The Belgian PCB/dioxin incident: analysis of the food chain contamination and health risk evaluation

The Belgian PCB incident occurred at the end of January 1999 when a mixture of polychlorinated biphenyls (PCBs) contaminated with dioxins was accidentally added to a stock of recycled fat used in the production of animal feeds. Although signs of poultry poisoning were noticed by February, 1999, the source and the extent of the contamination were discovered only in May 1999, when it appeared that more than 2500 farms could have been supplied with contaminated feeds. This resulted in a major food crisis, which rapidly extended to the whole country and could be resolved only by the implementation of a large PCB/dioxin food monitoring program. Screening for PCB contamination was based on the determination of the seven PCB markers. When PCB concentrations exceeded the tolerance levels of 0.1 (milk), 0.2 (poultry, bovine, and pig meat), or 1 (animal feed) microg/g fat, dioxins (17 PCDD/Fs congeners) were also determined. At the end of December 1999, the database contained the results of more than 55,000 PCB and 500 dioxin analyses. The study of PCB levels and profiles in contaminated feeds delivered to poultry or pig farms confirmed that the Belgian PCB incident was due to a single source of PCB oil introduced into the food chain at the end of January 1999. This PCB oil had a congeners pattern closely matched to a mixture of Aroclor 1260/1254 in the proportion 75/25. The total amount of PCBs added to recycled fats was estimated at 50 kg (sum of the seven markers) or approximately 150 kg total PCBs, which corresponds to about 100 liters of PCB oil. This PCB mixture contained about 1g TEQ dioxins (more than 90- contributed by PCDFs) and about 2g TEQ dioxin-like PCBs. The proportions of PCB 52 and 101 congeners were fairly constant in animal feeds, excluding the possibility of secondary contamination due to fat recycling from contaminated animals. The highest concentrations of PCBs and dioxins were found in poultry and especially in the reproduction animals (hens and chicks), which showed the classical manifestations of chick edema disease. The pigs were also affected but to a lesser extent and no sign of intoxication was observed. The study of PCB/dioxin patterns and of the PCB:dioxin ratios revealed major differences in the metabolism of these compounds by farm animals. Whereas the PCBs:dioxins ratio was fairly constant in all poultry products with a mean value similar to that found in contaminated feeds (50,000), in pigs this ratio was both much higher and more variable (values up to 10,000,000), reflecting a faster elimination of dioxins than PCBs in these animals. These metabolic differences also emerged from the PCB and dioxin patterns which were altered much more in pigs than in poultry. Although the most contaminated food products (chicken meat) had PCB and dioxin levels more than 100 times above maximal recommended values, it is unlikely that this incident could have caused adverse effects in the general population of Belgium. A doubling of the PCB and dioxin burden of the young adult population would require the consumption of, respectively, 10 and 20 highly contaminated meals. In view of the very limited proportion of the poultry chain effectively contaminated during the incident (around 2%), such an extreme scenario was quite improbable for the general population except perhaps for farmers consuming their own products. But even in that case, it would have meant going back to the levels in the 1980s or attaining the body burden of subjects regularly eating contaminated seafood.     

Vaccine effectiveness against infection and onwards transmission of COVID-19: Analysis of Belgian contact tracing data,January-June 2021

In Belgium, high-risk contacts of an infected person were offered PCR-testing irrespective of their vaccination status. We estimated vaccine effectiveness (VE) against infection and onwards transmission, controlling for previous infections, household-exposure and temporal trends. We included 301,741 tests from 25 January to 24 June 2021. Full-schedule vaccination was associated with significant protection against infection. In addition, mRNA-vaccines reduced onward transmission: VE-estimates increased to >90% when index and contact were fully vaccinated. The small number of viral-vector vaccines included limited interpretability.     

The potential impact of health care reform on public health HIV-related activities.

This article observes that, despite the clear potential benefits of health care reform's expanding health insurance coverage for people with human immunodeficiency virus (HIV) disease, there is a real danger of losing existing acquired immunodeficiency syndrome (AIDS) services if federal categorical public health programs are cut. It discusses the considerable accomplishments of the Ryan White CARE Act and of Centers for Disease Control and Prevention (CDC) prevention funding. The funding for these current efforts will not be assumed by near universal insurance coverage for a variety of reasons, including the need to care for populations who are neglected by health care reform, to continue services unlikely to be reimbursable, and to offer care in a range of locations other than licensed health care facilities.     

