measured in all subjects. The four types of dyslipidemia were defined as >5.17 mmol/L for High-TC, >1.69 mmol/L for High-TG, >3.36 mmol/L for High-LDLC, and <1.04 mmol/L for Low-HDLC according to Chinese Guidelines on Prevention and Treatment of Dyslipidemia in Adults. Logistic models adjusting for age, gender, APOE genotype, body mass index, alcohol consumption, smoking, physical activity, medication use for cardiovascular diseases were used to examine the relationship between selenium levels and the risk of dyslipidemia. RESULTS: Mean nail selenium concentration was 0.465 µg/gin this sample. Rates for High-TC, High-LDLC, High-TG, Low-HDLC were 18.13%, 13.23%, 12.21% and 32.76% respectively. Results from logistic models indicated that higher selenium levels were significantly associated with higher risk of High-TC, High-LDLC and lower risk of Low-HDLC adjusting for covariates (p < 0.0001). Compared with the lowest selenium quartile group, participants in selenium quartile groups 2, 3 and 4 had significantly higher rates of High-TC, High-LDLC, High-TG, and lower rate of Low-HDLC adjusting for covariates. No significant association was observed between selenium level and the risk of High-TG. APOEε4 carriers had higher rates of High-TC and High-LDLC. There was no interaction between selenium level and APOE with the rates of dyslipidemia. CONCLUSIONS: Our results suggest long-term selenium exposure level may be associated with the risk of dyslipidemia in elderly population. Future studies are needed to examine the underlying mechanism of the association.

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OBJECTIVE: To measure serum levels of heavy metals in Chinese pregnant women and their newborns, and to evaluate the association of these metals with infant birth weight. STUDY DESIGN: We measured serum concentrations of lead (Pb), thallium (Tl), cadmium (Cd), selenium (Se), arsenic (As), nickle (Ni), vanadium (V), cobalt (Co), and mercury (Hg) in 81 mother-infant pairs using an inductively coupled plasma mass spectrometry method. Multiple linear regression analyses were used to evaluate the associations of these heavy metals with infant birth weight. RESULTS: Se, Pb, As, and Cd showed the highest detection rates (98.8%) in both the maternal and cord blood, followed by Tl, which was detected in 79.0% and 71.6% of the maternal and cord blood samples, respectively. Pb had the highest concentrations in both the maternal and cord blood samples of all toxic metals detected, with concentrations of 23.1 ng/g and 22.0 ng/g, respectively. No significant associations were observed between any heavy metals and birth weight. However, Tl in the maternal and cord blood was most notably inversely associated with birth weight. CONCLUSION: Se intake was low in Chinese women and their newborns, whereas Pb had the highest concentrations in both the maternal and cord blood samples of all toxic metals detected. Tl was a unique pollution source in this population, and Tl levels were shown to have the largest effect on decreasing infant birth weight in this pilot study. Further research incorporating larger sample sizes is needed to investigate the effects of prenatal exposure to heavy metals--especially Tl and Pb--on birth outcome in Chinese infants.

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OBJECTIVES: Examine the relationship between blood lead concentration and children's intelligence quotient (IQ) in Chinese children 8-12 years old. PARTICIPANTS AND METHODS: This is a cross-sectional study, and participants included 446 children from three primary schools in Jiangsu, China. We collected environmental and genetic information from questionnaires. Blood lead (Pb), manganese (Mn), cadmium (Cd) and selenium (Se) concentrations were measured using inductively coupled plasma mass spectrometry (ICP-MS). IQ was assessed using the Combined Raven's Test and then converted to a standard IQ score according to Chinese children's norm. Morning urine samples were collected to measure retinol binding protein (RBP). RESULTS: The average blood lead concentration was 33.13 µg L(-1) (geometric mean), and the blood lead concentration (BoxCox transform) was inversely and significantly associated with IQ (r=-0.11, p=0.02). The geometric mean of blood Mn, Cd and Se was 7.02 µg L(-1), 0.18 µg L(-1) and 94.77 µg L(-1), respectively. Blood Mn, Cd and Se showed no association with IQ, but all of them associated with urinary RBP. Urinary RBP was identified as a new factor associated with IQ (ß=-6.49, p=0.011). CONCLUSIONS: Urinary RBP was recognized as a new indicated factor associated with children's IQ. Mn, Cd and Se exposure might affect urinary RBP concentration and further IQ. Findings also support that blood lead concentrations in 8-12 years old children, even <44 µg L(-1), have a negative association with IQ.

