Special Issue "Advances in Epidemiology"
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A special issue of International Journal of Environmental Research and Public Health (ISSN 1660-4601).
Deadline for manuscript submissions: closed (31 December 2009)
Special Issue Editor
Guest Editor
Dr. Scott A. Venners
Simon Fraser University, Faculty of Health Sciences, 8888 University Drive, Burnaby, BC, V5A 1S6, Canada
Website: http://www.fhs.sfu.ca/portal_memberdata/svenners
E-Mail: scott_venners@sfu.ca
Phone: +1 778 782 8494
Fax: +1 778 782 5927
Interests: molecular environmental epidemiology; biomarkers; gene-environment interactions; fertility; pregnancy outcome
Special Issue Information
Dear Colleagues,
Advances in epidemiology can occur when interdisciplinary knowledge is applied to research design, implementation or interpretation. The goal of this special issue is to highlight novel theoretical, methodological or technological advances in epidemiological research on human exposures to anthropogenic factors and public or occupational health. Empirical papers on research using emerging or novel theories, methods or technologies are encouraged as are review papers that point to new directions of research with broad applicability and relevance for public and occupational health.
Dr. Scott A. Venners
Guest Editor
Submission
The Int. J. Environ. Res. Public Health (ISSN 1660-4601) was launched in 2004 and is an Open Access journal, with the main Editorial Office located in Basel, Switzerland. It has been accepted for coverage in Science Citation Index Expanded, available as the Web of Science and in Current Contents/Agriculture, Biology, and Environmental Sciences. Coverage will begin with the 2009 issues. This journal is also abstracted and indexed very rapidly by Chemical Abstracts, MedLine/PubMed and EMBASE. The IJERPH maintains a rapid editorial procedure and a rigorous peer-review system. Well written papers have been peer-reviewed and published in less than 4 weeks from manuscript submission. All papers published in IJERPH have DOI numbers.
All papers should be submitted to ijerph@mdpi.com with copy to the guest editor. To be published continuously until the deadline and papers will be listed together at this special issue website.
Please visit the Instructions for Authors page before submitting a paper. Open Access publication fees are 300 CHF per paper. English correction fees (250 CHF) will be added in certain cases (550 CHF per paper for those papers that require extensive additional formatting and/or English corrections.).
Keywords
- human exposure to anthropogenic factors
- novel theories, methods or technologies in epidemiological research
- public health
- occupational health
Published Papers (31 papers)
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Received: 29 July 2008 / Accepted: 2 September 2009 / Published: 3 September 2009
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Abstract: This paper aims to present life years at risk (LYAR), a new measure of population health needs for primary, secondary and tertiary prevention, which classifies health outcomes by care type and distinguishes between positive and negative outcomes. It is determined by the probability of ill-health event, population size and life years lost, based on expected incidence, prevalence and mortality. The LYAR consists of two components: the observed LYAR, available using disability adjusted life years, and the avoided LYAR. Three examples are given to illustrate the calculation and application of the measure. The advantages, disadvantages and policy implications are also discussed.
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Received: 16 July 2009 / Accepted: 8 September 2009 / Published: 11 September 2009
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Abstract: Abstract: In a follow-up study of mortality among North American synthetic rubber industry workers, cumulative exposure to 1,3-butadiene was positively associated with leukemia. Problems with historical exposure estimation, however, may have distorted the association. To evaluate the impact of potential inaccuracies in exposure estimation, we conducted uncertainty analyses of the relation between cumulative exposure to butadiene and leukemia. We created the 1,000 sets of butadiene estimates using job-exposure matrices consisting of exposure values that corresponded to randomly selected percentiles of the approximate probability distribution of plant-, work area/job group-, and year specific butadiene ppm. We then analyzed the relation between cumulative exposure to butadiene and leukemia for each of the 1,000 sets of butadiene estimates. In the uncertainty analysis, the point estimate of the RR for the first non zero exposure category (>0–<37.5 ppm-years) was most likely to be about 1.5. The rate ratio for the second exposure category (37.5–<184.7 ppm-years) was most likely to range from 1.5 to 1.8. The RR for category 3 of exposure (184.7–<425.0 ppm-years) was most likely between 2.1 and 3.0. The RR for the highest exposure category (425.0+ ppm-years) was likely to be between 2.9 and 3.7. This range off RR point estimates can best be interpreted as a probability distribution that describes our uncertainty in RR point estimates due to uncertainty in exposure estimation. After considering the complete probability distributions of butadiene exposure estimates, the exposure-response association of butadiene and leukemia was maintained. This exercise was a unique example of how uncertainty analyses can be used to investigate and support an observed measure of effect when occupational exposure estimates are employed in the absence of direct exposure measurements.
