Search

The issue of radiation exposure as a potential cause of cerebrovascular disease raises many concerns. The aim of the present study was to investigate the epidemiology of stroke and transient ischemic attacks (TIA) along with the associated risk factors among the population of East Kazakhstan exposed to ionising radiation from the former Semipalatinsk Nuclear Test Site (SNTS) in comparison with the unexposed population of the same region. This 5-year retrospective cross-sectional study included the data on 10,970 patients, of whom the majority (62.3%) suffered from ischemic stroke, 11.7% had hemorrhagic stroke and the remaining 26.0% had TIA. At the moment when stroke/TIA happened, exposed patients were younger than the unexposed (mean age 63 years versus 64 years, p

ObjectivesThe increase in production of multiwalled carbon nanotubes (MWCNTs) has led to growing concerns about health risks. In this study, we assessed the association between occupational exposure to MWCNTs and cardiovascular biomarkers.MethodsA cross-sectional study was performed among 22 workers of a company commercially producing MWCNTs (subdivided into lab personnel with low or high exposure and operators), and a gender and age-matched unexposed population (n=42). Exposure to MWCNTs and 12 cardiovascular markers were measured in participants’ blood (phase I). In a subpopulation of 13 exposed workers and six unexposed workers, these measures were repeated after 5 months (phase II). We analysed associations between MWCNT exposure and biomarkers of cardiovascular risk, adjusted for age, body mass index, sex and smoking.ResultsWe observed an upward trend in the concentration of endothelial damage marker intercellular adhesion molecule-1 (ICAM-1), with increasing exposure to MWCNTs in both phases. The operator category showed significantly elevated ICAM-1 geometric mean ratios (GMRs) compared with the controls (phase I: GMR=1.40, P=1.30E-3; phase II: GMR=1.37, P=0.03). The trends were significant both across worker categories (phase I: P=1.50E-3; phase II: P=0.01) and across measured GM MWCNT concentrations (phase I: P=3.00E-3; phase II: P=0.01). No consistent significant associations were found for the other cardiovascular markers.ConclusionThe associations between MWCNT exposure and ICAM-1 indicate endothelial activation and an increased inflammatory state in workers with MWCNT exposure.

In the 1980s, villages in the Kurdistan region of Iraq were exposed to chemical weapons (CWs), which killed and injured thousands of civilians. There has been no clinical assessment of the long-term effects of CWs exposure on those injured. We report the first such evaluation of CW effects on long-term health of children. Patients from the CW-exposed areas were interviewed to assess previous and current clinical history and underwent clinical examination. The status of organs known to be targets of CWs, including skin, eyes, respiratory and neuromuscular systems, was assessed. Children of similar age and social background, but with no history of CW exposure, were selected as a control population. Results showed that 70% of children in the CWs group had chronic health problems in contrast to 3.3% in the unexposed group ( p < 0.0001). Fifty-five per cent of the CW-exposed group had long-term visual impairment but none in the unexposed population. Thirty-six per cent of the CW-exposed group had chronic dermatological conditions compared with 0.8% of the unexposed group ( p < 0.0001), 31% of the CWs group had neurological sequelae compared with 0.4% of the unexposed group ( p < 0.0001) and 51% of the CWs group had long-term respiratory problems compared with 1.5% of the unexposed group ( p < 0.0001). Respiratory complaints including asthma, chronic bronchitis and bronchiectasis were particularly common. Our study suggests that CWs used were probably a combination of sulphur mustard and organophosphate nerve agents. Results also indicate that the prevalence of acute and chronic health problems following exposure to CW agents appear to be higher in children compared with reported data in adults.

Estimating the population attributable fraction (PAF) of melanomas due to sun exposure is challenging as there are no unexposed population nor reliable exposure data. In high incidence countries, a historic cohort of the South Thames cancer registry was used as a minimally exposed population using the formula PAF = (observed incidence-incidence in minimally exposure)/observed incidence. In this study, we apply this method, constructing a minimally exposed cohort for Colombia and also using the historical South Thames data, using melanoma incidence data from the population-based cancer registry of Cali, Colombia for the period 1967-2012. The historic cohort incidence rates were very similar to those of Thames, but cohort effects were smaller for women and nonexistent for men. Age-specific incidence rates of these minimally exposed cohorts were applied to recent population numbers. For females, PAFs were 19% using the historic Thames cohort and 25% using the historic Cali cohort, corresponding numbers for males were 62% (vs. Thames) and 0% (vs. Cali). Taking into account the incidence rates of acral melanomas, which are not sun related, the PAF increased in women to 26% (vs. Thames) and 34% (vs. Cali) and for men 77% (vs. Thames). This exercise shows the modest contribution of exposure to ultraviolet radiation in the burden of melanoma in low-incidence countries, as well as the importance to take into consideration the acral lentiginous melanomas.