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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.

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INTRODUCTION: Previous studies have identified hyperlipidemia as a potential risk factor for dementia and Alzheimer's disease. However, studies on cholesterol measured in late-life and cognitive function have been inconsistent. Few studies have explored nonlinear relationships or considered interactions with other biomarker measures. METHODS: A cross-sectional sample of 1,889 participants from four rural counties in the People's Republic of China was included in this analysis. Serum total cholesterol, high-density lipoprotein, triglycerides, and homocysteine levels were measured in fasting blood samples. A composite cognitive score was derived based on nine standardized cognitive test scores. Analysis of covariance models were used to investigate the association between biomarker measures and the composite cognitive scores. RESULTS: There was a significant interaction between the homocysteine quartile group and the cholesterol quartile group on cognitive scores (P=0.0478). In participants with normal homocysteine levels, an inverse U-shaped relationship between total cholesterol level and cognitive score was found, indicating that both low and high cholesterol levels were associated with lower cognitive scores. In participants with high homocysteine levels, no significant association between cholesterol and cognition was found. CONCLUSION: The relationship between cholesterol levels and cognitive function depends upon homocysteine levels, suggesting an interactive role between cholesterol and homocysteine on cognitive function in the elderly population. Additional research is required to confirm our findings in other populations, and to explore potential mechanisms underlying the lipid-homocysteine interaction.

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BACKGROUND: Numerous studies have reported the association between ambient temperature and mortality. However, few studies have focused on the effects of extreme temperatures on diabetes mortality, particularly in China. The objective of the present study was to assess the effects of extremely cold and hot temperatures on diabetes mortality in urban areas of Harbin and Chongqing in China to provide scientific evidence for public health policy implementation to respond to challenges in diabetes mortality because of extreme temperature events. METHODS: A double threshold B-spline distributed lag non-linear model (DLNM) was used to investigate the effects of extremely cold and hot temperatures on diabetes mortality from lag 0 to 30 days, after controlling for potential confounders including air pollutants. The unit risk, which is the elevated cumulative risk of diabetes mortality caused by each 1 °C change in extremely cold and hot temperatures during certain lag days, was estimated for extreme cold and heat using simple regression analysis. RESULTS: Significant associations between both extreme hot and cold temperatures and diabetes mortality were observed in Harbin and Chongqing for different lag lengths. In Harbin, the extreme cold effects on diabetes mortality were delayed by three days and lasted for six days (lag 3-8), with the highest risk (RR 95% CI: 1.223,1.054-1.418 for -23 °C) at lag 5. The hot effects were delayed one day and lasted for three days (lag 1-3), with the peak RR (1.343: 1.080-1.670 for 37 °C) at lag 2. In Chongqing, the cold effects on diabetes mortality were delayed by seven days and lasted for four days (lag 7-10), with the highest risk (1.201: 1.006-1.434 for 4 °C) at lag 7. The hot effects peaked (1.811: 1.083-3.027 for 41 °C) at lag 0 and lasted for 2 days (lag 0-1). The unit risk for cold and hot effects was 12.9% (95% CI: 2.5-33.7%) and 16.5% (95% CI: 3.8-39.1%) in Harbin and 12.5% (95% CI: -4.7 to 47.5%) and 19.7% (95% CI: 3.9-48.5%) in Chongqing, respectively. CONCLUSIONS: The results indicate that both extremely cold and hot temperatures increase diabetes mortality in different manners in Harbin and Chongqing. Diabetes education programs should include information on either managing or combating the effects of extreme hot and cold weather.