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Received: 2 September 2009 / Accepted: 28 September 2009 / Published: 2 October 2009
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Abstract: Vitamin D and calcium insufficiencies are risk factors for multiple chronic diseases. Data from 46 recent studies from Europe, North America, South-East Asia and the South Pacific area clearly indicate that a low vitamin D status and inadequate calcium nutrition are highly prevalent in the general population (30–80%), affecting both genders. The extent of insufficiencies is particularly high in older populations, and in some geographical areas, also in children and in young women of child-bearing age, in ethnic minorities and immigrants, as well as in people of low socio-economic status. Enrichment of cereal grain products with vitamin D and calcium would be a viable approach to increase consumption and improve health outcomes in the general population worldwide.
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Received: 18 August 2009 / Accepted: 9 October 2009 / Published: 16 October 2009
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Abstract: This study aimed at establishing the relationship between annoyance scores and modelled air pollution in “Chemical Valley”, Sarnia, Ontario (Canada). Annoyance scores were taken from a community health survey (N = 774); and respondents’ exposure to nitrogen dioxide (NO2) and sulphur dioxide (SO2) were estimated using land use regression (LUR) models. The associations were examined by univariate analysis while multivariate logistic regression was used to examine the determinants of odour annoyance. The results showed that odour annoyance was significantly correlated to modelled pollutants at the individual (NO2, r = 0.15; SO2, r = 0.13) and census tract (NO2, r = 0.56; SO2, r = 0.67) levels. The exposure-response relationships show that residents of Sarnia react to very low pollution concentrations levels even if they are within the Ontario ambient air quality criteria. The study found that exposure to high NO2 and SO2 concentrations, gender, and perception of health effects were significant determinants of individual odour annoyance reporting. The observed association between odour annoyance and modelled ambient pollution suggest that individual and census tract level annoyance scores may serve as proxies for air quality in exposed communities because they capture the within area spatial variability of pollution. However, questionnaire-based odour annoyance scores need to be validated longitudinally and across different scales if they are to be adopted for use at the national level.
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Received: 30 September 2009 / Accepted: 25 November 2009 / Published: 30 November 2009
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Abstract: Prediction of high-risk individuals and the multi-risk approach are common inquiries in caries risk epidemiology. These studies prepared the ground for future studies; specific hypotheses about causal patterns can now be formulated and tested applying advanced statistical methods designed for causal studies, such as structural equation modeling, path analysis and multilevel modeling. Causal studies should employ measurements, analyses and interpretation of findings, which are in accordance to causal aims. Examples of causal empirical studies from medical and oral research are presented.
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Received: 13 October 2008 / Accepted: 25 November 2009 / Published: 7 December 2009
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Abstract: Following contamination from the Chernobyl accident in April 1986 excess infant leukemia (0–1 y) was reported from five different countries, Scotland, Greece, Germany, Belarus and Wales and Scotland combined. The cumulative absorbed doses to the fetus, as conventionally assessed, varied from 0.02 mSv in the UK through 0.06 mSv in Germany, 0.2 mSv in Greece and 2 mSv in Belarus, where it was highest. Nevertheless, the effect was real and given the specificity of the cohort raised questions about the safety of applying the current radiation risk model of the International Commission on Radiological Protection (ICRP) to these internal exposures, a matter which was discussed in 2000 by Busby and Cato [7,8] and also in the reports of the UK Committee examining Radiation Risk from Internal Emitters. Data on infant leukemia in the United Kingdom, chosen on the basis of the cohorts defined by the study of Greece were supplied by the UK Childhood Cancer Research Group. This has enabled a study of leukemia in the combined infant population of 15,466,845 born in the UK, Greece, and Germany between 1980 and 1990. Results show a statistically significant excess risk RR = 1.43 (95% CI 1.13 < RR < 1.80 (2-tailed); p = 0.0025) in those born during the defined peak exposure period of 01/07/86 to 31/12/87 compared with those born between 01/01/80 and 31/12/85 and 01/01/88 and 31/12/90. The excess risks in individual countries do not increase monotonically with the conventionally calculated doses, the relation being biphasic, increasing sharply at low doses and falling at high doses. This result is discussed in relation to fetal/cell death at higher doses and also to induction of DNA repair. Since the cohort is chosen specifically on the basis of exposure to internal radionuclides, the result can be expressed as evidence for a significant error in the conventional modeling for such internal fetal exposures.
