Particulate matter phagocytosis induces tissue factor in differentiating macrophages

Airborne exposure to particulate matter with diameter < 10 mcM (PM10) has been linked to an increased risk of thromboembolic events, but the mechanisms are not completely understood. The aim of this study was to evaluate the effect of PM10 phagocytosis on the release of procoagulant molecules in human differentiating macrophages, and that of PM10 inhalation in an experimental model in rats. Human monocytes were separated from the peripheral blood by the lymphoprep method, differentiated in vitro and treated with standard PM10 or vehicle. Sprague-Dawley rats were instilled intratracheally with PM10 or vehicle alone. The outcome was expression of proinflammatory genes and of tissue factor (TF). In human differentiating macrophages, PM10 exposure upregulated inflammatory genes, but most consistently induced TF mRNA and protein levels, but not TF protein inhibitor, resulting in increased TF membrane expression and a procoagulant phenotype. Differentiation towards the anti-inflammatory M2 phenotype inhibited PM10 -mediated TF expression. TF induction required phagocytosis of PM10 , whereas phagocytosis of inert particles was less effective. PM10 phagocytosis was associated with a gene expression profile consistent with intracellular retention of iron, inducing oxidative stress. Both PM10 and iron activated the stress kinases ERK1/2 pathway, involved in the induction of TF expression. In rats, alveolar exposure to PM10 was associated with pulmonary recruitment of inflammatory cells and resulted in local, but not systemic, induction of TF expression, which was sufficient to increase circulating TF levels. In conclusion, TF induction by differentiating lung macrophages, activated following phagocytosis, contributes to the increased risk of thromboembolic complications associated with PM10 exposure.

Extracellular histones mediate the effects of metal-rich air particles on blood coagulation

BACKGROUND

Epidemiological studies have shown associations of particulate matter (PM) exposure with hypercoagulability and thrombosis. Extracellular circulating histones have recently been identified as novel mediators of inflammatory and procoagulant responses. The potential roles of extracellular histones in PM-related hypercoagulability have yet not been investigated.

OBJECTIVES

In 63 steel workers, we evaluated the effects of exposure to PM and PM metal components on two extracellular histone modifications (H3K4me3 and H3K9ac); and the association of H3K4me3 and H3K9ac with coagulation markers.

METHODS

Extracellular H3K4me3 and H3K9ac were determined in plasma through enzyme-linked immunosorbent assays. Coagulation markers included endogenous thrombin potentials (ETPs), tissue-type plasminogen activator antigen (t-PA) and D-dimer. Exposure to PM with aerodynamic diameters <1 μm (PM1) or <10 μm (PM10) and PM10 metal components were estimated for each participant.

RESULTS

The coagulation marker ETP, measured in the presence of soluble thrombomodulin (ETP TM+), showed significant positive associations with PM1 (β=107.84, p=0.03), PM10 (β=83.06, p=0.02), and zinc (β=75.14, p=0.03); and a marginal association with iron (β=122.58, p=0.07). Additional PM effects were observed on t-PA, D-dimer, and ETP TM+. PM1 exposure was associated with increased plasma H3K4me3 and H3K9ac (β=0.20, p=0.02; β=0.16, p=0.05, respectively). H3K4me3, but not H3K9ac, was associated with zinc (β=0.13, p=0.03) and iron (β=0.32, p=0.01) contained in PM. ETP TM+ was increased in association with higher plasma H3K4me3 (β=0.50, p=0.05) and H3K9ac (β=0.54, p=0.05).

CONCLUSIONS

This observational study suggests potential roles of extracellular histones in PM-induced hypercoagulability. Experimental studies are warranted to further characterize these findings.

Update of the mortality study of workers exposed to polychlorinated biphenyls (Pcbs) in two Italian capacitor manufacturing plants

BACKGROUND

PCB carcinogenicity to humans is still controversial. Cohort mortality studies in PCB-exposed workers reported elevated risks for the following causes of death: liver, stomach, digestive, brain, prostate cancers and non-Hodgkin lymphoma.

OBJECTIVES

The purpose of this study was to update as of December 2006 the mortality experience of two Italian cohorts of workers employed in the manufacture of capacitors impregnated with PCBs.

METHODS

Age-gender-and calendar period adjusted Standardized Mortality Ratios (SMRs) and 95% Confidence Intervals (CI) were calculated using regional rates. Analyses by duration of employment and time since first employment were performed Results: Vital status was ascertained for 98.9% of the study subjects. Mortality from biliary tract cancer among males (SMR 3.91; 95%CI 1.47-10.41), digestive cancer "not otherwise specified" in the whole cohort (SMR 2.54; 95%CI 1.21-5.34), and brain cancer in Plant I (SMR 2.13; 95%CI 1.02-4.48), were significantly increased. Increased risks were also observed for Hodgkin's and non-Hodgkin lymphoma. No linear associations between mortality and duration of employment or latency were observed for these cancers. Mortality from stomach cancer did not differ from expectation in the whole cohort, however an increasing risk with increasing duration of employment was detected (p for trend=0.02).

CONCLUSIONS

The current update suggests possibly increased cancer risks in PCB-exposed workers, affecting in particular the digestive system, brain, and lymphohemopoietic tissue. However the limited sample size, the lack of clear trends with duration of employment or with latency period, preclude to derive definite conclusions about PCB exposure and the increased cancer risks.

Epigenetics and pesticides

Pesticides, a wide class of environmental contaminants, may cause both acute and delayed health effects in exposed subjects. These effects can range from simple irritation of the skin and eyes to more severe effects such as affecting the nervous system, the reproductive system and cancer. The molecular mechanisms underlying such effects are still under investigation. Epigenetics is the study of heritable changes in gene expression that occur without a change in the DNA sequence. Several epigenetic mechanisms, including DNA methylation, histone modifications and microRNA expression, can be triggered by environmental factors. We review current evidences indicating that epigenetic modifications may mediate pesticide effects on human health. In vitro, animal, and human investigations have identified several classes of pesticides that modify epigenetic marks, including endocrine disruptors, persistent organic pollutants, arsenic, several herbicides and insecticides. Several investigations have examined the effects of environmental exposures and epigenetic markers, and identified toxicants that modify epigenetic states. These modifications are similar to the ones found in pathological tissue samples. In spite of the current limitations, available evidence supports the concept that epigenetics holds substantial potential for furthering our understanding of the molecular mechanisms of pesticides health effects, as well as for predicting health-related risks due to conditions of environmental exposure and individual susceptibility.

The contribution of Enrico C. Vigliani (1907-1992) to the international development of occupational medicine and industrial hygiene

BACKGROUND

One of the last century's greatest personalities in Occupational Medicine was Enrico Carlo Vigliani (1907-1992), director of the "Clinica del Lavoro" in Milan (1942-1977), editor-in-chief of "La Medicina del Lavoro" (1942-1991), Secretary-Treasurer and then President of the "Permanent Commission and International Association on Occupational Health" (1957-1981), the original nucleus of the ICOH.