Purpose: Vertebral hemangiomas (VHs) are the most common benign tumors of the spine that may cause bone resorption. Megavoltage irradiation is usually the treatment of choice for the management of symptomatic VHs. The current study was conducted to estimate the risk for carcinogenesis from radiotherapy of this benign disease on the basis of the calculated radiation doses to healthy organs. Methods: The Monte Carlo N-particle transport code was employed to simulate the irradiation with 6 MV x-rays of a VH presented in the cervical, upper thoracic, lower thoracic, and lumbar spine. The average radiation dose (Dav) received by each critical organ located outside the primarily irradiated area was calculated. Three-dimensional treatment plans were also generated for the VHs occurring at the four different sites of the spinal cord based on patients’ computed tomography data. The organ equivalent dose (OED) to each radiosensitive structure, which was partly encompassed by the applied treatment fields, was calculated with the aid of differential dose–volume histograms. The Dav and the OED values were combined with a linear-no-threshold model and a nonlinear mechanistic model, respectively, to estimate the organ-, age-, and gender-specific lifetime attributable risks (LARs) for cancer development. The estimated risks were compared with the respective nominal lifetime intrinsic risks (LIRs) for the unexposed population. Results: For a standard target dose of 34 Gy, the OED varied from 0.39–5.15 Gy by the organ of interest and the irradiation site. The Dav range for the out-of-field organs was 4.9 × 10−4 to 0.56 Gy. The LAR for the appearance of malignancies in the partially in-field organs after radiotherapy of male and female patients was (0.08%–1.8%) and (0.09%–1.9%), respectively. These risk values were 1.5–15.5 times lower when compared to the respective LIRs. The lifetime probability for out-of-field cancer induction in irradiated males and females was (2.5 × 10−4 to 7.7 × 10−2)% and (1.4 × 10−4 to 2.6 × 10−1)%, respectively. The above risks were one to four orders of magnitude lower than the LIRs. Conclusions: The probability for the development of out-of-field malignancies due to radiotherapy for VHs is trivial with respect to the nominal risk for unexposed population. The respective cancer risks to partially in-field organs are smaller than the nominal probabilities but they should not be considered as inconsiderable. These risks may be taken into account during the follow-up of patients treated for a symptomatic VH.

Purpose To assess the risk of contralateral breast and ipsilateral lung cancer induction from forward-planned IMRT for breast carcinoma. Methods The study group included 13 females irradiated for breast cancer with 6 MV photons. The plans were initially generated by using standard fractionated (SF) forward-planned IMRT (50 Gy at 2 Gy/fraction). Hypofractionated (HF) IMRT (42.56 Gy at 2.66 Gy/fraction) was also employed for plan creation. Differential DVHs derived from the treatment plans were used to estimate the patient-specific organ equivalent dose (OED) to the contralateral breast and ipsilateral lung and the relevant lifetime attributable risks of cancer development. These estimates were made with a non-linear mechanistic model. The radiotherapy-induced cancer risks were combined with the lifetime intrinsic risk (LIR) values for unexposed people to determine the patient- and organ-specific relative risk (RR) for second cancer induction. Results The OED of the contralateral breast from SF and HF forward-planned IMRT was up to 0.99 and 0.86 Gy, respectively. The corresponding values for the ipislateral lung were 4.15 and 3.66 Gy. The patient-specific RR range for the contralateral breast and ipislateral lung cancer induction following SF forward-planned IMRT was 1.04–1.10 and 1.60–1.81, respectively. The corresponding RRs from hypofractionated treatment were 1.03–1.09 and 1.53–1.73. Conclusions The treatment of primary breast carcinoma with the use of SF or HF forward-planned IMRT results in increased probabilities for developing secondary malignancies in the healthy contralateral breast or ipsilateral lung compared to the respective LIRs for an unexposed population.

Traditional environmental risk assessment methodologies, including benchmark dose (BMD) estimation, were originally developed to be used with animal toxicology data. We discuss some problems that can occur when toxicology-based methods are applied to human cohort studies, and we propose a new method for BMD risk estimation adapted to epidemiological data. Instead of extrapolating to zero-dose levels to estimate risk in an unexposed population, our proposed alternative involves specifying a nonzero background exposure level instead. To account for uncertainty in that level, we can average modified BMDs over a distribution of exposure levels. We apply our modified BMD method to analyze data from a cohort study designed to assess the effects of prenatal polychlorinated biphenyl (PCB) exposure on cognitive ability in young children. Copyright © 2013 John Wiley & Sons, Ltd.

Arsenic Exposure through Drinking Water and its Effect on Pregnancy Outcome in Bengali WomenTwelve districts of the state of West Bengal, India are affected by arsenic (As) and millions of individuals are consuming As-contaminated groundwater. The probable adverse effects of As on pregnancy outcome (stillbirth and miscarriage) are yet to be properly studied. The present investigation is an attempt to understand the effects of As exposure on the pregnancy outcome in Bengali women exposed to As through drinking water and residing in different villages in North 24 Parganas District of West Bengal. The results show a significantly higher rate of stillbirths and miscarriages than those in the unexposed population.

