Effects of indoor exposure to low level toluene on neural network alterations during working memory encoding.

OBJECTIVE: While high concentrations of toluene are known to affect multiple human organ systems, research concerning the influence of immediate, short-term exposure to toluene indoors and at low concentrations is scarce. Here, we studied effects of indoor toluene exposure on neural network alterations during working memory (WM) encoding. METHODS: A total of 23 healthy college students were recruited. All participants were situated in a closed environmental chamber with a full fresh air system. Each participant was subjected to four exposure experiments with different toluene concentrations (0, 17.5, 35, and 70 ppb, named Group A, B, C and D, respectively), with at least one week between each experiment. WM Behavioral and 19-channel electroencephalogram (EEG) recordings in a pre-set environmental chamber were conducted simultaneously during each toluene exposure experiment. Neural networks relevant to WM encoding were visualized analyzing the obtained data. RESULTS: 1. No significant difference in WM behavioral performance among the four groups was found. However, a significant increase in whole brain neural network functional connectivity was noted, especially in the frontal region. 2. An outflow directional transfer function (DTFoutflow) revealed higher frontal region values among Group D (the 70 ppb group) as compared to Group A, B and C (the0, 17.5 ppb and 35 ppb groups, respectively), although no differences in frontal region DTFinflow values among the four groups were noted. 3. The DTFFZ-F7, DTFFZ-T5, DTFFZ-P4, DTFFZ-P3, DTFFP2-O2, DTFP3-T4, DTFP3-F4, DTFP4-CZ and DTFP4-T4 values of Group D were found to be higher as compared to those of Group A and B. Furthermore, DTFFZ-F7 and DTFP4-T4 values of Group C were higher as compared to those of Group A. The DTFFZ-F7 values of Group D were higher as compared to those of the Group C. CONCLUSION: Short-term toluene exposure significantly influences neural networks during cognitive processes such as WM encoding, even at low concentration.

Acute Gaseous Air Pollution Exposure and Hospitalizations for Acute Ischemic Stroke: A Time-Series Analysis in Tianjin, China.

BACKGROUND: Stroke has always been an important problem troubling human health. Short-term exposure to air pollutants is associated with increased hospital admissions. The rise of pollutants such as O3 has caused a huge social and economic burden. This study aims to explore the relationship between short-term exposure to ambient gaseous pollutants and daily hospitalizations for ischemic stroke, utilizing a four-year time-series study in Tianjin. METHODS: Collecting the data of gaseous pollutants (NO2, SO2, CO, O3), meteorological data (including daily average temperature and relative humidity) and the number of hospitalizations due to ischemic stroke in Tianjin Medical University General Hospital from 2013 to 2016. Poisson regression generalized additive model with single-day and multi-day moving average lag structure was used to estimate adverse effects of gaseous pollutants on daily hospitalizations. Subgroup analysis was performed to detect modification effect by gender and age. RESULTS: In total, there were 9081 ischemic stroke hospitalizations. After controlling for the meteorological factors in the same period, no significant findings were found with the increase of NO2, SO2, CO and O3 concentrations at most of the time in the single-pollutant model. Similarly, in the stratified analysis, no associations between gaseous pollutants and ischemic stroke were observed in this study. CONCLUSIONS: Short-term exposure to NO2, SO2, CO and O3 was not distinctly associated with daily hospitalizations for ischemic stroke in Tianjin. Multicenter studies in the future are warranted to explore the associations between gaseous pollution exposure and ischemic stroke.

Association of metabolic syndrome with carotid atherosclerosis in low-income Chinese individuals: A population-based study.

Background: This study aimed to explore the association of the presence and number of components of metabolic syndrome (MetS) with carotid atherosclerosis by measuring the presence of carotid plaque and total plaque area (TPA) in a population from a low-income area with high incidence of stroke of northern China. Methods: A cross-sectional study was conducted in a rural area of Tianjin, China from April 2014 to January 2015. The presence of plaque and TPA measurement was determined by carotid ultrasound. The presence and number of components of MetS was ascertained using the modified International Diabetes Federation criteria for the Asian population. Results: Among a total of 3,583 individuals aged ≥ 45 years, the overall prevalence of MetS was 54.5%. MetS and its components were related to the presence of carotid plaque as well as TPA. Multivariate analysis showed MetS was associated with a 20% higher risk of carotid plaque presence (95% confidence interval: 1.01, 1.42; P = 0.036) and an 18% increase in TPA (95% confidence interval: 0.08, 0.27; P < 0.001). The number of MetS components showed an increasing trend with the risk of carotid plaque presence and increased TPA. Among single components of MetS, high BP accounted for the largest proportion and was an independent risk factor of carotid plaque and increased TPA. Conclusions: Among individuals aged 45 years or more, we confirmed MetS and its components were associated with carotid atherosclerosis in a low-income population of northern China. The presence of MetS and a higher number of MetS components exacerbated the risk of carotid atherosclerosis; among the five MetS components, high blood pressure was associated with the greatest risk. Targeted atherosclerosis prevention and intervention should include identification and treatment of MetS, especially high blood pressure.