OBJECTIVES

The 20th anniversary of his death provides us with the opportunity to discuss the role of this brilliant scholar in the international development of Occupational Medicine and Industrial Hygiene.

METHODS

A comprehensive analysis of Vigliani's scientific works was conducted. In addition, his close collaborators and pupils were interviewed.

RESULTS

In the 1930s, as a young doctor, Vigliani, first in the world, demonstrated the effect of lead on porphyrin metabolism. Afterwards he conducted pioneering studies on occupational oncology (benzene-induced leukaemia, bladder cancer due to aromatic amines, asbestos-related tumours), pathogenesis of silicosis, encephalopathy in carbon disulfide poisoning, byssinosis and metal fume fever, so influencing international research and the implementation of preventive measures against these conditions. Vigliani's scientific authority was widely recognized internationally, as confirmed by his role in ICOH. During his period of active service, the Commission developed from an academic institution to a more open association, substantially increasing its membership. Furthermore, he contributed to establishing subcommittees devoted to specific topics (now called "scientific committees"), one of the strengths of the present Commission.

CONCLUSIONS

Vigliani's contribution to the development of Occupational Health may be considered as an expression of his genial eclecticism which ranged from clinical medicine to the environment.

Environmental and biological monitoring of PAHs exposure in coke-oven workers at the Taranto plant compared to two groups from the general population of Apulia, Italy

BACKGROUND

Polycyclic aromatic hydrocarbons (PAHs) exposure in the coke industry poses a risk for workers' health as well as for subjects living in the plant vicinity.

OBJECTIVES

To assess PAHs exposure in coke-oven workers (CW) at the Taranto plant, Apulia, and in subjects from the general population living near (NC) and far away (FC) from the plant.

METHODS

Exposure was assessed by personal air sampling and urinary 1-hydroxypyrene (1-OHP) measured in 100 CW 18 NC and 15 FC.

RESULTS

Median airborne benzo[a]pyrene (BaP) levels were 152, 1.5, and 3.6 ng/m3 in CW NC, and FC, respectively. In CW, median 1-OHP increased from 1.45 to 1.96 microg/g creatinine (crt) during the work shift (p > 0.05); in NC and FC, 1-OHP levels were 0.56 and 0.53 microg/g crt. No significant differences between NC and FC for both air and urinary indices were found. BaP exposure in CW exceeded the recently proposed German acceptable (70 ng/m3) and tolerable (700 ng/m3) risk-based limit values in 82 and 11% of subjects, respectively. In NC and FC, BaP exposure exceeded the European target value for ambient air (1 ng/m3) in 67 and 60% of subjects, respectively. Biomonitoring showed that 21% of CW had 1-OHP levels higher than the proposed biological limit value for the coke-oven industry (4.4 microg/g crt), while 93% of FC, and 88% of NC, had 1-OHP levels exceeding the Italian reference value (0.3 microg/g crt). Among non-smokers, a linear regression between 1-OHP and BaP (Pearson value r = 0.65, p < 0.05) allowed us to estimate levels of 1.2 and 1.9 microg/g crt for 1-OHP end-of-shift corresponding to acceptable and tolerable limit values.

CONCLUSIONS

Although lower than in the past, PAHs exposure in the coke plant still poses a health risk for workers and the general population and requires further efforts to improve workplace conditions.

[Hazard identification and risk evaluation in the metal industry: the epigenetic challenge]

The contribution of scientific knowledge to workplace health and safety measures is becoming more and more relevant. To identify hazards, an increasing number of mechanistic markers (of exposure, of effect, of individual susceptibility) are now available. To be effective, prevention measures should take into consideration not just the hazards, but also the risk which may vary among different populations and across individuals exposed to the same hazard. A new, extremely promising class of molecular markers of gene-environment interaction comes from epigenetics research (e.g., DNA methylation, histone modification, mi-RNA). A recent epigenetic epidemiology study in workers exposed to metals and PM in the metal industry disclosed their potential role as predictor of extremely early effects on gene expression regulating inflammation and blood coagulation function. A possible, worrisome development in applying mechanistic knowledge in exposure monitoring and exposed individuals' surveillance is to divert the attention from the control of exposure and put the focus on the screening of susceptible individuals only. This raises ethical, social and legal issues which may ultimately impact throughout the practice of occupational and environmental health.

[Air and biomonitoring of occupational exposure to anesthetic gases in the health care workers of a large hospital in Milan]

In this study exposure to anesthetic gases in health care workers of a hospital of Milan was investigated. The evaluation focused on the period 2007-2010 and was performed by environmental monitoring (20 operating rooms and 54 samples) and biological monitoring (180 workers and 242 urine samples). Mean airborne exposure was 3:15 and 0.34 ppm for nitrogen protoxide (N2O) and sevorane; in end-of-exposure urine samples the concentration of N2O and hexafluoroisopropanol, metabolite of sevorane, were 4.85 mg/L and 0.21 mg/L, with 80 and 21% of values below the quantification limit. Sevorane monitoring exceeded or equaled the environmental limit value of 0.5 ppm and the biological exposure index in 17 and 11% of measures. There were no observed exceedances of the limit for N2O. The anesthetist and scrub nurse were tasks with greater exposure. There was a significant correlation between airborne halogenated gases and urinary hexafluoroisopropanol. The results of this study indicates that further efforts are needed to improve the hygienic conditions in the investigated hospital.

Plasma levels of dioxins, furans, non-ortho-PCBs, and TEQs in the Seveso population 17 years after the accident

BACKGROUND

The Seveso accident (Italy) in 1976 caused the contamination of a large population by 2,3,7,8-tetrachlorodibenzo-para-dioxin (2,3, 7,8-TCDD). The contaminated territory was divided into three zones: A (very high contamination), B (high contamination), and R (low contamination). We report here the plasma concentrations of seven polychlorinated dibenzo-para-dioxins (PCDDs), 10 polychlorinated dibenzofurans (PCDFs), four non-ortho-polychlorinated biphenyls PCBs (nPCBs), and Toxic Equivalencies (TEQs) in a sample of residents in the most polluted zones A and B and in a reference non-contaminated zone.

METHODS

From December 1992 to March 1994, 62 individuals were randomly selected from the population living in zone A (No. =7) and B (No. =55). A sample of 59 subjects living in a surrounding non-contaminated area (non-ABR), frequency-matched by gender, age, and smoking history, was used as reference. All subjects were administered a questionnaire surveying demographic, lifestyle, medical history, and accident-related factors. We assayed plasma PCDD, PCDF, and nPCB concentrations by high-resolution gas chromatography/high resolution mass spectrometric (HRGC/HRMS) analysis, with results reported as pg/g of lipid, or parts per trillion (ppt). We calculated TEQs using the WHO 2005 Toxic Equivalency Factors (TEFs).