Purpose There are a limited number of case reports confirming the radioiodine (I-131) presence in tears and only a few case reports of lacrimal gland dysfunction after I-131 therapy. This study was designed to clarify whether lacrimal gland function can be affected by I-131 therapy. Materials and methods We studied 100 eyes of 50 patients who had received high doses of I-131 for treatment of differentiated thyroid carcinoma and 100 eyes of 50 age- and sex-matched control individuals without a history of interfering conditions. The exposed group was studied at least 3 months after their last I-131 therapy. Dry eye symptoms and Schirmer test values (wetting level in millimeters per 5 minutes) of an exposed group were compared with those of an unexposed group. Results Fifty-one percent of the exposed eyes and 50% of the unexposed ones revealed at least 1 of the dry eye symptoms. There was no significant difference in symptoms between 2 groups, except for burning sensation and eye redness, which were significantly higher in the exposed eyes. A lower Schirmer test value was noted in the exposed group, 14.5 +/- 10.8 mm, when compared with that in controls, 18.2 +/- 11.0 mm (P = 0.016), and the relative risk of an abnormal Schirmer test in exposed cases to control group was 1.78 +/- 0.62. Correlation coefficient analysis showed no significant relationship between Schirmer test values and cumulative doses of administered I-131. Conclusions Reduction in the tear secretion from lacrimal glands is seen after high-dose I-131 therapy; however, their symptoms are no greater than an unexposed population.

Objectives This study aimed at developing a model for determining the work-relatedness of low-back pain for a worker with low-back pain using both a personal exposure profile for well-established risk factors and the probability of low-back pain if the worker were unexposed to these factors. Methods After a systematic review of the literature, the pooled prevalence of low-back pain in an unexposed population and the pooled odds ratio (OR) for each risk factor was calculated in a meta-analysis using a random effect model. An unbiased risk estimate for each risk factor was obtained by correcting the pooled OR for confounding by other risk factors. The probability of low-back pain was calculated with a logistic regression model. The input was (i) the age-dependent prevalence when not exposed and (ii) the unbiased risk estimates per risk factor of low and high exposure. The etiologic fraction was calculated to determine the level of work-relatedness. Results The pooled prevalence for low-back pain among unexposed subjects was 22%, 30%, and 34% for the＜35-year, 35-to-45-year, and ＞45-year age categories, respectively. The pooled OR was 1.51 [95% confidence interval (95% CI) 1.31-1.74] for manual materials handling, 1.68 (95% CI 1.41-2.01) for frequent bending or twisting, 1.39 (95% CI 1.24-1.55) for whole-body vibration, and 1.30 (1.17-1.45) for job dissatisfaction. For high exposure to manual materials handling, frequent bending or twisting, and whole-body vibration, the pooled OR was 1.92, 1.93, and 1.63, respectively. Conclusions The model is the first that estimates the probability of work-relatedness for low-back pain for a given worker with low-back pain seen by a general practitioner or an occupational health physician.

This study was conducted to investigate the possible long-term health effects, in particular carcinogenic effects, of occupational exposure to the organochlorine insecticides dieldrin and aldrin. We updated an earlier cohort mortality study of 570 employees involved in the production of these insecticides. All of the employees had worked in the production plants between 1 January 1954 and 1 January 1970 and were followed for cause-specific mortality until 1 January 2001. Based on dieldrin levels in blood samples taken during the exposure period, available for 343 workers, individual estimates of the total intake of dieldrin were estimated for all individual subjects in the cohort. The estimated total intake ranged from 11 to 7755 mg of dieldrin, with an average of 737 mg. One hundred and seventy-one workers had died before 1 January 2001, compared with an expected number of 226.6, giving a standardized mortality ratio (SM R) of 75.6 [95% confidence interval (CI): 64.6-87.7]. This deficit in total mortality was mainly attributable to a deficit in cardiovascular disease mortality, but cancer mortality was also lower than expected. The observed number of deaths from rectal cancer was significantly higher than expected (SM R 3/4-300.0; 95% CI: 109.5-649.3), but was most pronounced in the low-intake subgroup and appears to be unrelated to exposure to dieldrin and aldrin. This study reinforces the earlier findings that occupational exposure of workers to significant amounts of dieldrin and aldrin has not led to a higher cancer mortality than would be found in an unexposed population.