Alternations in neural oscillation related to attention network reveal influence of indoor toluene on cognition at low concentration.

Despite accumulative literature reporting negative impacts of high-concentration toluene, cognitive effects of toluene at low concentration are still unclear. Twenty-two healthy college students were exposed in a closed environmental chamber to investigate the influence of indoor toluene on cognitive performance and brain activity. During each toluene exposure condition (0 ppb, 17.5 ppb, 35 ppb, and 70 ppb), attention network test and electroencephalogram (EEG) recording were synchronously performed after 4-hour toluene exposure. Characteristic neural oscillation patterns in three attention networks were compared between four groups. The statistical analyses indicated that short-term exposure to toluene had no significant impact on behavioral performance of attention network. However, there was a significant increase in the power of theta and alpha band of executive network and orienting network in the whole brain, especially in frontal region when exposed to toluene. Besides, no significant difference was observed in alerting network. The alternations in neural oscillation demonstrated that more effort was required to accomplish the same tasks when exposed to toluene. The present study revealed that short-term exposure to toluene affected brain activity of attention network even at low concentration, which provided a theoretical basis for the development of safer evaluation methods and standards in the future.

Long-Term Trends in Stroke Management and Burden Among Low-Income Women in a Rural Area From China (1992-2019): A Prospective Population-Based Study.

Although an increasing number of studies are considering sex-related differences in stroke burden, the trends in stroke burden and management among women in China, especially among low-income women, remain unclear. This study evaluated the long-term trends in stroke management and burden among low-income Chinese women during the period between 1992 and 2019. Stroke burden was assessed using the age-adjusted incidence of first-ever stroke, whereas stroke management was assessed using the rates of neuroimaging diagnoses, hospitalizations, case fatalities, and stroke recurrence. Stroke burden and management were analyzed during four study periods: 1992-1998, 1999-2004, 2005-2012, and 2013-2019. During the 193,385 person-years of surveillance in this study, 597 female stroke patients were identified. The stroke incidences per 100,000 person-years were 88.1 cases during 1992-1998, 145.4 cases during 1999-2004, 264.3 cases during 2005-2012, and 309.8 cases during 2013-2019 (P < 0.001). Between 1992 and 2019, the incidence of stroke significantly increased (6.4% annually) as did the incidence of ischemic stroke (7.8% annually; both, P < 0.001). The rates of neuroimaging diagnoses and hospitalizations significantly increased during the four periods, while the case fatality rates and 1-year recurrence rates decreased significantly for both overall strokes and ischemic strokes, especially among patients ≥45 years old (all, P < 0.001). Among low-income women in China, stroke management is gradually improving, despite the increasing stroke burden. Thus, improved healthcare coverage is needed to further reduce the stroke burden among low-income Chinese women.

Sex Differences in the Association Between Obesity and Cognitive Impairment in a Low-Income Elderly Population in Rural China: A Population-Based Cross-Sectional Study.

Background: Obesity is a potentially modifiable risk factor for cognitive impairment. However, sex-specific relationships between obesity and cognitive impairment in late life remain unclear. Objective: We aimed to assess sex differences in the association between various obesity parameters and cognitive impairment in a low-income elderly population in rural China. Methods: A population-based cross-sectional study was conducted to collect basic information from elderly residents aged 60 years and older from April 2014 to August 2014 in rural areas of Tianjin, China. Obesity parameters, including body mass index (BMI) and waist circumference (WC), and Mini Mental State Examination scores were measured, and the relationships between these variables were assessed. Results: A total of 1,081 residents with a mean age of 67.70 years were enrolled in this study. After adjusting for age, educational attainment, smoking status, drinking status, physical exercise participation, and the presence of diabetes and hyperlipidemia, blood pressure group; a high BMI was found to be associated with an increased prevalence of cognitive impairment in elderly women. Each 1-unit increase in BMI was associated with a 5.9% increase in the prevalence of cognitive impairment. WC was related to the prevalence of cognitive impairment in elderly men, and each 1-cm increase in WC was associated with a 4.0% decrease in the prevalence of cognitive impairment. However, there were no significant associations between WC and cognitive function in women or between BMI and cognitive impairment in men. Conclusion: A greater WC was positively associated with better cognitive function in low-income elderly men in rural China, whereas a higher BMI was associated with an increased risk of cognitive impairment in elderly women, independent of sociodemographic, lifestyle, and health-related comorbid factors. Our results suggest weight management of elderly women in rural China may have cognitive benefits. However, randomized controlled trials would be needed to confirm causality.