RESULTS

We found elevated median levels of 2,3, 7,8-TCDD in plasma samples of subjects living in zone A (73.3 ppt) and zone B (12.4 ppt), compared with residents in the reference zone (5.5 ppt). In analyses adjusted for gender, age, smoking, and body mass index (BMI), none of the other congeners showed levels higher than reference in the contaminated zones. Compared with men, women showed higher levels (113%) of 2,3, 7,8-TCDD and a slight elevation (17%) of TEQ for the other congeners. Age was strongly positively associated with most congener levels; TEQs for PCDDs, PCDFs, and nPCBs showed respectively 12%, 24%, and 41% increases for every 10 years of age. Current smokers had lower (from -37% to -67%) TEQ levels than subjects who had never smoked. BMI was negatively associated with levels of a few congeners, but with no impact on TEQ values.

CONCLUSIONS

The Seveso accident caused a severe exposure of the population to 2,3,7,8-TCDD only. None of the other congeners analyzed showed variation across zones. Age showed a strong positive association with TEQs for all classes of compounds (PCDDs, PCDFs, and nPCBs).

[Vitamin D as a cardiovascular risk factor in workers]

Numerous evidence suggests that vitamin D deficiency is implicated in the development of cardiovascular risk. It has been investigated the relationship between cardiovascular risk factors and vitamin D concentrations in 264 consecutive workers from Centro Obesità e Lavoro della Clinica del Lavoro di Milano. For these studies, glicometaboliche analysis, anthropometric measurements and impedance evalutation were performed and questionnaires to estimate nutrient levels in the diet were administered. The levels of vitamin D are found to be deficient in 166 patients (less than 20 ng/mL), insufficient in 63 patients (less than 30 ng/mL) and optimal for the remaining 35 patients. A significant negative association was observed between the concentrations of vitamin D and cardiovascular risk factors (HOMA ratio and TG/HDL) ratios and BMI. Vitamin D is a cardiovascular risk factor "corrected" for example by changing the eating habits of workers.

[Epigenetic effects as mediators of procoagulant action of thin dust with high metal content. Study on occupational epidemiology]

Blood hypo-methylation mediates the effects of metal-rich airborne particles on blood coagulation: An occupational epidemiological study. Particulate matter (PM) exposure is associated with increased coagulation and thrombosis, but the biological mechanism has not yet been clarified. DNA methylation represents a potential mechanism because it can be modified by environmental factors. Foundry workers are exposed to PM components and showed increased cardiovascular risk. In a group of 63 steel workers we found that PM and zinc airborne levels were negatively associated with leukocyte DNA methylation in genes NOS3 and ET-1 (b = -1.1; p = 0.002 and b = -1.5; p = 0.003, for zinc exposure respectively in multivariate regression models; b = -0.9 with p = 0.01 for PM10 exposure and NOS3) and in turn, DNA hypo-methylation resulted associated with increased Endogenous Thrombin Potential (for NOS3 b = -45.0, p = 0.001; and for ET-1 b = -16.4, p = 0.03). Our study based on healthy subject exposed in occupational setting, suggests that gene specific hypomethylation contributes to environmentally-induced hypercoagulability.

[Environmental and biological monitoring of exposure to PAHs in Taranto coke-oven workers and in two groups of the general population from Apulia]

The exposure to PAHs was assessed by personal air sampling and urinary 1-hydroxypyrene (1-OHP) in 100 coke-oven workers (CW) of the Taranto plant and in subjects from the general population living close (NC, 18) and far away (FC, 15) from the plant. Median airborne benzo[a]pyrene (BaP) and 1-OHP levels were 152, 1.5, and 3.6 ng/m3 and 2.0, 0.5 and 0.6 microg/g creatinine in CW, NC, and FC, respectively. BaP exposure exceeded the German acceptable (70 ng/m3) and tolerable (700 ng/m3) limit risk based values in 82 and 11% of CW and the European target value for ambient air (1 ng/m3) in about 65% of NC and FC. 1-OHP levels exceed the proposed biological limit value for the coke-oven industry (4.4 microg/g crt) in 21% of CW and the Italian reference value (0.3 microg/g crt) in about 90% of NC and FC. The exposure resulted lower than in the past, but this study highlights that PAHs exposure from the coke plant still poses a health risk for workers and the general population.

[The assessment of risk for xylene exposure in a laboratory of anatomy: comparison between computational models and environmental and biological monitoring]

Exposure to xylene in a pathology laboratory was evaluated using two algorithms: Stoffenmanager and Archi.me.de. The results were compared with those obtained by applying the environmental and biological monitoring of the exposure. The use of models required a period of self-learning and, for Stoffenmanager, knowledge of the English language. Information on the toxicity and safety of xylene, available from the medial and safety data sheets, and the conditions and amount of use, obtained through a survey and interviews with operators, have been imputed. Stoffenmanager estimated low the inhalation exposure and medium the dermal exposure, with a value of personal exposure during the work shift of 1.4 mg/m3. A.r.chi.me.d.e. estimated negligible the risk to health. These ratings are consistent with those obtained using the experimental approach. This result, combined with the simplicity and low cost, makes the algorithms very interesting tools for the assessment of chemical risk in the workplace.

[Evaluation of the work-related disability in people affected by Ehlers-Danlos syndrome]

The Ehlers-Danlos syndrome (EDS), inherited disorder of connective tissue, frequently leads to impairment of various functional areas, including employment. In 35 subjects with classic type EDS, 14 hypermobile, 3 vascular was administered 7 visual analogical scales (pain, stiffness, activities of daily living, instrumental activities of daily living, work, social relations). An impairment of particular significance in total score and in individual areas emerges is in the hypermobile group, followed by classic, less for the vasculature. Overall there is a significant alteration of the quality of life that deserves proper evaluation to facilitate the definition of fitness and the improvement of job insertion in patients with EDS.

[Identification of biomarkers of short- and medium-term exposure in urine and hair of subjects exposed to terbuthylazine]

Terbuthylazine (TBA) is a herbicide widely used for weed control in corn crop. In mammals it is completely metabolized and excreted in urine, mostly as desetilterbutilazina (DET). This work aims to evaluate the use of urine and hair as matrices for monitoring short- and medium-term exposure to TBA. Levels of TBA and DET have been evaluated in hair and urine samples of 12 exposed farmers, 14 rural residents, 17 urban residents. In hair TBA was quantified in all samples of farmers and rural residents, but not of urban residents. In urine DET was detected in post-application samples of farmers but not in rural and urban residents. These results suggest that TBA in hair can be used as an index of cumulative exposure to TBA, while DET in the urine can be used as an index of short-term exposure in farmers.

[Prevalence of obstructive sleep apnea syndrome in a group of obese workers]

The Obstructive Sleep Apnea Syndrome (OSAS) is a quite diffused in workers disease, mainly in obese or overweight subjects. This syndrome can cause cardiovascular and cerebral complications and have negative effects on job performances. We evaluated 214 obese/overweight workers referred from different job areas. A diagnosis of OSAS was pre-existent in about 5% of the examined subjects, and clinical elements suggesting suspect of OSAS were present in about 15% of the sample. The risk of development Obstructive Sleep Apnea Syndrome seems to be linear correlated with BMI, neck and waist circumference. We did not find any correlation between OSAS risk and job area. We strongly suggest that health surveillance should include the evaluation of the possible presence of sleep disorders to reduce the risks associated and the negative consequences on job performances.