Consumer-driven health plans: early evidence and potential impact on hospitals

Consumer-driven health plans-tax--advantaged accounts paired with high-deductible coverage--represent a small but rapidly growing part of insurance offerings. Supporters believe that such plans will encourage consumers to become better-informed, more cost-conscious users of health care. Opponents worry that patients will obtain fewer necessary and nonessential services alike. Early evidence suggests that consumer-driven plans result in lower costs and increased use of preventive and chronic care services, but these findings are preliminary. The biggest effect for hospitals might be the pressure produced for increased price transparency and greater uniformity in pricing, although high-deductible plans also could reduce hospital spending by reducing use.     

Arsenic exposure and its impact on health in Chile

The problem of arsenic in Chile was reviewed. In Chile, the population is exposed to arsenic naturally via drinking-water and by air pollution resulted from mining activities. The sources of arsenic were identified to estimate the exposure of population to arsenic through air, water, and food. Health effects, particularly early effects, observed in children and adults, such as vascular diseases (premature cardiac infarct), respiratory illnesses (bronchiectasis), and skin lesions have been described. Chronic effects, such as lung and bladder cancers, were reported 20 years after peak exposure and persisted 27 years after mitigation measures for removing arsenic from drinking surface water were initiated. Although the effects of arsenic are similar in different ethnic and cultural groups (e.g. Japanese, Chinese, Indian, Bangladeshi, American, and Taiwanese), variations could be explained by age at exposure, the dose received, smoking, and nutrition. Since health effects were observed at arsenic levels of 50 microg/L in drinking-water, it is advised that Chile follows the World Health Organization's recommendation of 10 microg/L. The Chilean experience in removal of arsenic suggests that it is feasible to reach this level using the conventional coagulation process.     

The impact of exposure categorisation for grouped analyses of cohort data

Background: Poisson regression is routinely used in occupational and environmental epidemiology. For typical Poisson regression analyses, person-time and events are tabulated by categorising predictor variables that were originally measured on a continuous scale. In order to estimate a dose-response trend, a researcher must decide how to categorise exposures and how to assign scores to exposure groups. Aims: To investigate the impact on regression results of decisions about exposure categorisation and score assignment. Methods: Cohort data were generated by Monte Carlo simulation methods. Exposure categories were defined by quintiles or deciles of the exposure distribution. Scores were assigned to exposure groups based on category midpoint and mean exposure levels. Estimated exposure-disease trends derived via Poisson regression were compared to the "true" association specified for the simulation. Results: Under the assumption that exposures conform to a lognormal or exponential distribution, trend estimates tend to be negatively biased when scores are assigned based on category midpoints and positively biased when scores are assigned based on cell specific mean values. The degree of bias was greater when exposure categories were defined by quintiles of the exposure distribution than when categories were defined by deciles of the exposure distribution. Conclusions: The routine practice of exposure categorisation and score assignment introduces exposure misclassification that may be differential with respect to disease status and, consequently, lead to biased exposure-disease trend estimates. When using the Poisson regression method to evaluate exposure-disease trends, such problems can be minimised (but not necessarily eliminated) by forming relatively refined exposure categories based on percentiles of the exposure distribution among cases, and by assigning scores to exposure categories that reflect person-time weighted mean exposure levels.     

The health impact of environmental pollutants: a special focus on lead exposure in South Africa

Studies have shown blood lead levels of some children in South Africa at levels of health concern. New studies show even relatively low lead levels to have detrimental effects on cognitive function in young children. Large numbers of South African inner-city and other children have been shown to have unacceptably high blood lead levels. Studies indicate that blood lead levels of children living in South Africa's urban areas are higher than those of children in most developed countries, including Great Britain, Europe, and the United States. Although data and reported studies are very sparse, mean blood lead levels of approximately 15 microg/dl have been reported in children. Elevated blood lead levels were associated with socioeconomic status and housing conditions. Key environmental risk factors for elevated blood levels were contaminated soil and dust in the urban environment, and the still large number of automobiles using leaded gasoline. In view of emerging evidence linking lead at increasingly lower levels to adverse effects in children, the South African government is taking actions to reduce lead exposure among vulnerable groups. Currently, South Africa has no national lead surveillance program. The government, therefore, has developed international and regional partnerships to prevent and address the problem of lead exposure.     

