Effects of pre- and postnatal polychlorinated biphenyl exposure on metabolic rate and thyroid hormones of white-footed mice

Energy budgets have proven to be a valuable tool for predicting life history from physiological data in terrestrial vertebrates, yet these concepts have not been applied to the physiological effects of contaminants. Contaminants might affect energy budgets by imposing an additional metabolic cost or by reducing the overall amount of energy taken in; either process will reduce the energy available for production (i.e., growth or reproduction). This study examined whole animal energetic effects of polychlorinated biphenyl (PCB) exposure in white-footed mice (Peromyscus leucopus). Exposure to PCBs is known to reduce concentrations of plasma thyroid hormones, and thyroid hormones exert strong control over the rate of energy metabolism in mammals. Peromyscus leucopus that were proven breeders were fed PCBs in their food at 0, 10, and 25 ppm. Through lactation, offspring were exposed to PCB from conception and were maintained on the maternal diet to adulthood. No effects were seen on energy metabolism (O2 consumption, measured in adulthood) or on growth, but there were large dose-dependent decreases in thyroid hormone concentrations, particularly T4. The apparent disparity in our data between unchanged metabolic rates and 50% reductions in T4 concentrations can be rationalized by noting that free T3 (the fraction not bound to plasma protein) in treated mice was not significantly different from controls and that metabolism is most strongly influenced by free T3. Overall, this study did not demonstrate any energetic consequences of PCB exposure in P. leucopus at dietary concentrations up to 25 ppm.     

The influence of pre- and postnatal caloric intake on colon carcinogenesis

Mother rats were allowed to litter under conventional conditions. They were fed a complete, semipurified diet during gestation, and at time of littering the numbers of pups were reduced to either eight per litter or four per litter in two additional groups. At weaning, all rats were continued on the same diet that their mothers had consumed. One group of those reduced to four per litter at birth was allowed to continue to eat ad libitum while the other group, reduced to four per litter, was pair fed to the ad libitum eight per litter group. The group reduced to four per litter at birth and allowed to eat ad libitum during postnatal life gained the most weight and were heaviest at the termination of the study. This group also had the greater incidence and frequency of colon tumors when exposed to dimethylhydrazine (DMH). The group pair fed to rats fed conventional diets, eight rats per litter, had an incidence and frequency of tumors between the other two groups. These data demonstrate that early exposure to excess calories increased risk for cancer and that early and late excess caloric intake further increased risk. Thus, pre- and perinatal caloric intake may have a significant influence on susceptibility to cancer later in life. Mechanisms are only speculative but may include differences in metabolism and modulation of hormonal balance.     

代谢综合征与危险因素的相关研究论文可视化分析

目的 分析国际和国内代谢综合征与危险因素相关研究的热点与前沿,为国内研究者提供参考。方法 在Web of Science和CNKI两大数据库中以“代谢综合征”(“metabolic syndrome”)和“危险因素”(“risk factor”)为主题词,检索1998年至2017年发表的相关文献,利用Citespace V软件进行可视化分析。结果 近20年来,国际上关于代谢综合征与危险因素的论文数量呈先上升后下降趋势;而国内则呈先上升后进入平台期且缓慢下降的趋势。国际上的研究热点早期为实验室指标和相关疾病,后期转为公共卫生人群大数据;国内的早期研究热点也是实验室指标,后转为相关疾病和统计学方法。国际上核心作者呈百花齐放但又相互紧密联系的状态,而国内核心作者则缺乏联系。结论 近20年来,国内在该领域的研究论文数量并不少,但关于全国范围的公共卫生方面的研究不多,且缺乏省份、研究机构间的合作。     

The impact of metabolic syndrome on mental health-related quality of life and depressive symptoms

Quality of Life Research - Results examining associations between metabolic syndrome (MetS) and depression, as well as on quality of life (QoL), are inconsistent. We aimed to determine whether...     

Effect of pre- and postnatal essential fatty acid deficiency on brain development and myelination.

Pregnant mice were fed an essential fatty acid (EFA) deficient diet from day 1 of gestation. Several biochemical parameters of postnatal brain growth and myelination were measured on their progeny and compared with controls fed a normal diet containing 4% corn oil or a commercial breeder diet. Measurements of brain DNA, RNA and protein content of the EFA deficient mice suggested a retardation of brain growth and development of about 1 week compared to controls, with the most striking differences noted at ages below 15 days. DNA content of both control and experimental mice became comparable at 20 to 22 days but brain protein and RNA content remained lower in deficient mice at all ages studied. The levels of several myelin specific constituents were also measured in experimental and control brains. The brain galactolipid content was severely depressed at levels 21% of controls at 40 days of age. Proteolipid protein was also significantly reduced (23% of controls at 40 days of age). In contrast, the activity of the myelin marker enzyme, 2',3'-cyclic nucleotide-3'-phosphodiesterase, appeared to be totally unaffected by EFA deficiency. The results indicate that pre-and postnatal EFA deficiency results in a retardation of brain development and a profound reduction of some but not all myelin specific components.     