[Comparison of indexes for assessing insulin resistance for the health surveillance among workers]

Night shift workers present a high risk to develop metabolic and cardiovascular disorders for alterations that involve effects on circadian rhythms at the level of insulin resistance (IR). Monitor such parameter in this category of workers, therefore, is a crucial step in health surveillance. To this aim, the currently in use test consists in the calculation of the HOMA index [basal insulin (MU/ml) x basal glycemy(mmol/l)/22.5], a measurement with a considerable cost (about 13 Euros). Recent studies demonstrated that the measurement of TyG index calculated as Ln[Triglycerids (mg/dl) x Glucose(mg/dl)/2] and of the triglycerids/HDL-cholesterol ratio correlates with HOMA index. These analyses cost altogether about 5 Euros, allowing a clear decrease of expenses. Our study, carried out on 217 workers at Centre for Obesity and Occupational Medicine of the Occupational Medicine Clinic of Milan, confirmed such correlation and identified the TyG as the index with the best cost/performance ratio. Our future goal is to establish cut-off values, necessary to adopt the TyG as first choice index.

[Applicability of the test SIO on obesity-related disability (TSD-OC) in occupational medicine for the evaluation of work problems linked to overweight-obesity condition]

Obesity is frequently associated with functional changes that may affect work capacity, so we administered to a group of 198 overweight-obese subjects with median BMI of 32.7 and median waist circumference of 101 cm, the test-TSD OC which consists of 7 sections (pain, stiffness, activities of daily life, activities of the house, instrumental activities of daily living, work, social relations) for a total of 36 visual analogical scales. After the identification of 4 workers categories (health, services, administration, commerce/industry), resulted homogeneous for age, BMI, CV, we saw that the work section was more compromised for health and services. The overall disability increases especially in relation to BMI and seems influenced by age and sex.

Global DNA methylation and low-level exposure to benzene

INTRODUCTION

Global genomic hypomethylation is a common event in cancer tissues that is frequently observed in hematopoietic malignancies, including leukemia. Benzene, an established leukemogen at high doses, has been suggested to induce hypomethylation based on investigations of DNA methylation in LINE-1 and Alu repetitive elements. Whether global genomic DNA methylation content is reduced in response to benzene exposure is still undetermined.

METHODS

We measured global DNA methylation in 78 gasoline station attendants and 58 controls in peripheral blood cells using high-resolution gas chromatography-mass spectrometry. PCR-Pyrosequencing measures of DNA methylation at Alu and LINE-1 repetitive elements, representing a large proportion of methylation in non-coding regions, were also available. Exposure markers included personal airborne benzene, and urinary benzene, t,t-muconic acid (t,t-MA) and S-phelylmercapturic acid.

RESULTS

Mean global DNA methylation was 5.474 (+/- 0.083) %5mC in controls and 5.409 (+/- 0.142) %5mC in exposed participants (p = 0.01). All methylation markers were negatively correlated with airborne benzene. Alu and LINE-1 methylation, but not global DNA methylation, were negatively associated with t,t-MA; no association with the other urinary biomarkers was found. Multiple linear regression analysis adjusted for gender and age confirmed the results of correlation analysis and showed a 1.6% decrease in global DNA methylation associated with being gasoline station attendants. Alu and LINE-1 methylation levels were not associated with global DNA methylation.

CONCLUSION

Our results show that benzene exposure is associated with alterations in both global DNA and repetitive element methylation. Global and repetitive element methylation levels are not correlated in blood DNA, likely representing independent responses to benzene exposure.

[Assessment of exposure to polycyclic aromatic hydrocarbons in asphalt workers by measurement of urinary 1-hydroxypyrene]

INTRODUCTION

Asphalt workers are potentially exposed to polycyclic aromatic hydrocarbons (PAHs). As some PAHs are classified as carcinogenic, the assessment of occupational exposure to these agents is of the utmost importance in preventing toxic effects.

OBJECTIVES

To assess exposure to PAHs by urinary 1-hydroxypyrene (1-OHPyr).

METHODS

We studied 22 asphalt workers (14 smokers) and 5 control subjects (1 smoker). Multiple samples of urine (up to 4per subject) were collected at the end of the shift for the measurement of 1-OHPyr by LCMS/MS. Univariate and multivariate linear models for repeated measurements were used to evaluate the differences between groups and to identify the variables influencing of exposure.

RESULTS

The median urinary excretion of 1-OHPyr in asphalt workers was low, but higher than that of control subjects (184 vs. <20 ng/L, or 106 vs. <20 ng/g creatinine, p < 0.001); cigarette smoking marginally increased 1-OHPyr in smoking asphalt workers in comparison to non-smokers (129 vs. 208 ng/L p= 0.09 or 94 vs. 121 ng/g creatinine, p = 0.06). The number of consecutive days at work significantly influenced the urinary excretion of l-OHPyr [+59% every day, CI: (2, 147), p = 0.04]. Subjects using paving machines had the highest exposure. A strong association between 1-OHPyr and urinary creatinine was observed.

CONCLUSIONS

urinary 1-OHPyr is a useful indicator of occupational exposure to low levels of PAHs, such as those found in the subjects studied; in using this biomarker it is recommended to collect urine samples at the end of the working week and to express levels of the biomarker corrected for urinary creatinine.

DNA methylation in repetitive elements and Alzheimer disease

Epigenetics is believed to play a role in Alzheimer's disease (AD). DNA methylation, the most investigated epigenetic hallmark, is a reversible mechanism that modifies genome function and chromosomal stability through the addition of methyl groups to cytosine located in CpG dinucleotides to form 5 methylcytosine (5mC). Methylation status of repetitive elements (i.e. Alu, LINE-1 and SAT-α) is a major contributor of global DNA methylation patterns and has been investigated in relation to a variety of human diseases. However, the role of methylation of repetitive elements in blood of AD patients has never been investigated so far. In the present study, a quantitative bisulfite-PCR pyrosequencing method was used to evaluate methylation of Alu, LINE-1 and SAT-α sequences in 43 AD patients and 38 healthy donors. In multivariate analysis adjusting for age and gender, LINE-1 was increased in AD patients compared with healthy volunteers (ADs: 83.6%5mC, volunteers: 83.1%5mC, p-value: 0.05). The group with best performances in mini mental state examination (MMSE) showed higher levels of LINE-1 methylation compared to the group with worst performances (MMSE>22: 83.9%5mC; MMSE≤22: 83.2%5mC; p=0.05). Our data suggest that LINE-1 methylation may lead to a better understanding of AD pathogenesis and course, and may contribute to identify novel markers useful to assess risk stratification. Further prospective investigations are warranted to evaluate the dynamics of DNA methylation from early-stage AD to advanced phases of the disease.