The impact of antidepressant treatment on population health: synthesis of data from two national data sources in Canada

Background  

In randomized, controlled trials, antidepressant medications have been shown to reduce the duration of major depressive episodes and to reduce the frequency of relapse during long-term treatment. The epidemiological impact of antidepressant use on episode duration and relapse frequency, however, has not been described.     

妊娠期重金属暴露水平对母儿的影响及相关因素分析

目的 研究孕妇和脐血中血汞、砷的暴露水平及其对妊娠结局、妊娠并发症的影响,分析脐血中血汞、砷暴露水平的影响因素,用以指导孕产妇优生优育.方法 选取本院分娩的400例病例,采用微波消解和质谱分析方法测定孕妇和脐血中血砷含量,利用原子吸收法测定血汞含量.对孕妇居住环境、生活方式、膳食等情况等进行问卷调查,分析产妇血及胎儿脐血汞、砷暴露水平与妊娠结局的影响.结果 新生儿脐血汞、砷水平[（4.42±1.11）μg/L,（3.75±4.28）μg/L]与其母血汞、砷水平[（2.47±1.09）μg/L,（3.61±2.92）μg/L]呈正相关（r=0.88,0.91,P＜0.05）.血汞、砷升高组的妊娠不良结局发生率（36.78%,31.11%）和妊娠并发症发生率（36.77%,28.90%）分别高于血汞、砷正常组（11.50%,12.90%,14.68%,15.13%,χ2=7.07、9.94,P＜0.01）.多元线性回归结果显示食海鱼为汞暴露的危险因素（χ2=8.28,P＜0.01）,孕期摄入水果和开窗通风换气为预防汞暴露的保护性因素（χ2=9.02、6.05,P＜0.05）;使用化妆品和食用罐装食品为砷暴露的危险因素（χ2=7.35、10.38,P＜0.05）,孕妇高文化程度为预防砷暴露的保护性因素（χ2=8.87,P＜0.05）.结论 新生儿脐血汞、砷水平与母亲血汞、砷水平及环境因素、孕期保健等因素有关.加强健康教育和孕妇孕期保健是预防新生儿汞、砷中毒的有效途径.     

The potential impact of comparative effectiveness research on the health of minority populations

Minorities suffer more frequently and more severely from many diseases than do non-Hispanic whites, and they often receive lower-quality care, which leads to poorer health outcomes. Given the diversity of the US population, comparative effectiveness research should capture the health outcomes of racial and ethnic minority groups and investigate whether disparities reflect variations in care or different responses to treatment. We recommend a number of measures to ensure that this research addresses the needs of minorities, including greater attention to subgroup analysis. We also recommend the increased recruitment of minorities for clinical trials, and such measures as using community health workers to translate research results in ways that will increase their relevance to minority patients.     

The use of biomonitoring data in exposure and human health risk assessments

Biomonitoring uses analytic methods that permit the accurate measurement of low levels of environmental chemicals in human tissues. However, depending on the intended use, biomonitoring, like all exposure tools, may not be a stand-alone exposure assessment tool for some of its environmental public health uses. Although biomonitoring data demonstrate that many environmental chemicals are absorbed in human tissues, uncertainty exists regarding if and at what concentrations many of these chemicals cause adverse health outcomes. Moreover, without exposure pathway information, it is difficult to relate biomonitoring results to sources and routes of exposure and develop effective health risk management strategies. In September 2004, the Health and Environmental Sciences Institute, U.S. Environmental Protection Agency, Centers for Disease Control and Prevention, Agency for Toxic Substances and Disease Registry, and International Council of Chemical Associations co-sponsored the International Biomonitoring Workshop, which explored the processes and information needed for placing biomonitoring data into perspective for risk assessment purposes, with special emphasis on integrating biomarker measurements of exposure, internal dose, and potential health outcome. Scientists from international governments, academia, and industry recommended criteria for applying biomonitoring data for various uses. Six case studies, which are part of this mini-monograph, were examined: inorganic arsenic, methyl eugenol, organophosphorus pesticides, perfluorooctanesulfonate, phthalates, and polybrominated diphenyl ethers. Based on the workshop and follow-up discussions, this overview article summarizes lessons learned, identifies data gaps, outlines research needs, and offers guidance for designing and conducting biomonitoring studies, as well as interpreting biomonitoring data in the context of risk assessment and risk management.     