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Received: 6 November 2009 / Accepted: 3 December 2009 / Published: 7 December 2009
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Abstract: Based on the 40-year follow-up of the Framingham Heart Study (FHS), we used logistic regression models to demonstrate that different designs of an observational study may lead to different results about the association between BMI and all-cause mortality. We also used dynamic survival models to capture the time-varying relationships between BMI and mortality in FHS. The results consistently show that the association between BMI and mortality is dynamic, especially for men. Our analysis suggests that the dynamic property may explain part of the heterogeneity observed in the literature about the association of BMI and mortality.
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Received: 29 October 2009 / Accepted: 24 December 2009 / Published: 31 December 2009
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Abstract: Epidemiological studies often produce false positive results due to use of statistical approaches that either ignore or distort time. The three time-related issues of focus in this discussion are: (1) cross-sectional vs. cohort studies, (2) statistical significance vs. public health significance, and (3), how risk factors "work together" to impact public health significance. The issue of time should be central to all thinking in epidemiology research, affecting sampling, measurement, design, analysis and, perhaps most important, the interpretation of results that might influence clinical and public-health decision-making and subsequent clinical research.
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Received: 1 December 2009 / Accepted: 11 January 2010 / Published: 13 January 2010
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Abstract: Beryllium is a lightweight metal with unique qualities related to stiffness, corrosion resistance, and conductivity. While there are many useful applications, researchers in the 1930s and l940s linked beryllium exposure to a progressive occupational lung disease. Acute beryllium disease is a pulmonary irritant response to high exposure levels, whereas chronic beryllium disease (CBD) typically results from a hypersensitivity response to lower exposure levels. A blood test, the beryllium lymphocyte proliferation test (BeLPT), was an important advance in identifying individuals who are sensitized to beryllium (BeS) and thus at risk for developing CBD. While there is no true "gold standard" for BeS, basic epidemiologic concepts have been used to advance our understanding of the different screening algorithms.
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Received: 27 November 2009 / Accepted: 11 January 2010 / Published: 19 January 2010
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Abstract: With research suggesting increasing incidence of pediatric neurodevelopmental disorders, questions regarding etiology continue to be raised. Neurodevelopmental function tests have been used in epidemiology studies to evaluate relationships between environmental chemical exposures and neurodevelopmental deficits. Limitations of currently used tests and difficulties with their interpretation have been described, but a comprehensive critical examination of tests commonly used in studies of environmental chemicals and pediatric neurodevelopmental disorders has not been conducted. We provide here a listing and critical evaluation of commonly used neurodevelopmental tests in studies exploring effects from chemical exposures and recommend measures that are not often used, but should be considered. We also discuss important considerations in selecting appropriate tests and provide a case study by reviewing the literature on polychlorinated biphenyls.
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Received: 24 December 2009 / Accepted: 18 January 2010 / Published: 21 January 2010
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Abstract: The basic reproduction number, R0, a summary measure of the transmission potential of an infectious disease, is estimated from early epidemic growth rate, but a likelihood-based method for the estimation has yet to be developed. The present study corrects the concept of the actual reproduction number, offering a simple framework for estimating R0 without assuming exponential growth of cases. The proposed method is applied to the HIV epidemic in European countries, yielding R0 values ranging from 3.60 to 3.74, consistent with those based on the Euler-Lotka equation. The method also permits calculating the expected value of R0 using a spreadsheet.
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Received: 8 December 2009 / Accepted: 22 January 2010 / Published: 26 January 2010
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Abstract: This study aimed to analyze the possible resemblance or difference in outcome in a case-control study of quality of life for IBS patients compared to controls free from the disease, when a matching procedure for age and sex was applied for the control group compared to when all participating subjects were included in the control group. The main result was that almost the same and identical results were found irrespective of whether matching or not matching was applied in this epidemiological case-control study. The matching procedure however, slightly diminished the statistical power of the results.