[Incidence of malignant mesothelioma and asbestos exposure in the Lombardy region, Italy, 2000-2008]

We evaluated the trend of incidence and asbestos exposure of malignant mesothelioma (MM) in 2000-2008 in the Lombardy Region (Italy). We recorded 2,816 MMs (1,793 men, 1,023 women). The age-standardized rates (x 100,000/year) were 3.4 (men) and 1.4 (women) (standard population: Europe). We found a 3.0% and 0.9% increase per year of number of cases and rate, respectively. Exposure was obtained in 2,671 cases (94.9%). Occupational exposure to asbestos was found for 1,296 (72.3%) men and 377 (36.9%) women, non-occupational exposure in 141 (13.8%) women and 58 (3.2%) men. The exposure profile within gender did not vary over years.

[Permanent education, updating and accreditation in occupational medicine: the contribution of the Italian Society of Occupational Medicine and Industrial Hygiene (SIMLII) in the first decade of the 21st century]

BACKGROUND

Permanent education of health workers is obligatory under Italian legislation and is managed by the Ministry of Health through its Permanent Education Programme.

METHODS

In 2000 the Italian Society of Occupational Medicine and Industrial Hygiene (SIMLII), set up and implemented a programme of Permanent Education and Accreditation for specialists in occupational medicine, based on participation in "non-mandatory" and "mandatory" educational activities. "Non-mandatory" activities were chosen by the individual physician for education in topics related to occupational medicine. "Mandatory" educational activities, which were organised by the Society, included in-depth analysis of the Society's guidelines related to specific topics in occupational medicine.

RESULTS AND DISCUSSION

The Guidelines study course played a pre-eminent role in the Society's permanent education programme and was greatly appreciated by all participants. The Board of the Society has recently approved a new Plan of Permanent Education, identifying the means (Guidelines, Consensus Documents) whereby occupational physicians can improve their professional standards. The Plan's aims are to facilitate accreditation and also to identify and promote high-quality updating programmes which will lead to recognition of 'professional excellence". Crucial to its success will be a 3-year on-line learning programme (MeLA) that SIMLII has just implemented, which will enable occupational physicians to acquire credits in "Occupational Medicine and Workplace Safety", as required by current Italian legislation. This article summarizes SIMLII activities over the past ten years in the field of permanent medical education for occupational physicians.

Impact of ambient air pollution on birth outcomes: systematic review of the current evidences

BACKGROUND

There is growing interest in the possible association between maternal exposure to air pollutants and reproductive outcomes, particularly birth weight and gestational duration. Four systematic reviews of data were published in 2004-2005, but the wide variability of methods and results among the different studies produced conflicting conclusions. This study was done to establish whether recent literature has provided more conclusive evidence regarding a link between air pollutants and birth outcomes.

METHODS

We reviewed 18 original epidemiological studies on maternal exposure to particulate matter (PM), NO2, CO and O3, and outcomes of preterm delivery or low birth weight published since 2004.

RESULTS

Large variability across studies in design, precision in maternal georeferentiation, methods in exposure assessment, and type of pollutant considered, limited the strength of the evidence of adverse affects of ambient air pollution on birth outcomes. Nevertheless, evidence suggests exposure to particulate matter, especially at its finest fraction (PM25), may have the potential to adversely affect birth weight. We further found limited evidence of a possible association between maternal exposure to air pollutants during the first trimester and increased risk of preterm delivery.

DISCUSSION

The observed adverse effects were generally small. However, possible important factors such as maternal activity pattern, diet, smoking and occupation, that are usually not reported on the birth certificate, might have led to exposure misclassification and confounding and could have hidden moderately increased risks. In conclusion, additional studies since 2004 have not been able to conclusively show a definitive correlation between air pollution and adverse birth outcomes; although it appears that small size particulate matter could affect birth weight. Additional well-conducted studies that include detailed information on maternal risk factors and using validated models for estimating maternal exposure are needed to establish the extent of the association between air pollution and birth outcomes.

Effects of inhalable particulate matter on blood coagulation

BACKGROUND

Particulate matter (PM) exposure has been linked to increased risk of cardiovascular disease, possibly resulting from hypercoagulability and thrombosis. Lung and systemic inflammation resulting from PM inhalation may activate blood coagulation, but mechanisms for PM-related hypercoagulability are still largely unknown.

OBJECTIVES

To identify coagulation mechanisms activated by PM in a population with well-characterized exposure.

METHODS

We measured prothrombin time (PT), activated partial thromboplastin time, endogenous thrombin potentials (ETPs) with/without exogenous triggers and with/without soluble thrombomodulin, tissue-type plasminogen activator (t-PA) antigen, D-dimer and C-reactive protein (CRP) in 37 workers in a steel production plant with well-characterized exposure to PM with aerodynamic diameter of < 1 mum (PM(1)) and coarse PM (PM(10) - PM(1)). Blood samples were collected from each subject on the first (baseline) and last (postexposure) day of a 4-day work week. We analyzed differences between baseline and postexposure levels using a paired Student's t-test. We fitted multivariate mixed-regression models to estimate the associations of interquartile range PM(1) and coarse PM exposure with parameter levels.

RESULTS

None of the parameters showed any significant changes from baseline in postexposure samples. However, exposure levels were associated with shorter PT (beta[PM(1)] = -0.33 s, P = 0.08; beta[PM(coarse)] = - 0.33 s, P = 0.01), and higher ETP without exogenous triggers and with thrombomodulin (beta[PM(1)] = + 99 nm min, P = 0.02; beta[PM(coarse)] = + 66 nm min, P = 0.05), t-PA (beta[PM(1)] = + 0.72 ng mL(-1), P = 0.01; beta[PM(coarse)] = + 0.88 ng mL(-1), P = 0.04), and CRP (beta[PM(1)] = + 0.59 mg L(-1), P = 0.03; beta[PM(coarse)] = + 0.48 mg L(-1), P = 0.01).

CONCLUSIONS

PM exposure did not show any short-term effect within the week of the study. The association of PM exposure with PT, ETP and CRP provides some evidence of long-term effects on inflammation and coagulation.

[Work as a basic human need and health promoting factor]

The Italian Constitution (1948) defines 'work' as the founding value of the Italian Republic. This choice was not motivated by mere economic reasons, but rather stemmed from the recognition that work is the most appropriate tool for the expression of the human personality in society, that it is an asset and a right that will increase the dignity of every person, and which corresponds to a fundamental human desire to fulfil oneself in relationship with other persons and the entire world This view of work, including its technical and manual aspects, was unknown to the ancient mentality and became familiar to us through the monastic orders of the early middle ages, which began to conceive and practise human work as a means of participating in the work of creation and transmitted this value over the centuries. As we experience today, if occupation is lacking, a basic condition for the development of the person and for his/her contribution to the growth of society is lost. Given the meaning of work in human experience, it is not surprising that unemployment represents not only a worrisome economic indicator, but also the cause of ill health. At the end of 2009 unemployment in the European Union reached 10%, similar to the rate in the US; in Italy it was estimated at 8.5% in December 2009 and is expected to reach 10% in 2010. In Lombardy, although employment had been constantly increasing between 1995 and 2008, and the current unemployment rate is as low as 4.9%, 100,000 jobs were lost in 2009. Several scientific papers have demonstrated the association between lack of occupation and lack of physical and mental health. In the present period of crisis, increases of 30% in cases of anxiety syndrome and of 15% in cases of depression have been reported. An increase in suicides among unemployed persons has been documented in several countries even if there are still problems of interpretation of the causal chain of events. Mortality among the unemployed increased, not only that due to violent causes, but also mortality for all causes, cardiovascular diseases and cancer. A survey in the Turin area, Northern Italy, showed a twofold increase in mortality among unemployed men. Women were affected both by husbands' unemployment and by their own unemployment because of the previous increasing rate of female occupation. The worse the occupational condition (from "seeking work" to "temporary employment" down to "unemployed and no longer seeking work") the higher the mortality: in the latter category, where the most evident problem is marginalization and social exclusion, the increase in mortality was fourfold. The role of occupational health physicians is to recognize the possible negative effects of working conditions and at the same time promote a positive approach to work, even in difficult conditions. This makes prevention more effective and promotes health. To be aware of the meaning of work makes work itself more liveable and more productive. This is how health promotion contributes to the wellbeing of the individual and, at the same time, to the development of the economy and society at large.