Objectives: to know the effect participation in prenatal class to the practice of early initiation breastfeeding in Sisir health care center-Batu. Materials and Methods: This research was an analytical study with cohort retrospective design. The population in this study was divided into two populations, exposed populations were mothers who attend prenatal classes during the last pregnancy and unexposed population were mothers never attend prenatal classes. Sample size was 32 respondent. Data were analyzed by chi square test. Results: The results of the bivariate analysis of age (p value = 0.229), education (p value = 0.1790, parity (p value = 0.011), knowledge (p value = 0.047), attitude (p value = 0.893), history of labor (p value = 0,021), information (p value = 0.472), birth attendants (p value = 0.017), the place of delivery (p value = 0.003), participation in prenatal classes (p value = 0.27), decision makers (p value = 0.137), counseling during pregnancy (0.16) The analysis showed significant variable is the parity (p = 0.011), knowledge (p = 0.047), birth attendants (p = 0.017), the place of delivery (0.003), history of labor (p = 0.021), counseling during pregnancy (p = 0.010). Conclusion: There is no effect of the mother's participation in the prenatal class to the practice of early initiation breastfeeding, but the prenatal classes effect mothers knowledge which influence the practice of early initiation breastfeeding.

While blood lead levels (BLLs) in many western countries have progressively declined since 1976, in Nigeria high BLL continue to be documented not only in exposed workers but also in "unexposed" control subjects. The problem of environmental lead exposure has hitherto gone unaddressed by both researchers and health policy makers in Nigeria despite the immense public health importance. Continued high BLLs in Nigeria cast doubt on researchers' ability to find real "unexposed control subjects" in future studies, and point to the importance of controlling environmental lead exposures.

The recent article, “Analyses of Radiation and Mesothelioma in the US Transuranium and Uranium Registries,” by Gibb et al.1 examines seven mesothelioma deaths among a small population of 329 deceased registrants in the US Transuranium and Uranium Registries (USTUR). Using the National Institute for Occupational Safety and Health’s Life Table Analysis System with the referent group being all deaths in the United States,2,3 the study finds a proportionate mortality ratio (PMR) of 62.40 (P

The element lead (Pb) has been very widely studied in man due to its widespread occurrence and toxic effects. There is no known nutritional value of Pb and it is stored in the bone by replacing calcium. In the cellular level, Pb alters cell membrane structure and membrane on function. It is a potent inhibitor of the Na{sup +} K{sup +} ATPase. Pb also interferes with the activity of the enzymes delta-aminoevulinic acid synthetase, delta-aminolevulinic dehydrase and intra-mitochondrial ferrochelatase. In the pre-natal level, Pb-exposure may lead to an increased risk of prematurity and reduction of gestational age in humans. Pb-exposure causes adverse neuro-psychological effects among young children and numerous endrocrinal disturbances among adults. It has shown that Human Scalp Hair (HSH) Pb concentration can be used very successfully to document population exposure to this toxic element. Copper is known to be biologically essential, but Cu poisoning is rare in humans. This study attempts to document exposure and to determine `base-line` values for HSH Pb and CU among three occupationally unexposed population groups in Calcutta. 15 refs., 1 tab.

Summary Background Several reports of limb defects occurring among infants exposed to chorionic villus sampling (CVS) during pregnancy resulted in concern about the safety of this procedure for prenatal diagnosis. To avoid publication bias and evaluate the true risk of limb defects in a CVS cohort, the World Health Organization initiated international registration of post-CVS limb defects in 1992. Methods From May, 1992, to May, 1994, 77 infants or fetuses with limb defects from 138 996 pregnancies having CVS were reported to the WHO CVS Registry. These cases were analysed by standardised methods-ie, exclusion of syndromes, inherited disorders, and defects occurring in previable fetuses. The included limb deficiencies were studied by pattern analysis. Findings Defects of the upper limbs were reported in 64·6%, of the lower limbs in 12·5%, and of both upper and lower limbs in 20·8% of cases. These figures are in agreement with the distribution of limb defects in several large population-based studies. Transverse limb defects occurred in 40·8% and longitudinal defects in 59·2%, compared with 42·7% and 57·3% in an unexposed population. Interpretation The analysis of this cohort did not show any differences from the background population in the overall frequency or pattern distribution of limb deficiencies. There was also no correlation between gestational age at CVS and severity of defects. Therefore these results do not indicate any increased risk of limb defects after CVS.

In an evaluation of 30 patients with head and neck cancer, we found that 14 (46%) were uninsured at the time of diagnosis and 15 (50%) had yearly incomes below the poverty level. Tobacco and alcohol were identified as risk factors in 25 (83%) of the patients. These patients spent an average of $2,781 on carcinogenic agents yearly, increasing the risk of cancer 55 times that of the unexposed population, whereas the cost of a health insurance policy was $2,321 per year. To remedy the disparities and incongruities of this situation, we advocate patient education to influence behavioral change in these high-risk groups, a lowering of insurance rates, legal reform, and continued physician activism toward managing the current health care crisis.