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Received: 16 November 2009 / Accepted: 21 January 2010 / Published: 27 January 2010
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Abstract: Multilevel models are overwhelmingly applied to single health outcomes, but when two or more health conditions are closely related, it is important that contextual variation in their joint prevalence (e.g., variations over different geographic settings) is considered. A multinomial multilevel logit regression approach for analysing joint prevalence is proposed here that includes subject level risk factors (e.g., age, race, education) while also taking account of geographic context. Data from a US population health survey (the 2007 Behavioral Risk Factor Surveillance System or BRFSS) are used to illustrate the method, with a six category multinomial outcome defined by diabetic status and weight category (obese, overweight, normal). The influence of geographic context is partly represented by known geographic variables (e.g., county poverty), and partly by a model for latent area influences. In particular, a shared latent variable (common factor) approach is proposed to measure the impact of unobserved area influences on joint weight and diabetes status, with the latent variable being spatially structured to reflect geographic clustering in risk.
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Received: 29 December 2009 / Accepted: 27 December 2010 / Published: 28 January 2010
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Abstract: This paper aims to provide direct and indirect evidence on setting up rules for applications of the empirical Bayes shrinkage (EBS), and offers cautionary remarks concerning its applicability. In epidemiology, there is still a lack of relevant criteria in the application of EBS. The bias of the shrinkage estimator is investigated in terms of the sums of errors, squared errors and absolute errors, for both total and individual groups. The study reveals that assessing the underlying exchangeability assumption is important for appropriate use of EBS. The performance of EBS is indicated by a ratio statistic f of the between-group and within-group mean variances. If there are significant differences between the sample means, EBS is likely to produce erratic and even misleading information.
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Received: 31 December 2009 / Accepted: 1 February 2010 / Published: 3 February 2010
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Abstract: Recently, a population-based case-control study observed a 60% increased odds ratio (OR) for cutaneous squamous cell carcinoma (SCC) among women who had ever used oral contraceptives (OCs) compared with non users (95% confidence interval (CI) = 1.0–2.5). To further characterize the putative association between OC use and SCC risk, we conducted a nested case-control study using a large retrospective cohort of 111,521 Kaiser Permanente Northern California members. Multivariable conditional logistic regression was used to estimate ORs and CIs adjusting for known and hypothesized SCC risk factors. Pre-diagnostic OC use was associated with a statistically significant increased OR for SCC in univariate analysis (OR = 2.4, CI = 1.2–4.8), with borderline statistical significance in multivariable analysis (CI = 2.0, CI = 0.91–4.5). Given the high incidence of SCC in the general population and the prevalent use of OCs among women in the United States, there is a need for more large, carefully designed epidemiologic studies to determine whether the observed association between OC use and SCC can be replicated and to better understand the etiologic basis of an association if one exists.
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Received: 15 December 2009 / Accepted: 16 February 2010 / Published: 22 February 2010
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Abstract: Human papillomavirus (HPV) is often transmitted through sexual partnerships. However, many previous HPV transmission models ignore the existence of partnerships by implicitly assuming that each new sexual contact is made with a different person. Here, we develop a simplified pair model—based on the example of HPV—that explicitly includes sexual partnership formation and dissolution. We show that not including partnerships can potentially result in biased projections of HPV prevalence. However, if transmission rates are calibrated to match empirical pre-vaccine HPV prevalence, the projected prevalence under a vaccination program does not vary significantly, regardless of whether partnerships are included.
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Received: 31 December 2009 / Accepted: 16 February 2010 / Published: 23 February 2010
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Abstract: Within Canadian Aboriginal communities, the process for utilizing environmental health research evidence in the development of policies and programs is not well understood. This fundamental qualitative descriptive study explored the perceptions of 28 environmental health researchers, senior external decision-makers and decision-makers working within Aboriginal communities about factors influencing knowledge transfer and exchange, beliefs about research evidence and Traditional Knowledge and the preferred communication channels for disseminating and receiving evidence. The results indicate that collaborative relationships between researchers and decision-makers, initiated early and maintained throughout a research project, promote both the efficient conduct of a study and increase the likelihood of knowledge transfer and exchange. Participants identified that empirical research findings and Traditional Knowledge are different and distinct types of evidence that should be equally valued and used where possible to provide a holistic understanding of environmental issues and support decisions in Aboriginal communities. To facilitate the dissemination of research findings within Aboriginal communities, participants described the elements required for successfully crafting key messages, locating and using credible messengers to deliver the messages, strategies for using cultural brokers and identifying the communication channels commonly used to disseminate and receive this type of information.
