The role of MicroRNAs as early biomarkers of asbestos-related lung cancer: A systematic review and meta-analysis

BACKGROUND

Asbestos is still the leading cause of occupational cancer mortality worldwide. Asbestos-related lung cancer (LC) and malignant pleural mesothelioma (MPM) prognosis is still poor especially at advanced stage, so early diagnosis biomarkers are needed. MicroRNAs (miRNAs) have been proposed as potential early diagnostic biomarkers of asbestos-related LC and MPM.

AIM

To evaluate the role of miRNAs as diagnostic and prognostic biomarkers of asbestos-related LC and MPM by performing a literature systematic review and meta-analysis.

METHODS

MEDLINE, EMBASE via Ovid, PUBMED and Cochrane library databases were systematically searched up to April 2023 to identify relevant articles. A grey literature search was also conducted using the Google Scholar platform. MeSH and free text terms for 'asbestos', 'occupational exposure', 'lung cancer', 'mesothelioma' and 'miRNAs' were used to search the literature. Our systematic review protocol was registered in the PROSPERO database. Study quality was assessed via the Newcastle-Ottawa Scale.

RESULTS

From the search, 331 articles were retrieved, and, after applying our selection criteria, and exclusion of one study for poor quality, 27 studies were included in the review. Most of the studies were hospital-based case-control, conducted in Europe, and evaluated MPM among men only. MiRNAs expression was measured mainly in plasma or serum. MiR-126, miR-132-3p, and miR-103a-3p were the most promising diagnostic biomarkers for MPM, and we estimated a pooled area under the curve (AUC) of 85 %, 73 %, and 50 %, respectively. In relation to MPM prognosis, miR-197‑3p resulted associated with increased survival time. MiR-126, alone and combined with miR-222, was confirmed associated also to LC diagnosis, together with miR-1254 and miR-574-5p; no miRNA was found associated to LC prognosis.

CONCLUSION

Based on our systematic literature review there is suggestive evidence that the expression of specific miRNAs in the blood serum or plasma are associated with asbestos-related LC and MPM diagnosis and prognosis. Further large longitudinal studies are urgently needed to validate these findings and elucidate the underlying mechanisms given the potential important implications for patients' survival.

Reconstructing historical exposure to asbestos: the validation of 'educated guesses'

BACKGROUND

In both the epidemiological and legal context, the causal attribution of asbestos-related lung diseases requires retrospective exposure assessment (REA).

AIMS

To assess the correlation between the retrospective assessment of occupational and anthropogenic environmental exposure to asbestos and its content in the lung tissue.

METHODS

Based on the available exposure information, a team of occupational physicians retrospectively assessed cumulative exposure to asbestos in 24 subjects who died of asbestos-related diseases. The asbestos lung content was analysed using analytical scanning electron microscope (SEM-EDS). The Log10 asbestos fibre count in the autoptic samples was predicted as a function of the Log10 estimated cumulative exposure using univariate regression analysis.

RESULTS

The median count of asbestos fibres by grams of dry weight (ff/gdw) in the lung tissue was 81 339 (range 0-2 135 849.06); it was 287 144 (range 0-2 135 849.06) among the occupationally exposed, and 29 671 (range 0-116 891) among the subjects who only had anthropogenic environmental and/or household exposure. Amphiboles, and particularly amosite (52%) and crocidolite (43%), were detected in all the study subjects. Chrysotile was not detected in any of the samples. Overall, the retrospective estimate of lifetime cumulative exposure to asbestos showed a moderate correlation with the total asbestos fibre count in the autoptic lung, with the regression model explaining 38-55% of the total variance.

CONCLUSIONS

Detailed information on occupational, environmental and household exposure circumstances would be indispensable for experienced industrial hygienists and/or occupational physicians to reliably assess past exposure to amphiboles or mixed types of asbestos.

Sleepiness and safety at work among night shift NHS nurses

BACKGROUND

Sleepiness associated with night shift working (NSW) is known to adversely affect workers' health and well-being. It has been associated with adverse safety outcomes and is a recognized workplace hazard among healthcare workers.