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BACKGROUND: Numerous studies have reported on the associations between ambient temperatures and mortality. However, few multi-city studies have been conducted in developing countries including China. This study aimed to examine the association between high temperature and mortality outcomes in four cities with different climatic characteristics in China to identify the most vulnerable population, detect the threshold temperatures, and provide scientific evidence for public health policy implementations to respond to challenges from extreme heat. METHODS: A semi-parametric generalized additive model (GAM) with a Poisson distribution was used to analyze the impacts of the daily maximum temperature over the threshold on mortality after controlling for covariates including time trends, day of the week (DOW), humidity, daily temperature range, and outdoor air pollution. RESULTS: The temperature thresholds for all-cause mortality were 29°C, 35°C, 33°C and 34°C for Harbin, Nanjing, Shenzhen and Chongqing, respectively. After adjusting for potential confounders including air pollution, strong associations between daily maximum temperature and daily mortality from all-cause, cardiovascular, endocrine and metabolic outcomes, and particularly diabetes, were observed in different geographical cities, with increases of 3.2-5.5%, 4.6-7.5% and 12.5-31.9% (with 14.7-29.2% in diabetes), respectively, with each 1°C increment in the daily maximum temperature over the threshold. A stronger temperature-associated mortality was detected in females compared to males. Additionally, both the population over 55 years and younger adults aged 30 to 54 years reported significant heat-mortality associations. CONCLUSIONS: Extreme heat is becoming a huge threat to public health and human welfare due to the strong temperature-mortality associations in China. Climate change with increasing temperatures may make the situation worse. Relevant public health strategies and an early extreme weather and health warning system should be developed and improved at an early stage to prevent and reduce the health risks due to extreme weather and climate change in China, given its huge population, diverse geographic distribution and unbalanced socioeconomic status with various climatic characteristics.

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In utero exposure to organochlorine pesticides (OCPs) is thought to be potentially harmful to fetal development. We aimed to investigate the associations of maternal and cord serum OCPs levels with infant birth weight in China. In this study, we measured serum levels of 18 OCPs in 81 mother-infant pairs, including DDT, hexachlorocyclohexanes (BHC), hexachlorobenzene (HCB), heptachlors, chlordanes, endosulfan-I, and mirex using a high-resolution-gas-chromatography with high-resolution-mass-spectrometry method. We found that p,p'-DDE and ß-BHC had the highest detection rate in both maternal and cord blood serum (97.2% and 96.7%, respectively), followed by HCB (93.0%, 51.7%), p,p'-DDT (88.7%, 36.7%), and p,p'-DDD (83.1%, 60.0%). Among all OCPs, the concentration of p,p'-DDE was the highest (mothers geometric mean (GM): 203.54ngg(-1), newborns GM: 116.14ngg(-1)), followed by HCB (70.62ngg(-1), 65.16ngg(-1)), and ß-BHC (67.67ngg(-1), 33.39ngg(-1)). Multiple linear regression analyses showed that each 1ngg(-1) increment of cord serum p,p'-DDE, total DDT, and ß-BHC was associated with a 0.10g, 0.10g, and 0.92g decrease in infant birth weight, respectively, and as the cord serum concentrations of p,p'-DDT, p,p'-DDD, HCB and mirex increased, the infant birth weight was also decreased, although the associations were not statistically significant due to the relatively small sample size. These results suggest that p,p'-DDE, ß-BHC, and HCB were the predominant OCPs in the serum of Chinese pregnant women and cord blood of their newborns. Prenatal exposure to DDT, ß-BHC, HCB, and mirex were associated with a decrease in birth weight, but these results need validation in larger sample-sized studies.