[Validity of carbohydrate-deficient transferrine (CDT) in assessing chronic abuse of ethyl alcohol in urban public transport workers]

OBJECTIVES

The aim of this study was to verify the ability of some chemical-clinical parameters, with particular emphasis on carbohydrate-deficient transferrin (CDT), in assessing chronic abuse of ethanol in a group of urban public transport workers.

METHODS

In the 512 subjects, public transport tram drivers, all males, who entered the study, information on the intake of alcoholic beverages was collected during the periodical health surveillance controls performed according to Italian legislation (DM88/99). In the study subjects the following clinical-chemical parameters were measured: CDT gamma-glutamyltransferase (GGT), mean corpuscular volume of erythrocytes (MCV), aspartate aminotransferase (AST), alanine aminotransferase (ALT).

RESULTS

The subjects were divided into five groups according to different levels of alcohol intake: non-drinkers, occasional drinkers, moderate drinkers, habitual drinkers and heavy drinkers. The median values of CDT GGT and MCV were higher in drinkers than in non-drinkers, with an increasing trend in proportion to the amount of ethanol ingested. The validity of each parameter in determining chronic abuse of ethyl alcohol was calculated taking as true the statement on alcohol intake made spontaneously by the subject. CDT was confirmed as the parameter with the best sensitivity and specificity: 90% and 98%, respectively, the negative predictive value was 99%, while the positive predictive power was 45%. The combination of CDT with GGT or MCV led to small improvements in the positive predictive ability, which reached 50% for CDT and MCV and 60% for CDT and GGT.

CONCLUSIONS

Our results confirmed that, also in the workplace, CDT is the most important parameter for the diagnosis of chronic abuse of alcohol intake, but also showed that the positivity of this marker cannot be taken as certainty of abuse. The adoption of further diagnostic tools is therefore proposed, such as a specific questionnaire to collect information on alcohol intake, and in case of positive CDT a second-level test with a high specificity.

Early effects of low benzene exposure on blood cell counts in Bulgarian petrochemical workers

OBJECTIVES

Only few studies have examined early hematological effects in human populations exposed to low benzene levels and their findings are controversial. We evaluated hematological outcomes (WBC, neutrophils, lymphocytes, monocytes, eosinophils, basophils, RBC, Hb, HCT MCV, platelets and MPV) in a population of 153 Bulgarian petrochemical workers exposed to benzene (range 0.01-23.9 ppm) and 50 unexposed subjects.

METHODS

Written informed consent was obtained and a self-administered questionnaire used to collect information on current smoking habits, lifestyle, and occupational activities. Exposure assessment was based on personal monitoring sampling the day before phlebotomy. Urinary trans-trans-muconic acid (t,t-MA) was determined at the beginning and end of the work shift. Based on individual airborne benzene measurements, study subjects were categorized in three exposure categories (referents, <1 and > or =1 ppm). Mean values of each hematologic outcomes in each exposure category were compared with the referent group using a multiple linear regression model adjusted for age, gender, current smoking habits and environmental toluene level. The influence of the CYP2E1 (RsaI and DraI) and NQO1 609C>T genetic polymorphisms on differential hematological parameters was also investigated.

RESULTS

No dose-response effect was observed for most of the examined hematological outcomes (WBC, lymphocytes, neutrophils, monocytes, RBC, Hb, HCT, MCV, platelets and MPV). The eosinophil count was inversely related to benzene exposure only among smokers. Conversely, basophils increased with increasing exposure. No effect on benzene hematotoxicity was found for any of the investigated polymorphisms.

CONCLUSION

In our study we did not find a decline in WBC and lymphocytes related to benzene exposure. A myeloproliferative effect of benzene is highly unlikely to explain the observed reduction in eosinophils and increase in basophils as it would lead to a concordant depression in all granulocyte subpopulations. Whether benzene effects at low doses are present in Caucasian populations remains uncertain, thus warranting further investigations.

[The ISPESL-SIMLII surveys to develop and address updating and accreditation's projects in occupational medicine]

The SIMLII set up a program of continuous training and accreditation of postgraduate specialists in Occupational Health in 2000, before continuous medical training (ECM) was formally introduced. Therefore, especially over the past few years, SIMLII has involved its membership to an ever increasing extent, in an attempt to understand their expectation as regards the scientific community and as regards a continuously evolving discipline that is subject to continuous changes in educational requirements. The surveys carried out by the National Institute of Occupational Safety and Prevention (ISPESL), in collaboration with SIMLII, provided data that, besides identifying the type of activity of the membership, attempted to assess members' compliance with the society's initiatives, with special reference to the Programme for continuous training and accreditation of postgraduates in Occupational Health and the issue of Guidelines.

[Occupational medicine faces new health challenges: the example of alcohol dependence]

The regulations for application of the legislation on control of alcohol consumption at the work place, which were published in the Gazzetta Ufficiale No. 75, March 30, 2006, set the occupational physician a more challenging task, in addition to regular activities related to the prevention of the usual work-related risk factors. The aim of the legislation, which was derived from and inspired by the European Alcohol Action Plan 2000-2005, drawn up by the European Office of the WHO, is to prevent alcohol abuse and its consequences, i.e. accidents and injuries to third parties, and to permit subjects with alcohol dependence to go on working. In this context, occupational physicians are asked to contribute to the early identification of subjects prone to alcohol abuse and assess whether alcohol-dependent subjects can return to work in conditions of safety for themselves and for other workers. Various problems arise for the achievement of these aims in practice, and concern confidentiality, ethical aspects, i.e. use of alcohol screening at hiring, integration of such tests with those used for monitoring conventional occupational exposures, interactions with exposures to other chemical products, just to mention the major issues. Due to these difficulties in the application of the new regulations, field trials become all the more important, since they offer the possibility of assessing efficacy and efficiency of the different approaches.

Effects of exposure to air pollution on blood coagulation

BACKGROUND

Consistent evidence has indicated that air pollution increases the risk of cardiovascular diseases. The underlying mechanisms linking air pollutants to increased cardiovascular risk are unclear.