Relationship Between Metabolic Syndrome and Cognitive Function: A Population-Based Study of Middle-Aged and Elderly Adults in Rural China.

INTRODUCTION: To explore the relationship between metabolic syndrome (MetS) and cognitive impairment in a low-income and low-education population. METHODS: All residents aged ≥45 years in a low-income population in Tianjin, China, were eligible to participate in this study. The Mini-Mental State Examination (MMSE) scale was used to conduct a preliminary screening and assessment of the participants' cognitive statuses. The MMSE components are orientation, registration, attention and calculation, recall, and language. RESULTS: In this population, the prevalences of MetS and cognitive impairment were 54.1% and 44.5%, respectively. In the overall population, the registration score was 0.105 points lower in the elevated triglycerides (TG) group than in the normal TG group (ß, -0.105; 95% confidence interval [CI]: -0.201, -0.010; P=0.030). In men, high TG was associated with registration scores that were 0.152 points lower than those in the normal TG group (95% CI: -0.281, -0.022; P=0.022), while larger WC and lower HDL-C had positive effects on cognitive scores (all P<0.05). However, in women, there were no significant differences between cognitive scores and MetS or its components. CONCLUSION: In this population, first, TG had a great impact on cognition, even greater than the impact of MetS on cognition. Second, the impact of MetS components on cognition was more obvious in men, and not all of the effects were negative. Therefore, the effect of MetS on cognition may need to be analyzed separately for different populations, and it may be that the effect of a single component is greater than the overall effect. When formulating prevention strategies for cognitive impairments, population differences must also be taken into consideration.

Carotid Intima-media Thickness and its Association with Conventional Risk Factors in Low-income Adults: A Population-based Cross-Sectional Study in China.

Carotid intima-media thickness (CIMT) is an established predictor of cardiovascular disease and stroke. However, risk factors associated with CIMT remain unclear. Therefore, we aimed to identify factors associated with CIMT in a low-income Chinese population. Stroke-free and cardiovascular disease-free residents aged ≥45 years were recruited. B-mode ultrasonography was performed to measure CIMT. The mean age of participants (n = 3789) was 59.92 years overall, 61.13 years in men, and 59.07 years in women (P < 0.001). Male sex, older age, low education level, smoking, hypertension, and high systolic blood pressure, fasting blood glucose, and low-density lipoprotein cholesterol levels were independent determinants of mean CIMT. Mean CIMT was higher by 18.07 × 10-3 mm in hypertensive compared to normotensive participants (P < 0.001), by 19.03 × 10-3 mm in men compared to women (P < 0.001), and by 9.82 × 10-3 mm in smokers compared to never smokers (P < 0.001). However, mean CIMT decreased by 1.07, 0.37, and 2.36 × 10-3 mm per 1-unit increase in education level, diastolic blood pressure, and triglycerides, respectively. It is important to manage conventional risk factors in low-income populations to decrease stroke incidence.

Prevalence and Risk Factors of Carotid Plaque Among Middle-aged and Elderly Adults in Rural Tianjin, China.

Carotid plaque (CP) is associated with cardiovascular and cerebrovascular events. However, population-based studies with a large sample are rare in China, particularly those in the low-income population. We aimed to determine the prevalence of CP and the associated risk factors in the rural areas of northern China. Between April 2014 and June 2014, we recruited 3789 residents aged ≥45 years. B-mode ultrasonography was performed to measure the extent of CP. The prevalence of CP was 40.3% overall, 47.1% in men, and 35.4% in women (P < 0.001). The prevalence of CP increased with increasing age (P < 0.001). The participants with CP were more likely to have hypertension, diabetes, high total cholesterol (TC) levels, and high low-density lipoprotein-cholesterol levels and be a current smoker; however, they were less likely to be obese. Multiple logistic regression analysis, adjusted for confounders, indicated that age, male sex, hypertension, diabetes, current smoking, and high LDL-C levels were the independent risk factors for CP. There was a lower risk of CP with alcohol consumption. The findings suggest that managing the conventional risk factors is crucial to reduce the burden of cardiovascular and cerebrovascular diseases in the low-income population in China.