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To evaluate the current maternal and fetal exposure to cadmium (Cd), lead (Pb) and selenium (Se), and their potential effect on newborn birth outcomes, a cross-sectional study involving an assessment of the levels of these three metals in maternal blood, urine and umbilical cord blood was conducted in 209 pregnant women living in Eastern China. The maternal blood, urine and cord blood samples were collected and measured with inductively coupled plasma mass spectrometry (ICP-MS). The maternal blood concentrations of Cd, Pb and Se (the geometric means (GMs) were 0.48, 39.50 and 143.53 µg L(-1)) were significantly higher than and correlated with those in the cord blood (GM: 0.09, 31.62 and 124.61 µg L(-1)). In the urine samples, the GMs for Cd, Pb and Se were 0.13, 0.48, and 4.78 µg L(-1), respectively. Passive smoking was found to positively correlate with urine Cd (r=0.16) and negatively correlate with urine Se (r=-0.29). The maternal blood Se level was negatively associated with the cord Cd levels (r=-0.41). The blood Cd concentration in the mother could significantly affect the newborn birth weight (r=-0.22), but it was not correlated with birth height. We identified cord Se as a new factor which significantly correlated with birth weight. In conclusion, maternal Cd, Pb, Se exposure correlated with their umbilical cord concentration, and maternal Cd exposure might affect the newborn birth weight. Increasing the Se intake might reduce the cord blood Cd concentration and promote the fetal growth.

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BACKGROUND: Previous 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. METHODS: A 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. RESULTS: Of 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. CONCLUSIONS: Cognitive 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.

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Organochlorine pesticides can interfere with the thyroid hormones that play an important role in early neurodevelopment. Although organochlorine pesticides have been banned in China since 1983, their residues are still detectable in the environment. However, few studies have investigated the adverse health effects of prenatal exposure to organochlorine pesticide residues on newborns in China. The present study, conducted in Yancheng City, Jiangsu Province, China, aimed to examine the association between the levels of organochlorine pesticides in maternal and cord sera and to assess the impact of prenatal exposure to organochlorine pesticides on thyroid hormone levels in cord serum. Eleven organochlorine pesticides in maternal and cord sera were measured in 247 mother-infant pairs recruited from Yancheng City between February 2010 and June 2010. The concentration of the thyroid hormones free triiodothyronine (FT3), free thyroxine (FT4), and thyrotropin (TSH) were determined in cord serum. Among the 11 tested organochlorine pesticides, the detectable levels of hexachlorobenzene (HCB), ß-hexachlorocycolohexane (ß-HCH) and p,p'-dichlorodiphenyldichloroethylene (p,p'-DDE) in both maternal and cord sera were above 50%. The levels of ß-HCH and p,p'-DDE in maternal sera were positively associated with the levels in cord sera (r=0.421, P<0.01; r=0.288, P<0.01). After adjusting for confounders, the TSH level in cord serum samples was negatively associated with the HCB level (OR=0.535, 95% CI=(0.304-0.941)). Our data demonstrated that DDT, ß-HCH and HCB residues bioconcentrate in maternal and cord sera. Moreover, the correlation analysis suggested that organochlorine pesticides in maternal blood can transfer through the placenta and affect newborn thyroid hormone levels.

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OBJECTIVE: To study the gene expression patterns in livers of infant rats after Benzo[a]pyrene (BaP) exposure during pregnancy and explore the important gene and signaling pathways in the toxic mechanism of BaP. METHODS: Thirty-two pregnant SD rats were randomly divided into four groups: vehicle control (corn oil) and treatment groups (0.75, 1.50 and 3.00 mg/kg BaP in corn oil). BaP solutions were given by gastric infusion from the 3rd to the 17th day of pregnancy. After delivery the offspring's liver were taken to detect the gene expression by RatRef-12 gene chip. The stability of gene chip was tested by repeated experiments. RESULTS: After prenatal BaP exposure 1232 genes with different expression variations in hepatocytes of offsprings were identified. Three expression patterns of genes related to the dose of prenatal BaP exposure were identified with significant difference (P < 0.05). As the dose of prenatal BaP exposure increased, the gene expression patterns were downregulated, upregulated, and fluctuated. Twenty-six signaling pathways with differently expressed genes mainly focused on: growth and development, toxicant metabolism and inflammation (P < 0.05). The data from gene network analysis demonstrated that CYP2C13, GSTO1, Rela, MAPK8 and Plcg1 were the key genes in the gene network. CONCLUSION: Gene expression patterns of offsprings' hepatocytes were influenced by prenatal BaP exposure. Some key genes and signal pathways were also found. The study provides an important clue for the toxicity and mechanisms of the prenatal BaP exposure on the growth and development of offspring.

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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.

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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.

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