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Received: 30 December 2009 / Accepted: 16 February 2010 / Published: 24 February 2010
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Abstract: The epidemiological transition model describes the changing relationship between humans and their diseases. The first transition occurred with the shift to agriculture about 10,000 YBP, resulting in a pattern of infectious and nutritional diseases still evident today. In the last two centuries, some populations have undergone a second transition, characterized by a decline in infectious disease and rise in degenerative disease. We are now in the throes of a third epidemiological transition, in which a resurgence of familiar infections is accompanied by an array of novel diseases, all of which have the potential to spread rapidly due to globalization.
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Received: 29 December 2009 / Accepted: 16 February 2010 / Published: 26 February 2010
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Abstract: Mendelian randomization refers to the random allocation of alleles at the time of gamete formation. In observational epidemiology, this refers to the use of genetic variants to estimate a causal effect between a modifiable risk factor and an outcome of interest. In this review, we recall the principles of a “Mendelian randomization” approach in observational epidemiology, which is based on the technique of instrumental variables; we provide simulations and an example based on real data to demonstrate its implications; we present the results of a systematic search on original articles having used this approach; and we discuss some limitations of this approach in view of what has been found so far.
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Received: 9 December 2009; in revised form: 3 February 2010 / Accepted: 16 February 2010 / Published: 5 March 2010
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Abstract: Leishmaniasis is a protozoan disease caused by the genus Leishmania transmitted by female phlebotomine sand flies. Surveillance of the prevalence of Leishmania and responsive vector species in endemic and surrounding areas is important for predicting the risk and expansion of the disease. Molecular biological methods are now widely applied to epidemiological studies of infectious diseases including leishmaniasis. These techniques are used to detect natural infections of sand fly vectors with Leishmania protozoa and are becoming powerful tools due to their sensitivity and specificity. Recently, genetic analyses have been performed on sand fly species and genotyping using PCR-RFLP has been applied to the sand fly taxonomy. In addition, a molecular mass screening method has been established that enables both sand fly species and natural leishmanial infections to be identified simultaneously in hundreds of sand flies with limited effort. This paper reviews recent advances in the study of sand flies, vectors of leishmaniasis, using molecular biological approaches.
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Received: 22 December 2009; in revised form: 14 January 2010 / Accepted: 22 February 2010 / Published: 10 March 2010
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Abstract: Recent studies demonstrate distinct changes in gene expression in cells exposed to a weak magnetic field (MF). Mechanisms of this phenomenon are not understood yet. We propose that proteins of the Cryptochrome family (CRY) are "epigenetic sensors" of the MF fluctuations, i.e., magnetic field-sensitive part of the epigenetic controlling mechanism. It was shown that CRY represses activity of the major circadian transcriptional complex CLOCK/BMAL1. At the same time, function of CRY, is apparently highly responsive to weak MF because of radical pairs that periodically arise in the functionally active site of CRY and mediate the radical pair mechanism of magnetoreception. It is known that the circadian complex influences function of every organ and tissue, including modulation of both NF-κB- and glucocorticoids- dependent signaling pathways. Thus, MFs and solar cycles-dependent geomagnetic field fluctuations are capable of altering expression of genes related to function of NF-κB, hormones and other biological regulators. Notably, NF-κB, along with its significant role in immune response, also participates in differential regulation of influenza virus RNA synthesis. Presented data suggests that in the case of global application (example—geomagnetic field), MF-mediated regulation may have epidemiological and other consequences.
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Received: 5 January 2009; in revised form: 20 February 2010 / Accepted: 8 March 2010 / Published: 11 March 2010
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Abstract: Intentional and unintentional injury is the leading cause of death and potential years of life lost in the first four decades of life in industrialized countries around the world. Despite surgical innovations and improved access to emergency care, research has shown that certain populations remain particularly vulnerable to the risks and consequences of injury. Recent evidence has shown that the analytical, data linkage, and mapping tools of geographic information systems (GIS) technology provide can further address these determinants and identify populations in need. This paper traces the history of injury prevention and discusses current and future challenges in furthering our understanding of the determinants of injury through the use of GIS.