AIMS

This study was aimed to assess the prevalence of self-reported sleepiness in NSW nurses and midwives. This study also explored the consequences of sleepiness on safety at work and driving.

METHODS

A cross-sectional study of NSW nurses and midwives was conducted at an National Health Service (NHS) hospital trust from 16 March 2020 to 1 June 2020. Data were collected by online questionnaire and included information on demographics, shift work and safety aspects. Sleepiness was assessed with the Epworth Sleepiness Scale (ESS).

RESULTS

Data collection coincided with the first coronavirus pandemic peak in England. Out of 1985 eligible NSW nurses and midwives, 229 participated in the study, with a response rate of 12%. The prevalence of sleepiness was 28%. Following a night shift, 49% of nurses reported nodding off at the wheel and 44% reported a near-miss car accident in past 12 months. An abnormal ESS score was significantly associated with near-miss car accidents (odds ratio [OR] 2.75, 95% confidence interval [CI] 1.31-5.77) and with low confidence in undertaking complex tasks at night (OR 2.64, 95% CI 1.20-5.84).

CONCLUSIONS

More than a quarter of NSW nurses and midwives reported excessive daytime sleepiness although, due to the low response rate, this may not be representative. Adverse driving events were common. Elevated ESS scores correlated well with safety issues relating to work and driving.

Shift rotation scheme, sleepiness and sleep quality in night-shift workers

BACKGROUND

Shift rotation schemes can influence workers' tolerance of night-shift work and its impact on health.

AIMS

This study was aimed to assess the influence of shift work rotation schemes on sleepiness and sleep quality.

METHODS

We conducted a cross-sectional study of 145 male workers, 77 from a ceramic tile factory on a fixed, forward-rotating shift work scheme, and 68 from a dockyard company, working on-call night shifts. Participants self-administered the Epworth Sleepiness Scale (ESS) and the Pittsburgh Sleep Quality Index (PSQI) questionnaires and provided data on demographic and lifestyle variables. We set two logistic regression models to predict the risk of daytime sleepiness and poor sleep quality as a function of night-shift work and on-call night shifts, adjusting for personal and lifestyle covariates.

RESULTS

Marital status, body mass index, smoking and alcohol intake did not affect ESS and PSQI scores, nor did they differ between the two cohorts. Night-shift workers from both cohorts were more likely to have a PSQI score ≥6, suggestive of poor sleep quality, with no variation between the two cohorts. ESS scores suggestive of daytime sleepiness were strongly associated with on-call night shifts among dockyard workers for (odds ratio = 13.4; 95% confidence interval 2.9-63.9), in respect the regular, forward-rotating night-shift work among ceramic tile factory workers.

DISCUSSION

Daytime sleepiness occurred more frequently among dockyard workers working on-call night shifts. Poor sleep quality occurred more frequently among night-shift workers, but it did not differ between the two companies.

The preventable burden of work-related ill-health

Background

The fraction of ill-health overall attributable to occupational conditions has not been extensively evaluated, thus contributing to the perception of a lesser relevance of education and research in occupational health in respect to other fields of medical research and practice.

Aims

To assess the relevance of work-related conditions on the aetiology of human ill-health in different health domains.

Methods

We extracted the risk estimates associated with heritability and with occupational risk factors for chronic lymphocytic leukaemia (CLL), major depressive disorder (MDD) and long QT syndrome (LQTS) from 13 published international reports. The selection criteria for the eligible studies were: genome-wide studies, or studies of the occupational risk factors associated with one of the three diseases of interest. We calculated and compared the respective population attributable fraction for the combined occupational risk factors, and for heritability.

Results

We estimated that occupational risk factors would account for 12% (95% confidence interval (CI) 4-19) of CLL, 11% (95% CI 7-15) of MDD and 10% (95% CI 2-13) of LQTS burden in the general population. The corresponding figures for heritability would be 16% (95% CI 11-22), 28% (95% CI 20-5) and 17% (95% CI 7-27).

Conclusions

More efforts in capacity building and research in occupational health are warranted aiming to prevent ill-health and to preserve a productive life for the ageing work population.

