Lung cancer risk associated with occupational exposure to nickel, chromium VI, and cadmium in two population-based case-control studies in Montreal.

Cancer du poumon associé à l’exposition au nickel, au chrome VI et au cadmium dans le milieu de travail utilisant deux études populationnelles cas-témoins à Montréal. Au début des années 1990, le nickel, le chrome VI et le cadmium ont été classés en tant qu’agents cancérigènes de classe 1 par le CIRC (Centre International de Recherche sur le Cancer). Cependant, les résultats des études ayant permis la classification de ces métaux n’ont pas toujours été reproduits, et d’importantes questions demeurent quant aux effets de ces métaux à de faibles niveaux d’exposition. Un plus grand nombre de recherches empiriques est donc nécessaire afin de réaffirmer la cancérogénicité de ces agents, et d’identifier les circonstances dans lesquelles ils peuvent être néfastes. L'objectif de cette étude était d'explorer la relation entre l’exposition à un des métaux (soit le nickel, le chrome VI, ou le cadmium) et les risques subséquents de développer un cancer du poumon chez des travailleurs provenant de différents milieux de travail qui sont exposés à ces métaux à de différents degrés. Deux études cas-témoins de base populationnelle menées à Montréal ont fourni les données nécessaires pour examiner la cancérogénicité de ces métaux. La première étude était menée entre 1979 et 1986 chez des hommes âgés de 35 à 70 ans ayant un cancer dans l’un de 19 sites anatomiques de cancer sélectionnés. La seconde étude était menée entre 1996 et 2001 chez des hommes et des femmes âgés de 35 à 75 ans, avec un diagnostic de tumeur maligne au poumon. Dans ces deux études, les cas ont été recensés dans tous les hôpitaux de l'île de Montréal, tandis que les contrôles populationnels appariés par âge et stratifiés par sexe, ont été sélectionnés des listes électorales. Une entrevue avec chaque sujet a permis d'obtenir un historique d'emploi détaillé ainsi que des informations précises sur les facteurs de risques socio-économiques et personnels. Les descriptions de poste ont été évaluées par une équipe d'experts chimistes et hygiénistes afin de déterminer si le sujet a été exposé à chaque agent, et pour mesurer à la fois la concentration et la durée de chaque exposition, ainsi que l’exposition cumulative tout au long de la vie de chaque participant. Pour déterminer si une exposition à l’un des trois métaux en cause était associée à une augmentation de l'incidence du cancer du poumon, des données ont été analysées par régression logistique : des ajustements ont été effectués pour des facteurs de confusion pertinents incluant un historique détaillé du tabagisme. Des mesures catégoriques d'exposition cumulée ont été également analysées, ainsi que la modification des effets par le tabagisme. Les deux études ont été analysées séparément, puis par la suite combinées afin d'augmenter la puissance statistique. Les niveaux d'exposition mesurés dans cette population ne semblaient pas poser un excès de risque de cancer du poumon pour les travailleurs exposés au chrome VI. Cependant, ceux qui ont été exposés au nickel ont subi une augmentation significative du risque, et ce, quel que soit leur niveau d'exposition. Le risque de développer un cancer du poumon suite à une exposition au cadmium était élevé, mais pas de manière significative. Pour chacun des trois métaux, le risque de cancer du poumon était très élevé parmi les non-fumeurs, mais pas parmi les fumeurs. L’effet combiné du tabagisme et de l’exposition aux métaux était compatible avec un excès de risque additif. Cependant, les intervalles de confiance dans cette étude tendaient à être larges, et une faiblesse de puissance statistique peut limiter l’interprétation de certains résultats. Cette étude est unique dans la mesure où elle a fourni des preuves empiriques sur les risques de développer le cancer du poumon liés aux faibles niveaux d’exposition au nickel, au chrome VI, ou au cadmium provenant de divers contextes de travail. Dans la plupart des autres études, la majorité des expositions pertinentes n’ont pas été bien contrôlées. À l'inverse, cette étude a bénéficié de la collecte et de la disponibilité d'information détaillée concernant le tabagisme et d’autres facteurs de risque. Les résultats de cette étude ont d'importantes conséquences pour la santé publique, tant au niveau de la détermination des risques pour les travailleurs actuellement exposés à ces métaux, qu'au niveau de l’évaluation des risques pour la population en général, elle-même exposée à ces métaux par le biais de la pollution et de la fumée de cigarette. Cette analyse contribuera fort probablement à une réévaluation par le CIRC de la cancérogénicité de ces métaux. L'exploration de la relation entre les risques de cancer du poumon et l'exposition au nickel, au chrome VI et au cadmium est donc opportune et pertinente.