OBJECTIVES

We investigated the association between the pollution levels and changes in such global coagulation tests as the prothrombin time (PT) and the activated partial thromboplastin time (APTT) in 1218 normal subjects from the Lombardia Region, Italy. Plasma fibrinogen and naturally occurring anticoagulant proteins were also evaluated.

METHODS

Hourly concentrations of particulate (PM10) and gaseous pollutants (CO, NO2, SO2, and O3) were obtained from 53 monitoring sites covering the study area. Generalized additive models were applied to compute standardized regression coefficients controlled for age, gender, body mass index, smoking, alcohol, hormone use, temperature, day of the year, and long-term trends.

RESULTS

The PT became shorter with higher ambient air concentrations at the time of the study of PM10 (coefficient = -0.06; P < 0.05), CO (coefficient = -0.11; P < 0.001) and NO2 (coefficient =-0.06; P < 0.05). In the 30 days before blood sampling, the PT was also negatively associated with the average PM(10) (coefficient = -0.08; P < 0.05) and NO2 (coefficient = -0.08; P < 0.05). No association was found between the APTT and air pollutant levels. In addition, no consistent relations with air pollution were found for fibrinogen, antithrombin, protein C and protein S.

CONCLUSIONS

This investigation shows that air pollution is associated with changes in the global coagulation function, suggesting a tendency towards hypercoagulability after short-term exposure to air pollution. Whether these changes contribute to trigger cardiovascular events remains to be established.

Effects of exposure to air pollution on blood coagulation

BACKGROUND

Consistent evidence has indicated that air pollution increases the risk of cardiovascular diseases. The underlying mechanisms linking air pollutants to increased cardiovascular risk are unclear.

OBJECTIVES

We investigated the association between the pollution levels and changes in such global coagulation tests as the prothrombin time (PT) and the activated partial thromboplastin time (APTT) in 1218 normal subjects from the Lombardia Region, Italy. Plasma fibrinogen and naturally occurring anticoagulant proteins were also evaluated.

METHODS

Hourly concentrations of particulate (PM10) and gaseous pollutants (CO, NO2, SO2, and O3) were obtained from 53 monitoring sites covering the study area. Generalized additive models were applied to compute standardized regression coefficients controlled for age, gender, body mass index, smoking, alcohol, hormone use, temperature, day of the year, and long-term trends.

RESULTS

The PT became shorter with higher ambient air concentrations at the time of the study of PM10 (coefficient = -0.06; P < 0.05), CO (coefficient = -0.11; P < 0.001) and NO2 (coefficient =-0.06; P < 0.05). In the 30 days before blood sampling, the PT was also negatively associated with the average PM(10) (coefficient = -0.08; P < 0.05) and NO2 (coefficient = -0.08; P < 0.05). No association was found between the APTT and air pollutant levels. In addition, no consistent relations with air pollution were found for fibrinogen, antithrombin, protein C and protein S.

CONCLUSIONS

This investigation shows that air pollution is associated with changes in the global coagulation function, suggesting a tendency towards hypercoagulability after short-term exposure to air pollution. Whether these changes contribute to trigger cardiovascular events remains to be established.

[Mortality study in a cohort of workers employed in a plant producing sulphuric acid ]

BACKGROUND

In 1992, the International Agency for Research on Cancer (IARC) classified sulphuric acid mists as human carcinogen, based primarily on human data showing increased risk for larynx cancer. Uncertainties still exist about other respiratory cancers.

OBJECTIVES

We carried out a historical mortality study among workers ofa plant producing sulphuric acid in Tuscany, Italy.

METHODS

We reconstructed a cohort of 1372 male and 37female workers with at least one year of employment at the plant in the period 1962-97; 46% ofthe workers had previously been working in pyrite mines in the area where rocks have a high silica content. Environmental measurements of sulphuric acid and sulphur dioxide from the 1970's were generally below the TLVs. Mortality was investigated as of August 2000; Standardized Mortality Ratios (SMR) were calculated using Tuscany reference rates.

RESULTS

Overall mortality was below expectation (SMR 77). In labourers, larynx cancer deaths were 4 vs 3.1 expected (SMR 130, 95% CI 35-333), while mortality from lung cancer was below expectation (27/32.8, SMR 82, 95% CI 54-120). An excess of myeloid leukaemia was observed mainly in workers without previous experience in mines (3/0.6, SMR 523, 95% CI 108-1527). Mortality from silicosis, but not from lung cancer, was remarkably high among workers with previous employment in mines.

CONCLUSIONS

Among workers employed in sulphuric acid production, with or without previous experience in mines, we did not observe increased mortality from larynx or lung cancer. The increased mortality from myeloid leukaemia cannot be attributed to any of the exposures documented in the study plant and requires further investigation.

Nurses' health, age and the wish to leave the profession--findings from the European NEXT-Study

BACKGROUND AND OBJECTIVES

In many industrialised countries the number of workers with low health is expected to increase in the nursing profession. This will have implications for occupational health work in health care. The European NEXT-Study (www. next-study. net, funded by EU) investigates working conditions of nurses in ten European countries and provides the opportunity to evaluate the role of health with respect to age and the consideration of leaving nursing.

METHODS

26,263 female registered nurses from Belgium, Germany, Finland, France, England, Italy, Netherlands, Poland and Slovakia were eligible for analysis.

RESULTS

In most countries, older nurses considered leaving the profession more frequently than younger nurses. 'Health' was--next to 'professional opportunities' and 'work organisational factors'--strongly associated with the consideration of leaving nursing. However, more than half of all nurses with low health wanted to remain in the profession. This group reported rather positive psychosocial working conditions--but also the highest fear for unemployment.

CONCLUSIONS

The findings indicate that 'the nurse with low health' is reality in many health care settings. Both positive supporting working conditions but also lack of occupational alternatives and fear of unemployment may contribute to this. Current economic, political and demographic trends implicate that the number of active nurses with low health will increase. Occupational health surveillance will be challenged by this. But NEXT findings implicate that prevention also will have to regard work organisational factors if the aim is to sustain nurses' health and to enable nurses to remain healthy in their profession until retirement age.

[Occupational epidemiology and efficiency evidence]

Occupational medicine is undergoing major changes and the question of "evidence" seems essential at this turning point. We need to update knowledge, adjust methods and verify the efficacy of interventions. If this is not done, the discipline might be reduced to just passive application of legislation with a consequent reduction of occupational medicine's professional and scientific content. Procuring evidence is objectively more difficult in the field of prevention than in the clinical field; however, those difficulties should be addressed and not simply handled in a trite way. In occupational medicine there is special opportunity to combine a "population" approach (tending to reduce exposure of the entire population) with a "high risk" approach where particularly susceptible subjects are identified and treated with targeted interventions. The contribution of epidemiology to the goal of underpinning a renewed occupational health practice with proves of evidence, mainly rests in suggesting methods able to (1) guarantee the validity of the observation of relationships between exposures and effects; (2) put together observations and studies independently conducted on the same issue and produce a combined quantitative evaluation; (3) set up ad hoc studies for evaluating prevention measures in progress. Health surveillance programs represent a particularly fertile soil for evaluation research and evidence accrual, however they are not sufficiently taken into consideration for this purpose, and relevant studies are few. A renewed cooperation involving occupational medicine and health centres is necessary to achieve that goal.