International audience; BACKGROUND: Persistent symptoms, mainly joint and muscular pain and depression, have been reported several months after Chikungunya virus (CHIKV) infection. Their frequency and their impact on quality of life have not been compared with those of an unexposed population. In the present study, we aimed to describe the frequency of prolonged clinical manifestations of CHIKV infection and to measure the impact on quality of life and health care consumption in comparison with that of an unexposed population, more than one year after infection. METHODOLOGY/PRINCIPAL FINDINGS: In a retrospective cohort study, 199 subjects who had serologically confirmed CHIKV infection (CHIK+) were compared with 199 sero-negative subjects (CHIK-) matched for age, gender and area of residence in La Réunion Island. Following an average time of 17 months from the acute phase of infection, participants were interviewed by telephone about current symptoms, medical consumption during the last 12 months and quality of life assessed by the 12-items Short-Form Health Survey (SF-12) scale. At the time of study, 112 (56%) CHIK+ persons reported they were fully recovered. CHIK+ complained more frequently than CHIK- of arthralgia (relative risk = 1.9; 95% confidence interval: 1.6-2.2), myalgia (1.9; 1.5-2.3), fatigue (2.3; 1.8-3), depression (2.5; 1.5-4.1) and hair loss (3.8; 1.9-7.6). There was no significant difference between CHIK+ and CHIK- subjects regarding medical consumption in the past year. The mean (SD) score of the SF-12 Physical Component Summary was 46.4 (10.8) in CHIK+ versus 49.1 (9.3) in CHIK- (p = 0.04). There was no significant difference between the two groups for the Mental Component Summary. CONCLUSIONS/SIGNIFICANCE: More than one year following the acute phase of infection, CHIK+ subjects reported more disabilities than those who were CHIK-. These persistent disabilities, however, have no significant influence on medical consumption, and the impact on quality of life is moderate.

Odds ratios (OR) are commonly reported in the medical literature as the measure of association between exposure and outcome. However, it is relative risk that people more intuitively understand as a measure of association. Relative risk can be directly determined in a cohort study by calculating a risk ratio (RR). In case-control studies, and in cohort studies in which the outcome occurs in less than 10% of the unexposed population, the OR provides a reasonable approximation of the RR. However, when an outcome is common (iY 10% in the unexposed group), the OR will exaggerate the RR. One method readers can use to estimate the RR from an OR involves using a simple formula. Readers should also look to see that a confidence interval is provided with any report of an OR or RR. A greater understanding of ORs and RRs allows readers to draw more accurate interpretations of research findings.

The molecular mechanisms that result in the elevated risk for lung cancer associated with exposure to radiation have not been well characterized. Workers from the MAYAK nuclear enterprise are an ideal cohort in which to study the molecular epidemiology of cancer associated with radiation exposure and to identify the genes targeted for inactivation that in turn affect individual risk for radiation-induced lung cancer. Epidemiology studies of the MAYAK cohort indicate a significantly higher frequency for adenocarcinoma and squamous cell carcinoma (SCC) in workers than in a control population and a strong correlation between these tumor types and plutonium exposure. Two hypotheses will be evaluated through the proposed studies. First, radiation exposure targets specific genes for inactivation by promoter methylation. This hypothesis is supported by our recent studies with the MAYAK population that demonstrated the targeting of the p16 gene for inactivation by promoter methylation in adenocarcinomas from workers (1). Second, genes inactivated in tumors can serve as biomarkers for lung cancer risk in a cancer-free population of workers exposed to plutonium. Support for this hypothesis is based on exciting preliminary results of our nested, case-control study of persons from the Colorado cohort. In that study, a panel of methylation markers more » for predicting lung cancer risk is being evaluated in sputum samples from incident lung cancer cases and controls. The first hypothesis will be tested by determining the prevalence for promoter hypermethylation of a panel of genes shown to play a critical role in the development of either adenocarcinoma and/or SCC associated with tobacco. Our initial studies on adenocarcinoma in MAYAK workers will be extended to evaluate methylation of the PAX5 {alpha}, PAX5 {beta}, H-cadherin, GATA5, and bone morphogenesis 3B (BMP3B) genes in the original sample set described under Preliminary studies. In addition, studies will be initiated in SCC from workers and controls to identify genes targeted for inactivation by plutonium in this other common histologic form of lung cancer. We will examine methylation of the p16, O{sup 6}-methylguanine-DNA methyl-transferase (MGMT), and death associated protein kinase genes ([DAP-K], evaluated previously in adenocarcinomas) as well as the new genes being assessed in the adenocarcinomas. The second hypothesis will be tested in a cross-sectional study of cancer-free workers exposed to plutonium and an unexposed population. A cohort of 700 cancer-free workers and 700 unexposed persons is being assembled, exposures are being defined, and induced sputum collected at initial entry into the study and approximately 1-year later. Exposed and unexposed persons will be matched by 5-year age intervals and smoking status (current and former). The frequency for methylation of four genes that show the greatest difference in prevalence in tumors from workers and controls will be determined in exfoliated cells within sputum. These studies will extend those in primary tumors to determine whether difference in prevalence for individual or multiple genes are detected in sputum samples from high-risk subjects exposed to plutonium. Follow-up of this cohort offers the opportunity to validate these endpoints and future biomarkers as true markers for lung cancer risk. « less