Mitigating high ‘equity capital’ risk exposure to ‘small cap’ sector in India: analysing ‘key factors of success’ for ‘Institutional Investors’ whilst Investing in small cap sector in India

This paper deals with the subject of mitigating high ‘Equity Capital’ Risk Exposure to ‘Small Cap’ Sector in India. Institutional investors in India are prone to be risk averse when it comes to investing in the small cap sector in India as they find the companies risky and volatile. This paper will help analyse ‘Key Factors of success’ for ‘Institutional Investors’ whilst investing in Small Cap sector in India as some of these Indian small cap stocks offer handsome returns despite economic downturn. This paper has been harnessed carefully under the influence of expert investors, which includes Benjamin Graham (Security Analysis); Warren Buffet; Philip Fisher (Common Stocks and Uncommon Profits); and Aswath Damodaran.

Valuing emerging markets companies : new approaches to determine the effective exposure to country risk

The aim of this paper is to propose new methods to measure the effective exposure to country risk of emerging-market companies. Starting from Damodaran (2003), we propose seven new approaches and a revised CAPM for emerging markets companies. The “Prospective Lambda” represents the effective exposure according to analysts’ estimates of growth. The “Relative Lambda” relies on the firm value estimated through a relative valuation. The “Retrospective Lambda” represents the ex-post effective exposure to country risk. The “Company Effective Risk Premium” is a generalization of the Retrospective Lambda, and expresses the premium effectively requested by investors to invest in that specific company in the past year. “The Actual Lambda” and the “Company Actual Risk Premium” represent, respectively, the actual exposure to country risk of a company and the actual premium requested by investors to invest in that specific company. The “Industry Lambda” reflects the median exposure to country risk of the industry in which the company belongs. We tested our new measures of exposure to country risk on the Latin American emerging markets companies according to the classification of the MSCI Emerging Markets Latin America Index. The results confirm that the new approaches can be effectively applied by financial analysts to stable-growth companies that operate in emerging markets and to mature markets companies that operate in emerging markets, providing with a more reliable estimate of both the premium effectively requested by investors in the past and the actual premium. Applying the new approaches, the cost of equity reflects the effective exposure of a company to country risk without being over- or underestimated, as is the case with other existing approaches.

Nasopharyngeal carriage of Staphylococcus aureus among imprisoned males from Brazil without exposure to healthcare: risk factors and molecular characterization

Background: Previous studies report high prevalence of Methicillin-resistant Staphylococcus aureus (MRSA) colonization among imprisoned populations. However, there are no data on that prevalence in Brazilian correctional institutions.Findings: We tested 302 male prisoners for nasopharyngeal colonization with Staphylococcus aureus from February 2009 through April 2010. The overall isolation rate of S. aureus was 16.5% (50/302). Men who had sex with men, users of inhalatory drugs and those with previous lung or skin diseases were more likely to be colonized with S. aureus. MRSA was isolated from 0.7% of subjects (2/302). The two Community-associated (CA)-MRSA belonged to ST5 but were unrelated based on the PFGE results. Both harbored SCCmec IV, and did not possess the Panton-Valentine Leukocidin gene.Conclusion: We found low prevalence of S. aureus and CA-MRSA among prisoners. MRSA isolates ST5 from two subjects harboured SCCmec IV and presented different PFGE patterns.