Glucose-6-Phosphate Dehydrogenase Deficiency and Lung Cancer: A Hospital Based Case-Control Study

A hospital based case-control study was conducted to test the hypothesis of a lower lung cancer risk in G6PD-deficient subjects. Cases were 156 male patients with lung cancer, admitted to « Binaghi » Hospital, Local Health Unit (USL) 20, Cagliari (Italy), between January 1984 and November 1986. Controls were 235 male patients, admitted to the same hospital In the same time period, for diseases other than cancer (all types) and hemolytic anemia. No decrease of the lung cancer risk was found in G6PD-deficient subjects. This result, in line with recent reports in the literature, suggests that the genetic condition of G6PD deficiency does not provide significant protection against the development of lung cancer in humans.

Methodological Issues in a Multicentric Study of Gastric Cancer and Diet in Italy: Study Design, Data Sources and Quality Controls

The authors examine the problems of planning and conducting a multicentric case-control study on diet and gastric cancer in Italy. The solutions chosen for the study design, cases and controls identification, dietary interview, production of a common protocol for the field work are discussed. Results on the evaluation of the quality and comparability of collected data are presented. Further, compliance of cases and controls to the interview and to the blood and urine sampling with reasons of non-response are shown. Finally, the phases of the study and the methods for improving and controlling omogeneity among Centers are summarized.

Estimates of Environmental Exposure to Radiofrequency Electromagnetic Fields and Risk of Lymphoma Subtypes

We investigated the association between environmental exposure to radiofrequency electromagnetic fields (RF-EMF) and risk of lymphoma subtypes in a case-control study comprised of 322 patients and 444 individuals serving as controls in Sardinia, Italy in 1998-2004. Questionnaire information included the self-reported distance of the three longest held residential addresses from fixed radio-television transmitters and mobile phone base stations. We georeferenced the residential addresses of all study subjects and obtained the spatial coordinates of mobile phone base stations. For each address within a 500-meter radius from a mobile phone base station, we estimated the RF-EMF intensity using predictions from spatial models, and we performed RF-EMF measurements at the door in the subset of the longest held addresses within a 250-meter radius. We calculated risk of lymphoma and its major subtypes associated with the RF-EMF exposure metrics with unconditional logistic regression, adjusting by age, gender and years of education. In the analysis of self-reported data, risk associated with residence in proximity (within 50 meters) to fixed radio-television transmitters was likewise elevated for lymphoma overall [odds ratio = 2.7, 95% confidence interval = 1.5-4.6], and for the major lymphoma subtypes. With reference to mobile phone base stations, we did not observe an association with either the self-reported, or the geocoded distance from mobile phone base stations. RF-EMF measurements did not vary by case-control status. By comparing the self-reports to the geocoded data, we discovered that the cases tended to underestimate the distance from mobile phone base stations differentially from the controls ( P = 0.073). The interpretation of our findings is compromised by the limited study size, particularly in the analysis of the individual lymphoma subtypes, and the unavailability of the spatial coordinates of radio-television transmitters. Nonetheless, our results do not support the hypothesis of a link between environmental exposure to RF-EMF from mobile phone base stations and risk of lymphoma subtypes.

Occupational exposure to endocrine disruptors and lymphoma risk in a multi-centric European study

BACKGROUND

Incidence rates of lymphoma are usually higher in men than in women, and oestrogens may protect against lymphoma.

METHODS

We evaluated occupational exposure to endocrine disrupting chemicals (EDCs) among 2457 controls and 2178 incident lymphoma cases and subtypes from the European Epilymph study.

RESULTS

Over 30 years of exposure to EDCs compared to no exposure was associated with a 24% increased risk of mature B-cell neoplasms (P-trend=0.02). Associations were observed among men, but not women.

CONCLUSIONS

Prolonged occupational exposure to endocrine disruptors seems to be moderately associated with some lymphoma subtypes.