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Received: 16 December 2009; in revised form: 28 January 2010 / Accepted: 8 March 2010 / Published: 11 March 2010
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Abstract: Decomposing stature into its major components is proving to be a useful strategy to assess the antecedents of disease, morbidity and death in adulthood. Human leg length (femur + tibia), sitting height (trunk length + head length) and their proportions, for example, (leg length/stature), or the sitting height ratio (sitting height/stature × 100), among others) are associated with epidemiological risk for overweight (fatness), coronary heart disease, diabetes, liver dysfunction and certain cancers. There is also wide support for the use of relative leg length as an indicator of the quality of the environment for growth during infancy, childhood and the juvenile years of development. Human beings follow a cephalo-caudal gradient of growth, the pattern of growth common to all mammals. A special feature of the human pattern is that between birth and puberty the legs grow relatively faster than other post-cranial body segments. For groups of children and youth, short stature due to relatively short legs (i.e., a high sitting height ratio) is generally a marker of an adverse environment. The development of human body proportions is the product of environmental x genomic interactions, although few if any specific genes are known. The HOXd and the short stature homeobox-containing gene (SHOX) are genomic regions that may be relevant to human body proportions. For example, one of the SHOX related disorders is Turner syndrome. However, research with non-pathological populations indicates that the environment is a more powerful force influencing leg length and body proportions than genes. Leg length and proportion are important in the perception of human beauty, which is often considered a sign of health and fertility.
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Cecilia Ximénez, Rene Cerritos, Liliana Rojas, Silvio Dolabella, Patricia Morán, Mineko Shibayama, Enrique González, Alicia Valadez, Eric Hernández, Olivia Valenzuela, Angélica Limón, Oswaldo Partida and Edwards F. Silva
Received: 19 December 2009; in revised form: 2 February 2010 / Accepted: 8 March 2010 / Published: 16 March 2010
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Abstract: For over 30 years it has been established that the Entamoeba histolytica protozoan included two biologically and genetically different species, one with a pathogenic phenotype called E. histolytica and the other with a non-pathogenic phenotype called Entamoeba dispar. Both of these amoebae species can infect humans. E. histolytica has been considered as a potential pathogen that can cause serious damage to the large intestine (colitis, dysentery) and other extraintestinal organs, mainly the liver (amebic liver abscess), whereas E. dispar is a species that interacts with humans in a commensal relationship, causing no symptoms or any tissue damage. This paradigm, however, should be reconsidered or re-evaluated. In the present work, we report the detection and genotyping of E. dispar sequences of DNA obtained from patients with amebic liver abscesses, including the genotyping of an isolate obtained from a Brazilian patient with a clinical diagnosis of intestinal amebiasis that was previously characterized as an E. dispar species. The genetic diversity and phylogenetic analysis performed by our group has shown the existence of several different genotypes of E. dispar that can be associated to, or be potentiality responsible for intestinal or liver tissue damage, similar to that observed with E. histolytica.
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Vincent Seaman, Steve M. Dearwent, Debra Gable, Brian Lewis, Susan Metcalf, Ken Orloff, Bruce Tierney, Jane Zhu, James Logue, David Marchetto, Stephen Ostroff, Ronald Hoffman, Mingjiang Xu, David Carey, Porat Erlich, Glenn Gerhard, Paul Roda, Joseph Iannuzzo, Robert Lewis, John Mellow, Linda Mulvihill, Zachary Myles, Manxia Wu, Arthur Frank, Carol Ann Gross-Davis, Judith Klotz, Adam Lynch, Joel Weissfeld, Rona Weinberg and Henry Cole
Received: 29 January 2010; in revised form: 13 March 2010 / Accepted: 16 March 2010 / Published: 17 March 2010
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Abstract: Cancer cluster investigations rarely receive significant public health resource allocations due to numerous inherent challenges and the limited success of past efforts. In 2008, a cluster of polycythemia vera, a rare blood cancer with unknown etiology, was identified in northeast Pennsylvania. A multidisciplinary group of federal and state agencies, academic institutions, and local healthcare providers subsequently developed a multifaceted research portfolio designed to better understand the cause of the cluster. This research agenda represents a unique and important opportunity to demonstrate that cancer cluster investigations can produce desirable public health and scientific outcomes when necessary resources are available.