Heritability of the risk factors characteristic for the metabolic syndrome: a twin study

Both genetic and environmental factors play role in the pathogenesis of the metabolic syndrome. The magnitude of genetic and environmental influences on the components of metabolic syndrome may vary in different populations. Aims: The present study was aimed to determine the effects of genetic and environmental factors on risk factors characteristic for the metabolic syndrome. Methods: A total of 101 (63 monozygotic and 38 dizygotic) adult twin pairs (n=202; mean age: 43.3±15.8 years) were investigated. Medical history was recorded and physical examination was carried out for each subject. Fasting venous blood samples were used for measuring laboratory parameters. The presented estimates include the heritability structural equation (A-C-E) model results. In Model-1, all presented parameters are age- and gender- corrected. In Model-2, parameters were corrected for age, gender, body mass index and waist circumference. Results: Heritability in waist circumference (as well as in other anthropometric parameters such as weight and height) was high (Model-1: 71.0-88.1%). Similarly, genetic factors had the highest proportion of total phenotypic variance in systolic and diastolic blood pressure (Model-2: 57.1% and 57.7%, respectively). Based on the results of Model-2, unique environmental factors dominate alterations in serum triglycerides values (55.9%) while shared environmental factors proved to be substantial in alterations of HDL-cholesterol and fasting blood glucose values (58.1% and 57.1%, respectively). Comparing the results of Model-1 and Model-2, the difference in A-C-E model varied from 0.0% to 17.1%, indicating that only a minor proportion of genetic and environmental influences can be explained by the effects of anthropometric parameters. Conclusions: Among adult Hungarian healthy people, genetic factors have substantial influence on waist circumference and blood pressure values while environmental factors dominate alterations in serum triglycerides, HDL-cholesterol and fasting blood glucose values. The different heritability of individual risk factors challenges the original unifying concept of the metabolic syndrome. The results may be useful for establishing and implementing primary cardiovascular prevention both at individual and population levels.     

The impact of legalized abortion on child health outcomes and abandonment. Evidence from Romania

We use household survey data and a unique census of institutionalized children to analyze the impact of abortion legalization in Romania. We exploit the lift of the abortion ban in December 1989, when communist dictator Ceausescu and his regime were removed from power, to understand its impact on children's health at birth and during early childhood and whether the lift of the ban had an immediate impact on child abandonment. We find insignificant estimates for health at birth outcomes and anthropometric z-scores at age 4 and 5, except for the probability of low birth weight which is slightly higher for children born after abortion became legal. Additionally, our findings suggest that the lift of the ban had decreased the number of abandoned children.     

Assessment of pre- and postnatal exposure to polychlorinated biphenyls: lessons from the Inuit Cohort Study

Polychlorinated biphenyls (PCBs) are food-chain contaminants that have been shown to induce adverse developmental effects in humans. In the course of an epidemiologic study established to investigate neurodevelopmental deficits induced by environmental PCB exposure in the Inuit population of northern Québec (Nunavik, Canada), we compared three biomarkers of prenatal exposure and models to predict PCB plasma concentration at 6 months postpartum. Concentrations of 14 PCB congeners were measured by high-resolution gas chromatography with electron capture detection in lipids extracted from maternal plasma, cord plasma, breast milk (collected at approximately 1 month postpartum), and 6-month-old infant plasma samples. Similar congener profiles were observed in all biologic samples, and PCB-153, the most abundant and persistent PCB congener, was strongly correlated with other frequently detected PCB congeners in all biologic media. When expressed on a lipid basis, maternal plasma, cord plasma, and milk concentrations of this congener were strongly intercorrelated, indicating that PCB concentration in any of these biologic media is a good indicator of prenatal exposure to PCBs. A multivariate model that included maternal PCB-153 plasma lipid concentration, breast-feeding duration, and the sum of two skin-fold thicknesses (an index of infant body fat mass) explained 72% of PCB-153 plasma concentration variance at 6 months postpartum (p < 0.001). By contrast, based on the product of breast-feeding duration times the concentration of PCBs in plasma lipids, which was used as an index of postnatal PCB exposure in several studies, only 36% of infant plasma concentration was explained.     

The metabolic syndrome: recognition and management.

