Suchergebnisse

Abstract
We have studied rates of diabetes in 601 members of the Mohawk Nation at Akwesasne, ages 18–84 years, in relation to serum concentrations of 101 polychlorinated biphenyl (PCB) congeners and three chlorinated pesticides [dichlorodiphenyldichloroethylene (DDE), hexachlorobenzene (HCB) and mirex]. Diabetes was determined from either a diagnosis by a physician or by having a fasting glucose concentration of >125 mg/dL. Rates of diabetes are high in this community. Three models were used. In the first model rate ratios (RR) were determined for quartiles of total PCBs after adjustment for age, sex, body mass index (BMI) and total serum lipids. For total PCBs RR=2.21 (1.2–4.2), while for total pesticides RR=3.75 (1.3–10.7). When the total PCB results were also adjusted for total pesticides and the total pesticide results were also adjusted for total PCBs (Model 2) the RRs were somewhat reduced. In Model 3 we considered subgroups of PCBs based on numbers of chlorines on the molecule (tri-/tetra, penta-/hexa, hepta plus) and numbers of ortho chlorines (non-/mono; di-, tri-/tetra-), and considered each of the pesticides individually after adjustment for all other contaminants as well as age, sex, BMI and serum lipids. We found a highly significant association between diabetes and PCBs with only three or four chlorines (RR=5.02), but no significant association with those with greater chlorination. When evaluating PCBs based on numbers of ortho chlorines only, those with no or one ortho chlorine showed significant associations. As mono-ortho PCBs include some with dioxin-like activity, we compared those with and without a TEF, and found that the association with diabetes was exclusively with the non-dioxin-like congeners. Of the pesticides only hexachlorobenzene showed a small but significant association with diabetes. Because lower chlorinated PCBs are more volatile and do not greatly accumulate in fish, these results suggest that inhalation is the major route of exposure to those PCBs that increase risk of diabetes.

Abstract
Lead poisoning is a serious environmental health problem in every country in the world. Exposure to lead results in neurocognitive and behavioral changes, has adverse effects on the immune system, causes anemia, hypertension and perturbs other organ systems. The effects of lead poisoning are most critical for children because their bodies are growing and developing, and particularly because agents that reduce cognitive function and attention span as well as promote disruptive behavior will have life-long consequences. Lead exposure, especially to children, is a major health disparity issue. If the next generation starts with reduced cognitive ability, there will be significant barriers for development of skills and country-wide development. While there are many sources of exposure to lead, the commonest source is lead in soil and dust. Since lead is an element, it does not go away and past releases of lead into the environment remain as soil and dust contamination. This is an especially important route of exposure to children because children regularly play in soil and are exposed via hand-to-mouth activity. In addition to indoor sources of lead, contaminated soil is tracked on shoes or feet and blown by air currents into homes, accumulating in household dust which is a major source of exposure for both children and adults. The purpose of this review is to determine standards presumed to be health protective for lead and dust in different countries. We find that many countries have no standards for lead in soil and dust and rely on standards set by the World Health Organization or the US Environmental Protection Agency, and these standards may or may not be enforced. There is considerable variation in standards set by other countries.