A meta-analysis of Hodgkin lymphoma reveals 19p13.3 TCF3 as a novel susceptibility locus

Recent genome-wide association studies (GWAS) of Hodgkin lymphoma (HL) have identified associations with genetic variation at both HLA and non-HLA loci; however, much of heritable HL susceptibility remains unexplained. Here we perform a meta-analysis of three HL GWAS totaling 1,816 cases and 7,877 controls followed by replication in an independent set of 1,281 cases and 3,218 controls to find novel risk loci. We identify a novel variant at 19p13.3 associated with HL (rs1860661; odds ratio (OR)=0.81, 95% confidence interval (95% CI) = 0.76-0.86, P(combined) = 3.5 × 10(-10)), located in intron 2 of TCF3 (also known as E2A), a regulator of B- and T-cell lineage commitment known to be involved in HL pathogenesis. This meta-analysis also notes associations between previously published loci at 2p16, 5q31, 6p31, 8q24 and 10p14 and HL subtypes. We conclude that our data suggest a link between the 19p13.3 locus, including TCF3, and HL risk.

[Prevalence of atopic conditions in patients with occupational contact allergic dermatitis: comparison between diagnostic tool]

BACKGROUND

Occupational allergic contact dermatitis (OACD), to which atopy contributes to a as yet unspecified degree, accounts for a considerable number of work-related diseases.

OBJECTIVES

We studied the prevalence of atopy in OACD patients. We also compared the ability of prick tests and specific IgE assays to detect it.

METHODS

In 329 patients diagnosed with OACD at the Occupational Medicine Unit of Cagliari University Hospital between 2000 and 2009, we aimed at detecting atopic conditions with prick tests and IgE assays specific for allergens most frequently responsible for atopic reaction. A kappa test was used to assess concordance between the two assays. The 2 test for trend was used in the analysis of prevalence of atopy by age at diagnosis.

RESULTS

A positive response was more frequently detected with prick tests (35.9%) than the specific IgE assays (31%). IgE assays for all the allergens we tested were more frequently positive among males (p range = 0.001-0.037). With either test, the highest observed prevalence of a positive response was to Dermatophagoides pteronyssinus. A significantly inverse trend with increasing age in the prevalence ofpositive reaction to Dermatophagoides pteronyssinus, Phleum pratense and Olea europaea (olive) allergens was also observed. The concordance between the two tests ranged between good (Dermatophagoides pteronyssinus, Phleum pratense and Olea europaea and moderate Artemisia vulgaris (mugwort) and Parietaria judaica.

CONCLUSIONS

Our results showed a prevalence of atopic conditions in 31-35.9% of OACD patients.

RESULTS

with the two assays were largely consistent, indicating that both prick tests an specific IgE assays are valid diagnostic tools for atopy.

Occupational exposure to trichloroethylene and risk of non-Hodgkin lymphoma and its major subtypes: a pooled InterLymph [correction of IinterLlymph] analysis

OBJECTIVES

We evaluated the association between occupational exposure to trichloroethylene (TCE) and risk of non-Hodgkin lymphoma (NHL) in a pooled analysis of four international case-control studies.

METHODS

Overall, the pooled study population included 3788 NHL cases and 4279 controls. Risk of NHL and its major subtypes associated with TCE exposure was calculated with unconditional logistic regression and polytomous regression analysis, adjusting by age, gender and study.

RESULTS

Risk of follicular lymphoma (FL), but not NHL overall or other subtypes, increased by probability (p=0.02) and intensity level (p=0.04), and with the combined analysis of four exposure metrics assumed as independent (p=0.004). After restricting the analysis to the most likely exposed study subjects, risk of NHL overall, FL and chronic lymphocytic leukaemia (CLL) were elevated and increased by duration of exposure (p=0.009, p=0.04 and p=0.01, respectively) and with the combined analysis of duration, frequency and intensity of exposure (p=0.004, p=0.015 and p=0.005, respectively). Although based on small numbers of exposed, risk of all the major NHL subtypes, namely diffuse large B-cell lymphoma, FL and CLL, showed increases in risk ranging 2-3.2-fold in the highest category of exposure intensity. No significant heterogeneity in risk was detected by major NHL subtypes or by study.

CONCLUSIONS

Our pooled analysis apparently supports the hypothesis of an increase in risk of specific NHL subtypes associated with occupational exposure to TCE.