The present paper reviews the American epidemic of West Nile Fever (WNF), which is the largest recorded outbreak ever. The epidemiological consequences of introducing a novel and immunologically unknown pathogen in a previously unexposed population and the possible evolution of a more pathogenic viral strain are discussed. In view of recent reports of imported cases in Denmark the issue of possible disease spread to Scandinavia is likewise addressed. However, the main scope of the article is to provide the clinician with an overview of the natural history, epidemiology and clinical characteristics of the disease.

Objectives Evaluation of the clinical impact of chronic exposure to perchlorethylene in west Algeria. Method After protocol definition, inclusion of salaries for three pressings willayas the west Algeria (Sidi Bel Abbes, Oran and Ain Temouchent), we conducted a study papers / unexposed to evaluate the clinical symptoms with matching on age and sex. 55Data collection made by a questionnaire (one of Hogstedt). Were conducted psychometric tests. The evaluation of occupational exposure by air sampling was carried out in two pressings using colorimetric detector tubes for spot metering (Dragger pumps). The first in any point in the space, the second opening when the window. Results Sixty employees and 120 controls were included. 50% of employees often have fatigue at the end of work against it are more than 50% sometimes complain of fatigue at the beginning and at the workplace and irritability. There is a significant difference between exposed and unexposed population on the presence of clinical signs except for the presence of three signs: nightmares, tingling in arms and digestive disorders. There is a significant difference between the two populations for all the psychometric tests. Perchlorethylene air rate upon opening of the window is greater than or equal to 100 ppm and both are higher than the limit value ACGIH 2005 Conclusions This study confirms the existence of an occupational exposure to perchlorethylene dry cleaners or employees of the questionnaire results allowed us to identify a number important information on the symptoms observed in the study population according to exposure.

Farm workers in developing countries tend not to use protective measures while handling pesticides. This study investigates the use of personal protection equipment and the practice of safety and hygiene procedures in the handling of pesticides in agriculture. Methods: Through a multi-stage sampling technique, one-fifth of the farms in a region were selected and all the farm workers at these farms were included in the study. A comparison population matching in age, socio-economic status and stay in the region was selected. A specifically designed questionnaire was used to collect information on the use of protective measures and the practice of safety and hygiene during work and on the disposal of empty pesticide containers. Blood pressure and erythrocyte acetylcholinesterase (AChE) activity were measured in the exposed and the unexposed populations. Results: Protective equipment was worn by a minority of farm workers – gloves, by 35%; work coveralls, by 36%; a scarf to cover the nose and mouth, by 39%; and shoes at work, by 79%. With regard to personal hygiene measures, 83% of the workers changed clothes after work and the same proportion took a shower after work; 63% and 46% drank and ate while at work respectively; and 11% used articles of domestic use in the preparation of pesticides on the farm. Most of the farm workers (96%) were asked to prepare pesticides for spraying by the foreman and 61% were asked to spray the pesticides on the crops. AChE activity was highly significantly depleted in the exposed population as compared with the unexposed population. Conclusions: AChE depletion was found to be negatively associated with the use of gloves, of work coveralls, and of a scarf to cover the nose and mouth and with the implementation of safety and hygiene procedures on the farm. AChE depletion was positively associated with the frequency of pesticide spraying.

The Blomia genus has been described as allergenic in man. The present study aimed to assess the prevalence of B. kulagini sensitization in a large population of allergic subjects without occupational exposure in a subtropical region (Canary Islands, Spain). Secondarily, a new standardized B. kulagini extract was evaluated. The study population comprised 207 patients. RAST for B. kulagini was positive in 76.2% of patients, and 47 of them were selected for the biologic standardization. When the prick test was performed with the nonstandardized extracts, results were positive in 76.6%, whereas when the test was repeated with the standardized extract, sensitivity rose to 95.7%. The conjunctival provocation test was positive in 78.3% of 46 evaluated patients. The bronchial provocation test was positive in 18 sensitized patients and negative in five controls. In conclusion, B. kulagini is an important cause of sensitization among the occupationally unexposed population of the studied area and should be included in allergy diagnostic tests. For reliable prick tests, the use of standardized extracts is mandatory.