The National Cholesterol Education Program defines the metabolic syndrome as three or more of five abnormalities: waist circumference of >40 in (102 cm) for men or >35 in (88 cm) for women, triglyceride level of > or =150 mg/dL, high-density lipoprotein cholesterol of <40 mg/dL in men or <50 mg/dL in women, blood pressure of > or =130 or > or =85 mm Hg, and fasting glucose of > or =110 mg/dL. It is related to insulin resistance, but the two terms are not synonymous. Both are associated strongly with obesity. The metabolic syndrome is important as an indicator of increased risk of cardiovascular disease (CVD) in patients with and without clinical CVD. The CVD risk of the metabolic syndrome is greater than that conferred by any single CVD risk factor. Since risk factors tend to cluster, if one component of the metabolic syndrome is present, one should assess for other risk factors. The metabolic syndrome is also predictive of new-onset type 2 diabetes. Early diagnosis provides justification for measures that can improve components of the syndrome and reduce CVD risk. The management strategy for metabolic syndrome focuses on overall CVD risk rather than single risk factors; effective therapy includes priority for weight reduction and increased physical activity. Pharmacotherapy is typically needed for control of high blood pressure, hypercoagulability, and increased levels of blood glucose and triglycerides.     

营养干预对肥胖伴代谢综合征人群相关指标的影响

目的观察营养干预对肥胖伴代谢综合征人群体成分、血生化指标及血压的改善作用,探讨健康减重的方式。方法体质指数（BMI）≥28．0kg／m^2;男性腰围≥85cm、女性腰围≥80cm;伴有血脂、血压及血糖任两项检查异常的体检肥胖伴代谢综合征患者40例自愿参与本研究,观察营养干预两个月后参与者干预前后体成分、血脂、血糖、血压等指标的变化。统计分析采用SPSS18．0统计软件,计量资料以x^-±s表示,干预前后对比采用配对t检验。结果营养干预进行2个月后参与者体重、体脂肪量、BMI、内脏脂肪面积和腰臀比与干预前比较差异有统计学意义（t=17．02、11．07、5．11、10．35、9．58,P〈0．05）;营养参与者的干预前和干预后丙氨酸氨基转移酶、天冬氨酸氨基转移酶、胆固醇、三酰甘油、空腹血糖、收缩压和舒张压比较差异均有统计学意义（t=2．87、2．91、3．33、2．24、2．56、5．74、6．99,P〈0．05）。结论营养干预的方法通过减重,降低体内脂肪含量,对肥胖患者的血压、血糖和血脂异常有着明显的改善效果,从而降低因肥胖造成的胰岛素抵抗。     

藏族牧民代谢综合征的流行状况及相关因素

目的:研究青海省从高海拔牧区搬迁定居城镇的藏族牧民中MS的流行状况及相关因素,尤其是膳食因素。方法:采用横断面研究,纳入920名藏族成年人（男性419名,女性501名）,进行一般情况问卷调查、膳食频率调查、体格检查和生化检测。问卷调查包括社会经济、生活方式和食物消费指标。采用主成分分析鉴定膳食模式,采用logistic...     

The impact of socioeconomic status on the incidence of metabolic syndrome in a Taiwanese health screening population

Objectives

The purpose of this study was to estimate the incidence of metabolic syndrome (MS) in a 5-year follow-up adult population in Taiwan who were examined at the Major Health Screening Center, and to assess possible socioeconomic determinants of the syndrome in this sample.

Methods

The longitudinal study included 9,389 adults, aged 35?C74?years, who visited the Major Health Screening Center from 1998?C2002, and were followed up for 5?years.

Results

The 5-year cumulative incidence of MS in this sample was 11.37%, and the weighted incidence was 12.46%; 14.95% for men and 9.89% for women, respectively. After adjustment for behavioral and habits, family history, gender and age, education level was associated with the incidence of MS. With middle school and lower as a baseline, the incidence of MS for high school, junior college, and college and above was OR 0.80, 95% CI 0.64?C1.00; OR 0.80, 95% CI 0.62?C1.03 and OR 0.65, 95% CI 0.50?C0.83, respectively.

Conclusions

The standardized cumulative incidence of MS was 12.46%. Lower education level was an important socioeconomic determinant of MS in women.     

Effects of pre- and postnatal exposure to chlorinated dioxins and furans on human neonatal thyroid hormone concentrations.