The effects of PCB exposure and fish consumption on endogenous hormones.

Previous studies have suggested that exposure to polychlorinated biphenyls (PCBs) may alter thyroid function, but data on effects of PCB exposure on other endogenous hormones has been lacking. The current study is ancillary to a larger investigation of the effects of Great Lakes fish consumption on PCBs and reproductive function. In the current study we examine associations of PCBs, 1,1-bis (4-chlorophenyl)-2,2-dichloroethene (DDE), and fish consumption with thyroid and steroid hormones in 178 men and PCBs, DDE, and fish consumption with thyroid hormones in 51 women from the original study. Serum PCB level and consumption of Great Lakes fish are associated with significantly lower levels of thyroxine (T(4)) and free thyroxine index (FTI) in women and with significantly lower levels of T(4) in men. Fish consumption, but not PCB level, is significantly and inversely associated with triiodothyronine (T(3)) in men. Results for thyroid-stimulating hormone (TSH) are inconsistent. Among men, there are significant inverse associations of both PCB and fish consumption with sex hormone-binding globulin (SHBG)-bound testosterone, but no association with SHBG or free testosterone. There are no significant overall associations of PCB, DDE, or fish consumption with estrone sulfate, follicle-stimulating hormone, luteinizing hormone, or dehydroepiandrosterone sulfate. The results of this study are consistent with previous studies showing effects of fish consumption and PCB exposure on thyroid hormones and suggest that PCBs may also decrease steroid binding to SHBG. Elucidation of specific mechanisms must await future investigations.     

某金矿综合回收伴生金属试验研究

近几年我国的黄金行业迅猛发展,包括金矿的开采。金矿的生产工艺一般包括凿岩、破碎、搬运、研磨、冶炼等过程,整个开采过程和尾矿矿渣的处理阶段均会释放多种重金属（如铜、铅、汞）。重金属具有长期性、隐蔽性和不可逆性的特点,不仅会对环境造成污染还会对矿址周围居民及矿工的健康形成威胁。机体铜过量与多种疾病如阿尔茨海默病和糖尿病之间有密不可分的关系,铅摄入过多则会导致DNA损伤及氧化损伤,严重则可致癌,汞在体内累积超标则会损害多个器官系统。了解金矿开采释放重金属的途径及重金属对人群产生的健康损伤,有助于金矿周边居民采取防护措施,保护健康。     

环境电磁场与人群超敏性

为了预防已知的电磁场对人体健康的不良影响,极低频(ELF)和射频(RF)频段的电磁场暴露限值已经制定且被广泛采用(ICNIRP 1998)[1].该导则的基本限值(basic limits)限定了电磁场的体内暴露剂量,例如ELF电场和(或)磁场在体内诱导的电流密度,以及RF电磁场(RF-EMF)在体内的比吸收率(SAR).     

Cross-national comparisons of health systems using OECD data, 1999

This paper presents selected components of the most recent (1999) Organization for Economic Cooperation and Development (OECD) Health Data. Previous trends in spending for health care, supply and use of health care resources, and health status are updated for the thirty industrialized countries in the OECD. In 1999 the United States spent 53 percent more on health care than any other OECD country spent. The paper reviews two possible reasons for the difference: economic development and population aging. It discusses spending, supply, and utilization for specific categories of health care services: pharmaceuticals, physicians, hospitals, and high-technology services. The paper concludes with a consideration of the strengths and weaknesses of using OECD data to compare health systems.