Health status and plasma dioxin levels in chloracne cases 20 years after the Seveso, Italy accident

BACKGROUND

The Seveso, Italy accident of 1976 exposed a large population to 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD or simply dioxin). The accident resulted, mostly among children, in one of the largest ever-reported outbreaks of chloracne, the typical skin disorder due to halogenated-hydrocarbon compounds.

OBJECTIVES

Approximately 20 years after the accident, we conducted an epidemiological study in Seveso to investigate (a) the health status of chloracne cases; (b) TCDD-chloracne exposure-response relationship; and (c) factors modifying TCDD toxicity.

METHODS

From 1993 to 1998, we recruited 101 chloracne cases and 211 controls. Trained interviewers administered a structured questionnaire assessing, among other epidemiological variables, information on an extensive list of diseases. During the interview, individual pigmentary characteristics were determined. We measured plasma TCDD levels using high-resolution gas chromatography/mass spectrometry.

RESULTS

Plasma TCDD was still elevated (> 10 ppt) in 78 (26.6%) of the 293 subjects with adequate plasma samples, particularly in females, in subjects who had eaten home-grown animals, and in individuals with older age, higher body mass index and residence near the accident site. After 20 years, health conditions of chloracne cases were similar to those of controls from the Seveso area. Elevated plasma TCDD was associated with chloracne [odds ratio (OR) = 3.7, 95% confidence interval (CI) 1.6-8.8, adjusted for age, sex and residence]. Chloracne risk was higher in subjects younger than 8 years at the accident (OR = 7.4, 95% CI 1.8-30.3) and, contrary to previous hypotheses, did not increase at puberty onset or in teenage years. Subjects with elevated TCDD levels and light hair colour had higher relative odds of chloracne (OR = 9.2, 95% CI 2.6-32.5).

CONCLUSIONS

Dioxin toxicity in chloracne cases was confined to the acute dermatotoxic effects. Chloracne occurrence appeared related to younger age and light hair colour. Age-related dioxin elimination or dilution must be taken into account in interpreting these results.

[DNA methylation analysis in environmental and occupational cancer research]

The present paper reviews recent laboratory methods and experimental evidence concerning epigenetic biomarkers involved in carcinogenesis mechanisms. We introduce DNA methylation and its role in gene expression control. DNA methylation analysis may allow to identify early changes leading to cancer and other chronic diseases. We describe here strategies for laboratory analyses and their possible applications. We examine results from recent experimental studies suggesting that the effects of certain occupational agents are mediated by alterations in DNA methylation. Planning and conducting investigations on exposed human subjects will allow to verify whether DNA methylation changes identified in animal and in-vitro studies may be used as early-effect and susceptibility biomarkers. DNA methylation analysis has the potential for future applications in risk assessment and prevention programs conducted on subjects exposed to human carcinogens.

Descriptive epidemiology of malignant mesothelioma

BACKGROUND

Malignant mesothelioma (MM) is a rare cancer associated with exposure to asbestos, whose occurrence is increasing in industrialized countries.

OBJECTIVES

Describe and discuss: determinant factors, natural history, epidemic pattern, burden of MM to society at large, where interventions should be directed to change MM occurrence, gaps in knowledge.

METHODS

Review of the literature. Description of MM epidemiological features, with emphasis on risk, prognosis, control measures.

RESULTS

MM may be associated with low level asbestos exposure. Natural fibres other than asbestos possess the same carcinogenic potency. The estimated mean induction period is 25 years, and can be as long as 60 or more years. Survival is poor; current rates of MM in industrialized countries mirror past use of asbestos. In the USA, MM incidence increased steeply from the 1970's, peaked in 2000-2004, then levelled off and is expected to return to background levels by 2055. In the same period, the time-pattern for females was constant. Questions remain unanswered about the contribution of environmental asbestos exposure to MM occurrence. A gender effect has been described. The role of genetic and familial susceptibility is suggested by studies in Turkey. Sv40 has been proposed as co-factor in the asbestos-MM association. Controversy about the different hazards of different asbestos forms is still strong.

CONCLUSIONS

World production of asbestos has been declining dramatically in recent years, however increases have occurred in Asia. The decrease in asbestos use and a ban in several industrialized countries have proved effective in reducing the societal burden of MM.

[New effect biomarkers]

The major research goals for researchers developing biomarkers of effect are the development and validation of biomarkers that permit the prediction of the risk of disease in individuals and groups. One important objective is to prevent human cancer. This article reviews the most recent analytical methodologies, validation studies and field trials together with auditing and quality assessment of the necessary data based on scientific grounds. Consideration is given to new developments in the relatively young field of toxicogenomics, possibly leading to the identification of early changes that may lead to both cancer and non-cancer end points. Although the creation and development of reliable databases integrating information from genomic and proteomic research programmes should offer a contribution to the prediction of risks and prevention of diseases related to chemical exposure, the most promising future application of these technologies lies in the molecular diagnosis of diseases whose nosography will probably be redefined.

[The role of biological monitoring in health and epidemiological surveillance: the epidemiological approach]

A fundamental pre-requisite for the realization of biological monitoring programs for health surveillance is the availability of sufficiently accurate tests and adequate knowledge of the relationship between biomarkers and health effects. In this respect, epidemiology plays an essential role: in conjunction with other disciplines (industrial hygiene, toxicology, occupational medicine), it provides a conceptual and methodological framework for many biological monitoring activities. Compared to biomarkers of dose and effect, susceptibility markers (for example, metabolic polymorphisms), for which we have seen an explosion of research in recent years, need a specific consideration in that they pose (or may pose in a non-remote future) special problems. For different reasons, the use of genetic tests for predictive aims at the individual level should now be avoided; their use should be restricted to the research field for a better understanding of etiopathogenetic mechanisms.

[Intention to leave the nursing profession]

BACKGROUND

The NEXT Study (Nurses' Exit Study) was initiated in 10 European countries in order to shed light on nurses' working conditions and reasons of shortage.

OBJECTIVES

The study objective was to determine organisation and psychosocial conditions that lead to premature departure from the nursing profession.

METHODS

The questionnaire we used took into account aspects such as work history, work demands and organisation, career prospectives and individual resources. This article describes steps related to the construction and validation of the questionnaire and sampling methods. Preliminary results are also reported. Data analysis, performed in relation to the intention to leave the nursing profession, showed the distinctiveness of the situation in Italy compared to other European countries.

RESULTS

Conditions related to intention to leave are multifaceted, but they can be summarized as inadequacy of facilities to support the family needs of staff low level of trust in official structures, together with poor support by colleagues and superiors, work overload, and lack of independence at work--although the latter is foreseen in current legislation--and scant career and development possibilities.

CONCLUSIONS

These results confirm the existence of a difficult situation, although certain legislative changes are aimed at solving these problems.