Cardiovascular Risk Factors Among Low-Income Women: A Population-Based Study in China from 1991 to 2011.

BACKGROUND: Data on long-term trends in the prevalence and clustering of cardiovascular disease (CVD) risk factors among women in China are rare, especially among low-income women. The aim of this study was to investigate the secular trends in the prevalence of CVD risk factors among low-income women in northern China. MATERIALS AND METHODS: The prevalence and clustering of CVD risk factors, including hypertension, diabetes, obesity, current smoking status, and alcohol consumption, were assessed and compared in women aged 35-74 years in northern China in 1991 and 2011. RESULTS: The age-adjusted prevalence of cardiovascular risk factors among women was significantly higher in 2011 than in 1991, with increases of 31% (53.6% vs. 41.1%) for hypertension, 148% (20.9% vs. 8.4%) for obesity, 256% (11.7% vs. 3.3%) for diabetes, and 1634% (4.5% vs. 0.3%) for alcohol consumption. Over the 21-year period, there were significant differences in the prevalence of clustering of ≥1, ≥2, and 3 risk factors in all age groups. The greatest increase was observed among women aged 35-44 years, with a 7.3-fold increase in the prevalence of clustering of three risk factors. Simultaneously, the prevalence of clustering of ≥1 risk factors among women aged 35-44 years was 1.7-fold higher in 2011 than in 1991; the prevalence of clustering of ≥2 risk factors was raised by 5.5-fold among elderly women. CONCLUSIONS: Our findings suggest that it is crucial to emphasize the prevention and control of cardiovascular risk factors among young women in rural China to reduce the burden of CVDs.

Trends in Age of First-Ever Stroke Following Increased Incidence and Life Expectancy in a Low-Income Chinese Population.

BACKGROUND AND PURPOSE: We investigated secular trends in the age of stroke onset and stroke incidence in a low-income population in rural China. METHODS: The study population was recruited from a population-based stroke surveillance study conducted in a township in Tianjin, China, from 1992 to 2014. The trends in mean age and incidence of first-ever stroke were assessed by sex and stroke subtype. Risk factor surveys were conducted in the same population in both 1991 and 2011. RESULTS: A total of 1053 patients experienced first-ever stroke from 1992 to 2014. The mean age of stroke onset in men significantly decreased by 0.28 years annually overall, by 0.56 years for intracerebral hemorrhage, and by 0.22 years for ischemic stroke (P<0.05). However, a similar trend was not observed in women. The age-standardized first-ever stroke incidence in the same population significantly increased across sex and stroke subtypes, increased by 6.3% overall, 5.5% for men, 7.9% for women, 4.6% for intracerebral hemorrhage, and 7.3% for ischemic stroke (P<0.05) during 1992 to 2014. Concurrently, the prevalence of hypertension, diabetes mellitus, obesity, current smoking, and alcohol consumption increased significantly in young and middle-aged adults from 1991 to 2011. CONCLUSIONS: The age of stroke onset tends to be younger among low-income population in China after the dramatic increased incidence of stroke during the gradual extension of life expectancy of population in China. These findings suggested that stroke burden will continue to increase in the long time, unless the risk factors in low-income populations are effectively controlled.

Increasing stroke incidence and prevalence of risk factors in a low-income Chinese population.

OBJECTIVE: We investigated secular trends in incidence of first-ever stroke and the prevalence of stroke risk factors within the same population in rural China. METHODS: In 1985, 15,438 residents from a township of Tianjin, China, were recruited to the Tianjin Brain Study, a population-based stroke surveillance study. Stroke events and all deaths were registered annually. Because imaging technology was first available in 1992, we analyzed the incidence of first-ever stroke over 3 study periods-1992-1998, 1999-2005, and 2006-2012-from 1992 to 2012. Risk factor surveys were conducted in 1991 and 2011. RESULTS: The age-standardized incidence of first-ever stroke per 100,000 person-years increased rapidly from 124.5 in 1992-1998 to 190.0 in 1999-2005 and to 318.2 in 2006-2012; incidence increased annually by 6.5% overall and by 12% among men aged 45-64 years (p < 0.05). From 1992 to 2012, the age at first-ever stroke in men was earlier by 3.3 years overall, but a similar trend was not observed in women. Concurrently, the prevalence of high fasting glucose and alcohol consumption increased significantly in both men and women, especially in men aged <45 years; the prevalence of obesity and high fasting glucose increased by 8.8-fold and 11-fold, respectively, from 1992 to 2012. CONCLUSIONS: The incidence of stroke in rural China increased rapidly, particularly among middle-aged adults, along with a concurrent increase in risk factor prevalence. These findings suggest that without controlling these risk factors, stroke incidence will continue to increase over future decades in China.