Musculoskeletal disorders in upper limbs in dental students: exposure level to risk factors

Aim: This study assessed the risk factors of undergraduate students to develop musculoskeletal disorders (MSD) in the upper limbs, regarding gender, type of dental clinical procedure, mouth region treated, and the four-handed dentistry practice. Methods: Dental students enrolled in the 8th semester in the Araraquara School of Dentistry, UNESP, Brazil, were photographed while practicing 283 dental procedures. The Rapid Upper Limb Assessment (RULA) method was used to evaluate the working postures of each student. The photographs were evaluated and a final risk score was attributed to each analyzed procedure. The prevalence of risk factors of developing MSD was estimated by point and by 95% confidence interval. The association between the risk factor of developing disorders and variables of interest were assessed by the chi-square test with a significance level of 5%. Results: The risk factors of developing MSD were high, regarding most dental procedures performed by the undergraduate students (score 5: 7.07%, CI95%: 4.08- 10.06%; score 6: 62.54%, CI95%: 56.90-68.18%). There was no significant association between the RULA final score and gender (p=0.559), and type of dental procedure (p=0.205), and mouth regions by arch (p=0.110) or hemi-arch (p=0.560), and the use of four-handed dentistry (p=0.366). Conclusions: It can be concluded that gender, type of dental clinical procedure, mouth region treated, and practice of four-handed dentistry did not influence the risk of developing MSD in the upper limbs among the dental students evaluated; however, they are at a high risk of developing such disorders.

Muskuloskeletal disorders in upper limbs in dental students: exposure level to risk factors

Aim: This study assessed the risk factors of undergraduate students to develop musculoskeletaldisorders (MSD) in the upper limbs, regarding gender, type of dental clinical procedure, mouthregion treated, and the four-handed dentistry practice. Methods: Dental students enrolled in the8th semester in the Araraquara School of Dentistry, UNESP, Brazil, were photographed whilepracticing 283 dental procedures. The Rapid Upper Limb Assessment (RULA) method was usedto evaluate the working postures of each student. The photographs were evaluated and a finalrisk score was attributed to each analyzed procedure. The prevalence of risk factors of developingMSD was estimated by point and by 95% confidence interval. The association between the riskfactor of developing disorders and variables of interest were assessed by the chi-square test witha significance level of 5%. Results: The risk factors of developing MSD were high, regardingmost dental procedures performed by the undergraduate students (score 5: 7.07%, CI95%: 4.08-10.06%; score 6: 62.54%, CI95%: 56.90-68.18%). There was no significant association betweenthe RULA final score and gender (p=0.559), and type of dental procedure (p=0.205), and mouthregions by arch (p=0.110) or hemi-arch (p=0.560), and the use of four-handed dentistry (p=0.366).Conclusions: It can be concluded that gender, type of dental clinical procedure, mouth regiontreated, and practice of four-handed dentistry did not influence the risk of developing MSD in theupper limbs among the dental students evaluated; however, they are at a high risk of developingsuch disorders.(AU).

Patterns of exposure to infectious diseases and social contacts in early life and risk of brain tumours in children and adolescents: an International Case-Control Study (CEFALO)

BACKGROUND Infectious diseases and social contacts in early life have been proposed to modulate brain tumour risk during late childhood and adolescence. METHODS CEFALO is an interview-based case-control study in Denmark, Norway, Sweden and Switzerland, including children and adolescents aged 7-19 years with primary intracranial brain tumours diagnosed between 2004 and 2008 and matched population controls. RESULTS The study included 352 cases (participation rate: 83%) and 646 controls (71%). There was no association with various measures of social contacts: daycare attendance, number of childhours at daycare, attending baby groups, birth order or living with other children. Cases of glioma and embryonal tumours had more frequent sick days with infections in the first 6 years of life compared with controls. In 7-19 year olds with 4+ monthly sick day, the respective odds ratios were 2.93 (95% confidence interval: 1.57-5.50) and 4.21 (95% confidence interval: 1.24-14.30). INTERPRETATION There was little support for the hypothesis that social contacts influence childhood and adolescent brain tumour risk. The association between reported sick days due to infections and risk of glioma and embryonal tumour may reflect involvement of immune functions, recall bias or inverse causality and deserve further attention.