Cigarette smoking and risk of Hodgkin lymphoma and its subtypes: a pooled analysis from the International Lymphoma Epidemiology Consortium (InterLymph)

BACKGROUND

The etiology of Hodgkin lymphoma (HL) remains incompletely characterized. Studies of the association between smoking and HL have yielded ambiguous results, possibly due to differences between HL subtypes.

PATIENTS AND METHODS

Through the InterLymph Consortium, 12 case-control studies regarding cigarette smoking and HL were identified. Pooled analyses on the association between smoking and HL stratified by tumor histology and Epstein-Barr virus (EBV) status were conducted using random effects models adjusted for confounders. Analyses included 3335 HL cases and 14 278 controls.

RESULTS

Overall, 54.5% of cases and 57.4% of controls were ever cigarette smokers. Compared with never smokers, ever smokers had an odds ratio (OR) of HL of 1.10 [95% confidence interval (CI) 1.01-1.21]. This increased risk reflected associations with mixed cellularity cHL (OR = 1.60, 95% CI 1.29-1.99) and EBV-positive cHL (OR = 1.81, 95% CI 1.27-2.56) among current smokers, whereas risk of nodular sclerosis (OR = 1.09, 95% CI 0.90-1.32) and EBV-negative HL (OR = 1.02, 95% CI 0.72-1.44) was not increased.

CONCLUSION

These results support the notion of etiologic heterogeneity between HL subtypes, highlighting the need for HL stratification in future studies. Even if not relevant to all subtypes, our study emphasizes that cigarette smoking should be added to the few modifiable HL risk factors identified.

Menstrual and reproductive factors, and hormonal contraception use: associations with non-Hodgkin lymphoma in a pooled analysis of InterLymph case-control studies

BACKGROUND

The two most common forms of non-Hodgkin lymphoma (NHL) exhibit different sex ratios: diffuse large B-cell lymphoma (DLBCL) occurs more frequently in men and follicular lymphoma (FL) more frequently in women. Looking among women alone, this pooled analysis explores the relationship between reproductive histories and these cancers.

MATERIALS AND METHODS

Self-reported reproductive histories from 4263 women with NHL and 5971 women without NHL were pooled across 18 case-control studies (1983-2005) from North America, Europe and Japan. Study-specific odd ratios (ORs) and confidence intervals (CIs) were estimated using logistic regression and pooled using random-effects meta-analyses.

RESULTS

Associations with reproductive factors were found for FL rather than NHL overall and DLBCL. In particular, the risk of FL decreased with increasing number of pregnancies (pooled OR(trend) = 0.88, 95% CI 0.81-0.96). FL was associated with hormonal contraception (pooled OR = 1.30, 95% CI 1.04-1.63), and risks were increased when use started after the age of 21, was used for <5 years or stopped for >20 years before diagnosis. DLBCL, on the other hand, was not associated with hormonal contraception (pooled OR = 0.87, 95% CI 0.65-1.16).

CONCLUSIONS

Hormonal contraception is associated with an increased risk of FL but not of DLBCL or NHL overall.

Biological monitoring of low-level exposure to benzene

INTRODUCTION

Conflicting opinions exist about the reliability of biomarkers of low-level exposure to benzene. We compared the ability of the urinary excretion of trans,trans-muconic acid (t,t-MA), s-phenilmercapturic acid (s-PAMA) and urinary benzene (U-Benz) to detect low level occupational and environmental exposure to benzene.

METHODS

We monitored airborne benzene by personal air sampling, and U-Benz, s-PMAI, t,t-MA and cotinine (U-Cotinine) in spot urine samples, collected at 8 am and 8 pm, in 32 oil refinery workers and 65 subjects, randomly selected among the general population of urban and suburban Cagliari, Italy. Information on personal characteristics, diet and events during the sampling day was acquired through in person interviews.