Publisher Summary This chapter discusses the excess risk of sinonasal cancer among workers exposed to wood dust. The quantification of the association between the disease and exposure is given as a relative risk (RR), which is the risk among exposed subjects divided by the risk among the unexposed population. For descriptive studies, the measure used is a comparison between the exposed subjects and the general population, which comprises both exposed and unexposed subjects. If there is no association, the observed figure is close to one, irrespective of the measure used. Relative risk for sinonasal cancer was given by the wood-related occupational category, separately for adenocarcinoma and squamous cell cancer. For adenocarcinomas among men, a high relative risk was associated with employment in wood-related jobs (RR = 13.5). The risk was found to be higher among furniture workers (RR = 41.1). The relative risk was lower than one for forestry, logging, and pulp, and paper workers. No association was observed among men between squamous cell carcinoma and employment in all wood-related occupations (RR = 0.8). The chapter shows the analysis among men by level of wood dust exposure indicating a clear relationship between the risk of adenocarcinoma and the level of exposure, with a RR of 45.5 for high exposure.

Objectives Animal studies and clinical trials have examined the potential benefits of statins in asthma management with contradictory results. The objective of this study was to determine if asthma patients on concurrent statins are less likely to have asthma-related hospitalisations. Design A retrospective cohort study using Mississippi Medicaid data for 2002–2004. Participants Asthma patients ≥18 years were identified using the ICD9 code 493.xx from 1 July 2002 through 31 December 2003. The index date for an exposed subject was any date within the identification period, 180 days prior to which the subject had at least one inhaled corticosteroid prescription and at least an 80% adherence rate to statins. Asthma patients on inhaled corticosteroids, but not on statins, were selected as the unexposed population. The two groups were matched and followed for 1 year beginning the index date. Main outcomes measures Patient outcomes in terms of hospitalisations and ER visits were compared using conditional logistic regression. Results After matching, there were 479 exposed subjects and 958 corresponding unexposed subjects. The odds of asthma-related hospitalisation and/or emergency room (ER) visits for asthma patients on concurrent statins were almost half the odds for patients not on statins (OR=0.55; 95% CI (0.37 to 0.84); p=0.0059). Similarly, the odds of asthma-related ER visits were significantly lower for patients on statins (OR=0.48; 95% CI (0.28 to 0.82); p=0.0069). Conclusion The findings suggest beneficial effects of statins in asthma management. Further prospective investigations are required to provide more conclusive evidence., Article summary Article focus Statins have been shown to have promising therapeutic potential in mediating anti-inflammatory processes in animal model studies as well as clinical trials of rheumatoid arthritis, autoimmune encephalomyelitis, inflammatory colitis and psoriasis. Along the same line of reasoning, recently there has been some discussion regarding the use of statins in asthma management in addition to inhaled corticosteroid therapy. The purpose of this study was to investigate the beneficial effects of statins on asthma outcomes using the Mississippi Medicaid claims database. Key messages The findings suggest that statins may be beneficial in asthma management. The study accounts for several additional potential confounders not previously explored in the other observational studies. Strengths and limitations of this study The study uses a propensity score-matched cohort study design, which in itself should take into account potential confounding effects. The study was conducted using Medicaid claims data, and therefore, there is a possibility of misclassification due to coding errors during claims processing.

As part of a study on health effects of naphtha exposure, the association between naphtha exposure and urinary excretion of total protein, albumin, beta-N-acetyl-D-glucosaminidase (beta-NAG), and beta 2-microglobulin was assessed prospectively over 1 year among workers at an automotive plant that used naphtha to calibrate fuel injectors. Participants consisted of 248 workers who provided spot urine samples in June 1988 among whom 181 workers provided specimens again in June 1989. Naphtha air concentrations at the plant ranged from 6 to 790 mg/m3 and the length of exposure ranged from 0.8 to 7.3 years. In both 1988 and 1989, the overall distribution of the four measures of renal function appeared consistent with that of an unexposed population. In cross-sectional analyses, there were no statistically significant associations in the expected direction between cumulative or recent naphtha exposure and the measures of renal function. In longitudinal analyses, the change in beta-NAG was positively associated with the change in recent naphtha exposure (P = .009). The effect of the naphtha exposure during 1 workweek was assessed among 17 workers who provided urine samples Monday preshift, Monday postshift, and Friday postshift. No associations were found. The results of this study do not provide strong evidence of naphtha-associated renal effects at these levels of exposure.

A description is given of the problems of estimating the biological hazards to man resulting from exposure to small doses of ionizing radiation. Unequivocal evidence for harmful effects has generally involved high absorbed doses: our main difficulty is to know how to extrapolate from high to low doses. Extrapolation calls for a theory that can furnish dose‐response relations, and allow for the influence of known modifying factors such as dose‐rate, dose‐frac‐tionation and radiation quality. Relevant experimental evidence for the mutational and life‐shortening effects of radiation on mice is reviewed. Epidemiological evidence for the effects of radiation on U.S. radiologists is used, in conjunction with theory, to assess the consequences of the maximum permissible occupational level, which is currently 5 rem/year. Over the age‐range 35–79 years, overall mortality‐rates might be expected to increase by a factor of about 1–02 over those in an unexposed population. This estimated increase of 2% could well be ...