Secular trends in prevalence of overweight and obesity among adults in rural Tianjin, China from 1991 to 2011: a population-based study.

OBJECTIVES: Obesity is associated with cardiovascular diseases and has become the main public health issue in western countries and urban China. However, the prevalence and secular trends of obesity in rural China are currently unknown. The aim of this study was to investigate secular trends in the prevalence of overweight and obesity among rural adults in northern China between 1991 and 2011. METHOD: The prevalence of overweight and obesity was assessed in adults aged 35-74 years living in a rural area in northern China by comparing two surveys that were conducted in 1991 and 2011, respectively. RESULT: The age-adjusted prevalence of overweight increased from 24.5% in 1991 to 42.0% in 2011, and the prevalence of obesity increased from 5.7% in 1991 to 19.6% in 2011. Over the 21-year period, there were significant increases in the prevalence of overweight and obesity for both men and women in all age groups; however, the greatest increase was observed in men aged 35-44 years, with an 10.3-fold increase in obesity prevalence. The prevalence of obesity increased significantly in all risk factors categories, including education levels, blood pressure categories, diabetes previous history, current smoking situation and alcohol drinking situation over the past 21 years overall (p<0.05). The greatest increase in obesity prevalence appeared among those who consumed alcohol (increased by 8.0-fold). Next, there was a 5.3-fold increase in the prevalence of obesity in illiterate residents. CONCLUSION: The prevalence of overweight and obesity has increased rapidly among rural adults in Tianjin over the past 21 years, with the most dramatic increase observed in young men. Therefore, the burden of obesity should serve as a call for action.

Sex differences in trends of incidence and mortality of first-ever stroke in rural Tianjin, China, from 1992 to 2012.

BACKGROUND AND PURPOSE: Sex differences in secular trends of stroke incidence are rarely reported. We aimed to explore sex differences in incidence and mortality of stroke in rural China from 1992 to 2012. METHODS: In 1992, 14 920 residents were recruited to participate in the Tianjin Brain Study, a population-based study on stroke surveillance. Stroke events and all deaths were annually registered. RESULTS: We observed 908 incident strokes (366 in women) from 1992 to 2012. Women were significantly younger than men (64±12 versus 68±11 years) in 1992 to 1998 (P=0.024). The incidence of first-ever stroke per 100 000 person-years for men was 166 in 1992 to 1998, 227 in 1999 to 2005, and 376 in 2006 to 2012; for women, the rates were 86 (1992-1998), 148 (1999-2005), and 264 (2006-2012). From 1992 to 2012, the incidence grew annually by 5.8% in men and 8.0% in women. The male/female incidence ratio declined significantly: 1.9 in 1992 to 1998, 1.5 in 1999 to 2005, and 1.4 in 2006 to 2012. There were no significant sex differences in mortality. The prevalence of obesity and diabetes mellitus, the levels of total cholesterol and triglycerides, and the age of menopause and reproductive years in women concurrently increased in 2011. CONCLUSIONS: There was a significant increase in the incidence of first-ever stroke in women annually and a declining trend in the male/female rate ratio in rural China during the past 21 years. These results suggest that stroke will become one of the major diseases affecting women in future decades in China.

Development of real-time assays for impedance-based detection of microbial double-stranded DNA targets: optimization and data analysis.

A real-time, label free assay was developed for microbial detection, utilizing double-stranded DNA targets and employing the next generation of an impedimetric sensor array platform designed by Sharp Laboratories of America (SLA). Real-time curves of the impedimetric signal response were obtained at fixed frequency and voltage for target binding to oligonucleotide probes attached to the sensor array surface. Kinetic parameters of these curves were analyzed by the integrated data analysis package for signal quantification. Non-specific binding presented a major challenge for assay development, and required assay optimization. For this, differences were maximized between binding curve kinetic parameters for probes binding to complementary targets versus non-target controls. Variables manipulated for assay optimization included target concentration, hybridization temperature, buffer concentration, and the use of surfactants. Our results showed that (i) different target-probe combinations required optimization of specific sets of variables; (ii) for each assay condition, the optimum range was relatively narrow, and had to be determined empirically; and (iii) outside of the optimum range, the assay could not distinguish between specific and non-specific binding. For each target-probe combination evaluated, conditions resulting in good separation between specific and non-specific binding signals were established, generating high confidence in the SLA impedimetric dsDNA assay results.