RESULTS

The median concentration of airborne benzene was 25.2 microg/m3 in oil refinery workers, and 8.5 microg/m3 in the general population subgroup. U-Benz in morning and evening samples was significantly more elevated among oil refinery workers than the general population subgroup (p = 0.012, and p = 7.4 x 10(-7), respectively) and among current smokers compared to non-smokers (p = 5.2 x 10(-8), and p = 5.2 x 10(-5) respectively). Benzene biomarkers and their readings in the two sampling phases were well correlated to each other. The Spearman's correlation coefficient with airborne benzene was significant for U-Benz in the evening sample, while no correlation was seen with t,t-MA and s-PMA readings in either samplings. The two benzene metabolites were frequently below limit of detection (LOD), particularly among the general population study subjects (17-9% and 39%, for t,t-MA and s-PMA respectively). Morning U-Cotinine excretion showed a good correlation with U-Benz in the morning and in the evening sampling (p < 0.001), and with s-PMA in the evening sample (p < 0.001), but not with t,t-MA in either samplings. t,t-MA in the evening sample was the only biomarker showing a moderate inverse correlation with BMI (p < 0.05). The multiple regression analysis adjusting by BMI and number of cigarettes smoked during the day confirmed the results of the univariate analysis.

DISCUSSION

Our results suggest that unmetabolized U-Benz would allow a more reliable biomonitoring of low-level exposure to benzene than s-PMA and t,t-MA.

[Cancer risk among shift workers: a review]

INTRODUCTION

According to IARC, shift work resulting in disruption of circadian rhythm is a probable human carcinogen (Group 2A).

METHODS

We examined the scientific literature on the carcinogenic risk among shift workers for risk assessment purposes.

RESULTS

Clock genes polymorphisms might contribute with suppression of melatonin synthesis, immuno-suppression from sleep deprivation, individual habits associated with shift work, and low vitamin D levels, in increasing risk of breast cancer, prostate cancer and lymphoma among shift workers.

CONCLUSION

Although the epidemiological evidence seems scanty, the hypothesis that shift work-related sleep deprivation would contribute to increasing cancer risk seems based on solid ground.

[Risk of major lymphoma subtypes and use of mobile phones]

INTRODUCTION

We explored the association between use of mobile phones and lymphoma risk in a case-control study.

METHODS

We conducted unconditional logistic regression analysis in 322 lymphoma cases and 446 population controls, adjusting by age, gender and education.

RESULTS

Risk of lymphoma (all types; OR = 1.5; 95% CI 1.0 - 2.1), and chronic lymphocytic leukaemia (OR = 1.8; 95% CI 1.0 - 3.4) was elevated in subjects reporting use of mobile phones, but it decreased with duration of use, and years from first purchase.

CONCLUSIONS

Our contradictory findings would not support the aetiological nature of the observed associations.

[Occupational and environmental cancer in southern Sardinia: a survey on ten years of hospitalizations]

Based on hospital discharges in 1001-2010, we calculated risk of tumours with an elevated occupational and environmental etiological fraction by health district of residence within the Local Health Unit (LHU) N. 8 of Sardinia. With reference to the age and gender-specific hospitalization rates of the whole LHU, residents in the urban Cagliari health district showed an excess risk of haemolymphopoietic cancer (RR = 1.07; 95% CI 1.03-1.12) and bladder cancer (RR = 1.10; 95% CI 1.05-1.16); in both instances, risks were higher among female residents. The highest excess risk for lung cancer was observed among residents in the Quartu-Parteolla health district (RR = 1.13; 95% CI 1.05-1.21), and it was slightly higher among male residents. The results appear to confirm the role of urban factors in increasing cancer risk.

[Assessment of congenital malformation risk in the progeny of the military and civilian personnel of the Salto di Quirra military base: preliminary results]

INTRODUCTION

We evaluated the congenital malformation rate in the progeny of the personnel of the Salto di Quirra military base in Sardinia.

METHODS

During 2011, we gathered questionnaire information on the reproductive history of 389 employees, more then 99% of those eligible for routine health surveillance.

RESULTS

the observed congenital malformation rate (20.1 x 10(-3), 95% CI 6.3 - 33.8) was lower than that reported by the Italian Registries of Congenital Malformations, and it did not vary by exposure to radiofrequency, elf electromagnetic fields, and solvents, and by jobs associated with alleged exposure to nanoparticles or alpha radiation.

CONCLUSIONS

Our findings suggest that the documented or alleged occupational exposures among the PISQ workforce did not increase the congenital malformation rate in the progeny.