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Received: 31 December 2009 / Accepted: 16 March 2010 / Published: 18 March 2010
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Abstract: Applied research in a public health setting seeks to provide professionals with insights and knowledge into complex environmental issues to guide actions that reduce inequalities and improve health. We describe ten environmental case studies that explore the public perception of health risk. We employed logical analysis of components of each case study and comparative information to generate new evidence. The findings highlight how concerns about environmental issues measurably affect people’s wellbeing and led to the development of new understanding about the benefits of taking an earlier and more inclusive approach to risk communication that can now be tested further.
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Received: 11 January 2010; in revised form: 1 March 2010 / Accepted: 16 March 2010 / Published: 19 March 2010
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Abstract: Branching processes are stochastic individual-based processes leading consequently to a bottom-up approach. In addition, since the state variables are random integer variables (representing population sizes), the extinction occurs at random finite time on the extinction set, thus leading to fine and realistic predictions. Starting from the simplest and well-known single-type Bienaymé-Galton-Watson branching process that was used by several authors for approximating the beginning of an epidemic, we then present a general branching model with age and population dependent individual transitions. However contrary to the classical Bienaymé-Galton-Watson or asymptotically Bienaymé-Galton-Watson setting, where the asymptotic behavior of the process, as time tends to infinity, is well understood, the asymptotic behavior of this general process is a new question. Here we give some solutions for dealing with this problem depending on whether the initial population size is large or small, and whether the disease is rare or non-rare when the initial population size is large.
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Received: 10 February 2010; in revised form: 3 March 2010 / Accepted: 16 March 2010 / Published: 19 March 2010
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Abstract: Over evolutionary time humans have developed a complex biological relationship with soils. Here we describe modes of soil exposure and their biological implications. We consider two types of soil exposure, the first being the continuous exposure to airborne soil, and the second being dietary ingestion of soils, or geophagy. It may be assumed that airborne dust and ingestion of soil have influenced the evolution of particular DNA sequences which control biological systems that enable individual organisms to take advantage of, adapt to and/or protect against exposures to soil materials. We review the potential for soil exposure as an environmental source of epigenetic signals which may influence the function of our genome in determining health and disease.
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Received: 31 December 2009; in revised form: 20 February 2010 / Accepted: 16 March 2010 / Published: 26 March 2010
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Abstract: This paper has two aims: (1) to summarize various geographic information science methods; and (2) to provide a review of studies that have employed such methods. Though not meant to be a comprehensive review, this paper explains when certain methods are useful in epidemiological studies and also serves as an overview of the growing field of spatial epidemiology.
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Received: 12 February 2010; in revised form: 26 March 2010 / Accepted: 29 March 2010 / Published: 1 April 2010
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Abstract: Typical statistical analysis of epidemiologic data captures uncertainty due to random sampling variation, but ignores more systematic sources of variation such as selection bias, measurement error, and unobserved confounding. Such sources are often only mentioned via qualitative caveats, perhaps under the heading of ‘study limitations.’ Recently, however, there has been considerable interest and advancement in probabilistic methodologies for more integrated statistical analysis. Such techniques hold the promise of replacing a confidence interval reflecting only random sampling variation with an interval reflecting all, or at least more, sources of uncertainty. We survey and appraise the recent literature in this area, giving some prominence to the use of Bayesian statistical methodology.
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Received: 1 March 2010; in revised form: 14 April 2010 / Accepted: 14 April 2010 / Published: 19 April 2010
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Abstract: Heart failure has been singled out as an emerging epidemic, which could be the result of increased incidence and/or increased survival leading to increased prevalence. Knowledge of the responsibility of each factor in the genesis of the epidemic is crucial for prevention. Population-based studies have shown that, over time, the incidence of heart failure remained overall stable, while survival improved. Therefore, the heart failure epidemic is chiefly one of hospitalizations. Data on temporal trends in the incidence and prevalence of heart failure according to ejection fraction and how it may have changed over time are needed while interventions should focus on reducing the burden of hospitalizations in hear failure.
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Last update: 12 January 2011