Abstract
In 2013, 60 scientists, representing a larger group of 174 scientists from 26 nations, met in Halifax, Nova Scotia to consider whether – using published research – it was logical to anticipate that a mixture of chemicals, each thought to be non-carcinogenic, might act together in that mixture as a virtual carcinogen. The group identified 89 such chemicals, each one affecting one or more Hallmark(s) – collectively covering all Hallmarks of Cancer – confirming the possibility that a chemical mixture could induce all the Hallmarks and function as a virtual carcinogen, thereby supporting the concern that chemical safety research that does not evaluate mixtures, is incomplete. Based on these observations, the Halifax Project developed the Low-Dose Carcinogenesis Hypothesis which posits "…that low-dose exposures to [mixtures of] disruptive chemicals that are not individually carcinogenic may be capable of instigating and/or enabling carcinogenesis." Although testing all possible combinations of over 80,000 chemicals of commerce would be impractical, prudence requires designing a methodology to test whether low-dose chemical mixtures might be carcinogenic. As an initial step toward testing this hypothesis, we conducted a mini review of published empirical observations of biological exposures to chemical mixtures to assess what empirical data exists on which to base future research. We reviewed studies on chemical mixtures with the criteria that the studies reported both different concentrations of chemicals and mixtures composed of different chemicals. We found a paucity of research on this important question. The majority of studies reported hormone related processes and used chemical concentrations selected to facilitate studying how mixtures behave in experiments that were often removed from clinical relevance, i.e., chemicals were not studied at human-relevant concentrations. New research programs must be envisioned to enable study of how mixtures of small doses of chemicals affect human health, starting, when at all possible, from non-malignant specimens when studies are done in vitro. This research should use human relevant concentrations of chemicals, expand research beyond the historic focus on endocrine endpoints and endocrine related cancers, and specifically seek effects that arise uniquely from exposure to chemical mixtures at human-relevant concentrations.

Abstract
The roles of many environmental contaminants in increasing breast cancer risk remain controversial. Arsenic (As) is a major global environmental contaminant and carcinogen. We conducted a systematic review of the role of As and gene-arsenic interactions in susceptibility to breast cancer. Following a systematic literature search using well-defined inclusion/exclusion criteria, a total of 15 epidemiologic studies (two meta-analyses, three systematic reviews, three cohort studies, two case-control studies, and five cross-sectional studies) were reviewed. In addition, several animal, in vitro, in vivo, and in silico (i.e., computer modeling) studies provided mechanistic insights into the association between As and breast cancer. Our review suggests a possible overall main effect of As on breast cancer risk. The evidence for an effect of gene-As interactions on breast cancer risk is strong. Studies that measured levels of As metabolites among participants and/or evaluated interactions between As exposure and genetic or epigenetic factors generally reported positive associations with breast cancer risk. Our analysis of the Comparative Toxicogenomics and the Ingenuity Pathway Analysis Databases provided further evidence for As-gene interactions and their effects on breast cancer-related biologic pathways. Our findings provide potential leads for future epidemiologic studies of As-associated cancer risks and interventions to reduce population exposure.

AbstractOverweight and obesity are now a global epidemic, with more than one in five people qualifying as obese worldwide. These conditions are accompanied by excessive rates of non-communicable diseases (NCDs) related to overweight, like type 2 diabetes mellitus, hypertension, and cardiovascular diseases. Saudi Arabia, which has become increasingly westernized over the past few decades now has one of the highest prevalence rates of overweight and obesity, even in children. This puts the population at great risk for increased rates of NCD mortality. Competing cultures is partly to blame, as the combination of persisting traditional Saudi cultural practices, modern cultural changes, and economic prosperity has created an obesogenic environment that promotes unhealthy eating, sedentary lifestyles, and weight gain. Overweight and obesity are more prevalent in Saudi women than in Saudi men. Interventions targeting the environment are needed in order to promote greater health through healthy eating decisions and increased physical activity or exercise (especially for women).

AbstractProviding sources of sustainable and quality potable water in Uganda is a significant public health issue. This project aimed at identifying and prioritizing possible actions on how sustainable high quality potable water in Uganda's water supply systems could be achieved. In that respect, a review of both the current water supply systems and government programs on drinking water in Uganda was completed. Aspects of quantity, quality, treatment methods, infrastructure, storage and distribution of water for different water systems were evaluated and compared with the existing water supply systems in the U.S., Latin America and the Caribbean, for purposes of generating feasible recommendations and opportunities for improvement. Uganda utilizes surface water, groundwater, and rainwater sources for consumption. Surface water covers 15.4% of the land area and serves both urban and rural populations. Lake Victoria contributes about 85% of the total fresh surface water. Potable water quality is negatively affected by the following factors: disposal of sewage and industrial effluents, agricultural pesticides and fertilizers, and surface run-offs during heavy rains. The total renewable groundwater resources in Uganda are estimated to be 29 million m