Animal studies have shown that dioxins influence plasma thyroid hormone concentrations. To investigate the effect of chlorinated dioxins and furans on thyroid hormone concentrations in humans, we studied 38 healthy breast-fed infants. The study population was divided into two groups according to the dioxin concentrations in milk fat of their mothers. Blood samples were taken at birth and at the ages of 1 and 11 weeks. At birth a tendency to higher total thyroxine (tT4) concentrations was found in the high exposure group. At the ages of 1 and 11 weeks the increase of mean tT4 concentrations and tT4/thyroxine-binding globulin ratios in the high exposure group reached significance as compared to the low exposure group. At birth and 1 week after birth, mean thyrotropin (TSH) concentrations were similar in both groups, but at the age of 11 weeks the mean TSH concentrations were significantly higher in the high exposure group. We postulate that the observed plasma tT4 elevation in infants exposed to dioxins before and after birth is the result of an effect on the thyroid hormone regulatory system.     

The impact of the physical and urban environment on mental well-being

OBJECTIVES: To examine the strength of association between physical and social factors in the built environment and mental well-being, and to determine which factors are the most important. STUDY DESIGN: A postal survey based on a theoretical model of domains that might link the physical and urban environment with mental well-being was sent to 2696 adults aged 18 years or over, in four areas of Greenwich, London. Mental health was measured using the SF36 subscales for mental health (MH) and vitality (V). Additional household and area level data were appended for each respondent from a range of sources. RESULTS: 1012 questionnaires were returned (38% response rate). At the univariate level significant confounders that were associated with poorer mental well-being were being female, 85+ years, unemployed or retired, on housing benefit, council tenant, two or more children, and having requested re-housing Better mental well-being was associated with being aged 65 years to 84 years (better MH and V). Within domain analysis, adjusting for each of the confounding factors, resulted in the following factors being significantly associated with being in the lowest quartile for MH score: (i) control over the internal environment (damp), (ii) design and maintenance (not liking the look of the estate/road, (iii) noise (neighbour noise), (iv) density and escape (feeling over-crowded in the home, being dissatisfied with green spaces, dissatisfied with social and entertainment facilities) being dissatisfied with community facilities (such as libraries and community centres) was only significant for vitality, (v) fear of crime and harassment (feeling unsafe to go out in the day, feeling unsafe to go out at night, agreeing that needles and syringes left lying around are a problem) (vi) social participation (not enough events to get people together, not enough places to stop and chat). When these 12 factors were entered into a single model with the significant confounders five remained significantly associated with being in the lowest quartile for MH or V: neighbour noise MH OR 2.71 [95% CI 1.48, 4.98]; feeling over-crowded in the home MH OR 2.22 [1.42, 3.48]; being dissatisfied with access to green open spaces MH OR 1.69 [1.05, 2.74]; access to community facilities V OR 1.92, [1.24, 3.00]; feeling unsafe to go out in the day MH OR 1.64 [1.02, 2.64]; V OR 1.58 [1.00, 2.49]. CONCLUSIONS: This study confirms an association between the physical environment and mental well-being across a range of domains. The most important factors that operate independently are neighbour noise, sense of over-crowding in the home and escape facilities such as green spaces and community facilities, and fear of crime. This study highlights the need to intervene on both design and social features of residential areas to promote mental well-being.     

The impact of spousal bereavement on hospitalisations: Evidence from the Scottish Longitudinal Study

This paper estimates the impact of spousal bereavement on hospital inpatient use for the surviving bereaved by following the experience of 94,272 married Scottish individuals from 1991 until 2009 using a difference‐in‐difference model. We also consider the sample selection issues related to differences in survival between the bereaved and non‐bereaved using a simple Cox Proportional‐Hazard model. Before conducting these estimations, propensity score approaches are used to re‐weight the non‐bereaved to generate a more random‐like comparison sample for the bereaved. We find that those bereaved who survive are both more likely to be admitted and to stay longer in hospital than a comparable non‐bereaved cohort. Bereavement is estimated to induce on average an extra 0.24 (95% CI [0.15, 0.33]) hospital inpatient days per year. Similar to previous studies, we estimate the bereaved have a 19.2% (95% CI [12.5%, 26.3%]) higher mortality rate than the comparable non‐bereaved cohort.     

The impact of patient cost-sharing on low-income populations: Evidence from Massachusetts

Greater patient cost-sharing could help reduce the fiscal pressures associated with insurance expansion by reducing the scope for moral hazard. But it is possible that low-income recipients are unable to cut back on utilization wisely and that, as a result, higher cost-sharing will lead to worse health and higher downstream costs through increased use of inpatient and outpatient care. We use exogenous variation in the copayments faced by low-income enrollees in the Massachusetts Commonwealth Care program to study these effects. We estimate separate price elasticities of demand by type of service. Overall, we find price elasticities of about −0.16 for this low-income population — similar to elasticities calculated for higher-income populations in other settings. These elasticities are somewhat smaller for the chronically sick, especially for those with asthma, diabetes, and high cholesterol. These lower elasticities are attributable to lower responsiveness to prices across all categories of service, and to some statistically insignificant increases in inpatient care.