Exposure to Radio-Frequency Electromagnetic Fields From Broadcast Transmitters and Risk of Childhood Cancer: A Census-based Cohort Study

We investigated the association between exposure to radio-frequency electromagnetic fields (RF-EMFs) from broadcast transmitters and childhood cancer. First, we conducted a time-to-event analysis including children under age 16 years living in Switzerland on December 5, 2000. Follow-up lasted until December 31, 2008. Second, all children living in Switzerland for some time between 1985 and 2008 were included in an incidence density cohort. RF-EMF exposure from broadcast transmitters was modeled. Based on 997 cancer cases, adjusted hazard ratios in the time-to-event analysis for the highest exposure category (>0.2 V/m) as compared with the reference category (<0.05 V/m) were 1.03 (95% confidence interval (CI): 0.74, 1.43) for all cancers, 0.55 (95% CI: 0.26, 1.19) for childhood leukemia, and 1.68 (95% CI: 0.98, 2.91) for childhood central nervous system (CNS) tumors. Results of the incidence density analysis, based on 4,246 cancer cases, were similar for all types of cancer and leukemia but did not indicate a CNS tumor risk (incidence rate ratio = 1.03, 95% CI: 0.73, 1.46). This large census-based cohort study did not suggest an association between predicted RF-EMF exposure from broadcasting and childhood leukemia. Results for CNS tumors were less consistent, but the most comprehensive analysis did not suggest an association.

Occupational exposure to magnetic fields and electric shocks and risk of ALS: The Swiss National Cohort

Amyotrophic lateral sclerosis (ALS) has been associated with exposures in so-called 'electrical occupations'. It is unclear if this possible link may be explained by exposure to extremely low-frequency magnetic fields (ELF-MF) or by electrical shocks. We evaluated ALS mortality in 2000-2008 and exposure to ELF-MF and electrical shocks in the Swiss National Cohort, using job exposure matrices for occupations at censuses 1990 and 2000. We compared 2.2 million workers with high or medium vs. low exposure to ELF-MF and electrical shocks using Cox proportional hazard models. Results showed that mortality from ALS was higher in people who had medium or high ELF-MF exposure in both censuses (HR 1.55 (95% CI 1.11-2.15)), but closer to unity for electrical shocks (HR 1.17 (95% CI 0.83-1.65)). When both exposures were included in the same model, the HR for ELF-MF changed little (HR 1.56), but the HR for electric shocks was attenuated to 0.97. In conclusion, there was an association between exposure to ELF-MF and mortality from ALS among workers with a higher likelihood of long-term exposure.

The effect of cumulating exposure to abacavir on the risk of cardiovascular disease events in patients from the Swiss HIV Cohort Study.

BACKGROUND Patients with HIV exposed to the antiretroviral drug abacavir may have an increased risk of cardiovascular disease (CVD). There is concern that this association arises because of a channelling bias. Even if exposure is a risk, it is not clear how that risk changes as exposure cumulates. METHODS We assess the effect of exposure to abacavir on the risk of CVD events in the Swiss HIV Cohort Study. We use a new marginal structural Cox model to estimate the effect of abacavir as a flexible function of past exposures while accounting for risk factors that potentially lie on a causal pathway between exposure to abacavir and CVD. RESULTS 11,856 patients were followed for a median of 6.6 years; 365 patients had a CVD event (4.6 events per 1000 patient years). In a conventional Cox model, recent - but not cumulative - exposure to abacavir increased the risk of a CVD event. In the new marginal structural Cox model, continued exposure to abacavir during the past four years increased the risk of a CVD event (hazard ratio 2.06, 95% confidence interval 1.43-2.98). The estimated function for the effect of past exposures suggests that exposure during the past 6 to 36 months caused the greatest increase in risk. CONCLUSIONS Abacavir increases the risk of a CVD event: the effect of exposure is not immediate, rather the risk increases as exposure cumulates over the past few years. This gradual increase in risk is not consistent with a rapidly acting mechanism, such as acute inflammation.