The frequencies of HLA antigens in 27 patients with silicosis were compared with those of referents matched for exposure to silica dust, age, and sex, and having no roentgenographic signs of silicosis. A group of 900 blood donors served as an additional reference group. The prevalence of HLA-Aw19 was higher in the silicosis patients (29.6 percent) than in the silica-exposed referents (3.7 percent; p = 0.02). In turn, the frequency of Aw19 in the unexposed population consisting of blood donors (19.6 percent) was higher than that of silica-exposed referents (p = 0.04). Accepting that the prevalences of HLA antigens in the blood donors fairly well describe those of the silica-exposed population, the highest risk of developing advanced fibrosis was associated with the phenotypic combination Aw19,B18 (observed-expected ratio = 17.05; p less than 0.01). The results suggest that HLA-Aw19 and the haplotype Aw19,B18 are, at least in Finnish population, associated with a progression into advanced silicotic fibrosis.

The odds ratio from a case-control study of the "cumulative-incidence" type can be used as an estimate of the relative risk of a disease attributable to exposure to an agent only when the incidence of the disease is low. The odds ratio can be modified to obtain an accurate estimate of the relative risk, regardless of the incidence of the disease. This modification of the odds ratio can be performed with any one of four types of auxiliary information: overall probability of disease, probability of disease in the unexposed population, probability of disease in the exposed population, or overall probability of exposure. For "incidence density" case-control studies, the odds ratio equals the relative risk when the estimate of exposure in the comparison group can be considered to be an estimate of the overall probability of exposure in the population at risk. Under certain conditions, such "case-exposure" studies may be preferable to cohort studies and to cumulative-incidence case-control studies. The authors present an approach to hypothesis testing for crude and stratified data from a case-exposure study.

It is of interest whether pleural calcification is primarily the result of long years of exposure to asbestos dust or whether there are factors other than exposure to dust. We have investigated persons working for a long period in a plant processing asbestos products (chrysotile), persons without occupational exposure to dust but living in the vicinity of the plant, and consanguineous relations of patients with pleural calcifications. We have also studied a large population above the age of 40, in the district in which the plant is situated. Comparison of the groups disclosed that prevalence of pleural calcifications was closely related to opportunity for exposure to asbestos dust either occupationally or by family or neighborhood contact, as contrasted with the unexposed population. The prevalence in the group with direct or indirect asbestos exposure was 5.3, 5.8, 3.5%; whereas in the unexposed population it was 0.34%. These results indicate that asbestos is primarily responsible for pleural findings, but that some pleural disease may be the result of the other factors, still not known. The identification of other causes is hampered by the long period which need elapse from the onset of the process to the radiological appearance of the pleural change.

Background: Gastrointestinal infections cause significant health problems, including those affecting the immune, musculoskeletal, and nervous system, and are one of the leading causes for death worldwide. Recent findings suggest that microbiota of the gastrointestinal tract contribute to dementia. Objective: In this nested case-control study we investigated the role of common gastrointestinal infections on the subsequent risk of dementia. Methods: We used a longitudinal sample of 202,806 individuals from health claims data of the largest German health insurer and applied a nested case-control design with 23,354 initial dementia cases between 2006 and 2014 and 23,354 matched controls. We used conditional logistic regression to compute odds ratios (ORs) for dementia and corresponding 95%confidence intervals (CIs), adjusting for potential confounders. Results: The risk of dementia was increased in patients with recurring incidences of quarters with diagnosed gastrointestinal infections when compared to the unexposed population (one quarter: OR = 1.49, 95%CI = 1.40–1.58; two quarters: OR = 1.70, 95%CI = 1.51–1.91; three or more quarters: OR = 1.64, 95%CI = 1.40–1.93), adjusted for potential confounders. Conclusion: Our findings suggest that recurring gastrointestinal infections are associated with an increased risk of subsequent dementia.

To the Editor.— The description by Gilbert Bogen, MD, of "Symptoms in Vietnam Veterans Exposed to Agent Orange" (242:2391, 1979) may be misleading to Vietnam-era veterans and their physicians. Bogen does not describe how his patient population was selected; the degree of exposure claimed by this population to Agent Orange; any documentation (eg, by assay of herbicide levels in fat biopsy specimens) of the exposure to Agent Orange or its systemic absorption and storage; and any comparison of the reported symptoms between the exposed veterans and an age-matched but unexposed population. His report, without reference to a control population, lists the occurrence of several minor and a few more serious mental and physiological symptoms, including a large number of neuropsychiatric and gastrointestinal complaints. These types of problems are not uncommon in young men who seek medical attention for nonspecific and ill-defined complaints. In the patient population described by Bogen, such