Parental demographic risk factors and occupational exposure to ionizing radiation for achondroplasia, thanatophoric and autosomal deletions in Texas, 1996--2002

Little is known about the etiology of Achondroplasia (AC), Thanatophoric Dwarfism (TD), and autosomal deletions (CD). These syndromes are due to fully penetrate genetic mutations, yet arise de novo, instead of being inherited. We examined the association between parental demographic characteristics and parental occupations with exposure to ionizing radiation and these birth defects. ^ We conducted a cross-sectional study and two case-control studies using a large database that was created by linking records from Texas Birth Defects Registry, Texas birth certificates and Texas fetal death certificates from 1996 to 2002. The first case-control study was matched on paternal age and examined 73 cases of AC and 43 cases of TD. The second case-control study was unmatched and examined 343 cases of autosomal deletion syndromes. ^ We used a job exposure matrix (JEM) to measure exposures to ionizing radiation in the workplace. This gives an estimate of the intensity and probability of exposure to ionizing radiation for each occupation and industry. ^ The prevalence rate of Achondroplasia, Thanatophoric Dwarfism and autosomal deletions was 0.36 per 10,000, 0.21 per 10,000, and 1.68 per 10,000 births respectively in Texas 1996–2002. ^ Older fathers had a strong increase in the risk of having offspring with AC or TD and a modest increase in the risk of CD. Fathers who were Black or Hispanic were less likely to have infants with AC or TD compared to Whites (adjusted POR=0.61; 95% CI 0.30, 1.26 and 0.44; 95% CI 0.27, 0.88, respectively). Black fathers and Hispanic mothers were also less likely to have infants with CD (adjusted POR=0.54; 95% CI 0.22, 1.35 and 0.62; 95% CI 0.39, 0.97). ^ After adjusting for other parental demographic factors, there was no significant relation between fathers exposure to ionizing radiation in the work place and AC or TD (adjusted OR=0.48; 95% CI 0.19, 1.25) and no significant relation between parental exposure to ionizing radiation in the work place and CD (adjusted OR=1.16; 95% CI 0.73, 1.85). ^ This is the first study to find an association between father's age and TD and CD and paternal race and AC or CD. Parental exposure to radiation for therapeutic or diagnostic indications was not measured, thus it can not be excluded as a cause of these birth defects. ^

An assessment of risk of osteogenic sarcoma from exposure to radium

The etiology of the vast majority of osteosarcoma deaths has not been explained. A possible explanation might be lifetime ingestion of radium from environmental sources which might give rise to differential risk. This study was an effort toward understanding the role of naturally occurring radium in the etiology of bone cancer. Furthermore, there was an interest in the interaction of between radionuclides and selenium; the latter believed to be a potential anticarcinogen.^ Two approaches were used to evaluate the association between environmental radium, selenium and osteogenic sarcoma: (1) spatial and temporal patterns of osteogenic sarcoma mortality in Texas were described for the period from 1969 to 1988; and (2) a case-control study was performed using 974 osteosarcoma deaths and category-matched controls selected from other deaths to evaluate the association between this disease and residency history as an indirect measure of radium and selenium exposures.^ Analyses and comparison of mortality in a population exposed to regions of elevated levels of radium 226,228 and elevated levels of selenium in drinking water with those in a matched control population have resulted in three observations: (1) there appeared to be a slight protective effect for residing in areas high in radium; (2) there were no significant differences between cases and controls when observed for length of residence or residence in urban/rural regions of high or low radium; and (3) although regions high in selenium appeared to have a decreased risk for bone cancer and urban areas in regions of elevated selenium showed an increased risk of bone cancer, these differences were not significant. ^

RESPIRATORY COMPENSATION MECHANISMS IN THE UPPER AND LOWER RESPIRATORY TRACTS OF AN ANIMAL MODEL AFTER SUBCHRONIC INHALATION EXPOSURE TO FORMALDEHYDE: IMPLICATIONS FOR TOXICOLOGY RISK ASSESSMENT (DEPOSITION, DOSE RECEIVED, RESPONSE)

The potential for significant human populations to experience long-term inhalation of formaldehyde and reports of symptomatology due to this exposure has led to a considerable interest in the toxicologic assessment of risk from subchronic formaldehyde exposures using animal models. Since formaldehyde inhalation depresses certain respiratory parameters in addition to its other forms of toxicity, there is a potential for the alteration of the actual dose received by the exposed individual (and the resulting toxicity) due to this respiratory effect. The respiratory responses to formaldehyde inhalation and the subsequent pattern of deposition were therefore investigated in animals that had received subchronic exposure to the compound, and the potential for changes in the formaldehyde dose received due to long-term inhalation evaluated. Male Sprague-Dawley rats were exposed to either 0, 0.5, 3, or 15 ppm formaldehyde for 6 hours/day, 5 days/week for up to 6 months. The patterns of respiratory response, deposition and the compensation mechanisms involved were then determined in a series of formaldehyde test challenges to both the upper and to the lower respiratory tracts in separate groups of subchronically exposed animals and age-specific controls (four concentration groups, two time points). In both the control and pre-exposed animals, there was a characteristic recovery of respiratory parameters initially depressed by formaldehyde inhalation to at or approaching pre-exposure levels within 10 minutes of the initiation of exposure. Also, formaldehyde deposition was found to remain very high in the upper and lower tracts after long-term exposure. Therefore, there was probably little subsequent effect on the dose received by the exposed individual that was attributable to the repeated exposures. There was a diminished initial minute volume response in test challenges of both the upper and lower tracts of animals that had received at least 16 weeks of exposure to 15 ppm, with compensatory increases in tidal volume in the upper tract and respiratory rate in the lower tract. However, this dose-related effect was probably not relevant to human risk estimation because this formaldehyde dose is in excess of that experienced by human populations. ^

Probabilistic meta-analysis of risk from the exposure to Hg in artisanal gold mining communities in Colombia

Colombia is one of the largest per capita mercury polluters in the world as a consequence of its artisanal gold mining activities. The severity of this problem in terms of potential health effects was evaluated by means of a probabilistic risk assessment carried out in the twelve departments (or provinces) in Colombia with the largest gold production. The two exposure pathways included in the risk assessment were inhalation of elemental Hg vapors and ingestion of fish contaminated with methyl mercury. Exposure parameters for the adult population (especially rates of fish consumption) were obtained from nation-wide surveys and concentrations of Hg in air and of methyl-mercury in fish were gathered from previous scientific studies. Fish consumption varied between departments and ranged from 0 to 0.3 kg d?1. Average concentrations of total mercury in fish (70 data) ranged from 0.026 to 3.3 lg g?1. A total of 550 individual measurements of Hg in workshop air (ranging from menor queDL to 1 mg m?3) and 261 measurements of Hg in outdoor air (ranging from menor queDL to 0.652 mg m?3) were used to generate the probability distributions used as concentration terms in the calculation of risk. All but two of the distributions of Hazard Quotients (HQ) associated with ingestion of Hg-contaminated fish for the twelve regions evaluated presented median values higher than the threshold value of 1 and the 95th percentiles ranged from 4 to 90. In the case of exposure to Hg vapors, minimum values of HQ for the general population exceeded 1 in all the towns included in this study, and the HQs for miner-smelters burning the amalgam is two orders of magnitude higher, reaching values of 200 for the 95th percentile. Even acknowledging the conservative assumptions included in the risk assessment and the uncertainties associated with it, its results clearly reveal the exorbitant levels of risk endured not only by miner-smelters but also by the general population of artisanal gold mining communities in Colombia.

Probabilistic assessment of risk from the exposure to mercury in artisanal gold mining communities in Colombia

Colombia is one the largest per capita mercury polluters as a consequence of its artisanal gold mining operations, which are steadily increasing following the rising price of this metal. Compared to gravimetric separation methods and cyanidation, the concentration of gold using Hg amalgams presents several advantages: the process is less time-consuming and minimizes gold losses, and Hg is easily transported and inexpensive relative to the selling price of gold. Very often, mercury amalgamation is carried out on site by unprotected workers. During this operation large amounts of mercury are discharged to the environment and eventually reach the fresh water bodies in the vicinity where it is subjected to methylation. Additionally, as gold is released from the amalgam by heating on open charcoal furnaces in small workshops, mercury vapors are emitted and inhaled by the artisanal smelters and the general population