Meta-analyses of published epidemiological studies, 1979-2006, point to open causal questions in silica-silicosis-lung cancer research

BACKGROUND AND OBJECTIVES

Following up on a previous meta-analysis of lung cancer risk in individuals without silicosis, we provide more detailed results of silica associated lung cancer risk in both silicotics and non-silicotics. The objective was to examine in depth whether current data allows to answer the pressing question "does silica cause lung cancer in the absence of silicosis"?

METHODS

We updated earlier meta-analyses of silicosis and lung cancer and compared the results with our 2009 meta-analysis of risks in individuals without silicosis. We performed fixed (FE) and random (RE) effects meta-analyses, calculated heterogeneity statistics, stratified the study material, performed sensitivity analyses with modified study results and meta-regressions to detect effect modification.

RESULTS

In silicotics, lung cancer risks were found to be doubled in 38 studies (FE: RR = 2.1; 95% CI = 2.0-2.3). In non-silicotics, eight studies without smoking adjustment suggested marginally elevated risks (FE: RR = 1.2; 95% CI = 1.1-1.3; RE: RR = 1.2; 95% CI =1.0-1.4) but three studies which were controlled for smoking showed null results (FE and RE: RR = 1.0; 95% CI = 0.8-1.3). Heterogeneity was substantial but could be linked to study characteristics, like sector of industry, and other second-level data in meta-regression. As no excess was observe dfor other smoking-related effects in studies ofllung cancer among non-silicotics, smoking was not considered to be an important confounder or modifier. CONCLUSIONn: Our meta-analyses further substantiate evidence of a strong association between silicosis and lung cancer. However, questions remain regarding lung cancer caused by silica in non-silicotics. Ideally, future investigations should consider the entire exposure-response range between silica exposure, silicosis development and lung cancer occurrence, and analyze data in terms of processes taking intermediate confounding into account.

The exposure metric: does including time since exposure in the calculation of working lifetime exposure provide a better understanding of disease risk than the cumulative exposure?

BACKGROUND

When exposure measurements are available for occupational epidemiology studies, the cumulative exposure (the sum of the products of duration and exposure intensity at all jobs) is generally selected as the summary metric for chronic diseases. For silica exposures, a metric that weights each exposure by the number of years since it occurred has been suggested as more biologically relevant. Comparative reports of analyses using both metrics have not been found in the literature, however.

METHODS

We calculated both metrics for silica exposure, and evaluated exposure-response relations for lung cancer and silicosis in two separate case-control studies.

RESULTS

Generally the results were consistent, due to the high correlation between the two metrics and the fact that the rate of time away from work during the employment years was low.

CONCLUSION

The significant relation between exposure and silicosis using the weighted metric provides additional point estimates of risk, adding to the understanding of exposure-response.

[Results of a health surveillance program for health care workers exposed to a patient affected by tuberculosis]

A health surveillance program was implemented in 71 health care workers (HCW) exposed to a patient with active TB infection. A two-step tuberculin skin test (TST) was performed in all the exposed, and a QuantiFERON-TB Gold (QTF) test was scheduled for positive TST subjects. Clinical-radiological surveillance (CRS) was scheduled for subjects positive to TST and QTF or symptomatic. Thirty eight percent HCW were TST positive; 19% of them were also QTF positive and were referred to CRS. No clinical TB was observed among the exposed HCW. Comprehensive health surveillance allows to increase risk perception, compliance to HS and to reduce cost in respect to less cost-effective practices.

[Retrospective exposure assessment in occupational epidemiology: principles and methods]

INTRODUCTION

Occupational histories in case-control studies typically include a variety of past exposure circumstances and no monitoring data, posing serious challenges to the retrospective assessment of occupational exposures. METHODS. I will use examples from the EPILYMPH case-control study on lymphoma risk to introduce principles and methods of retrospective assessment of occupational exposures.

RESULTS

Exposure assessment consists in several indicators, such as frequency and intensity of exposure, as well as a confidence score, expressing the occupational expert own judgement on the reliability of the assessment itself. Testing the null hypothesis from multiple perspectives allows boosting inference: while trends by the individual exposure indicators were all of borderline statistical significance, testing the association between CLL risk and exposure to ethylene oxide with the Fisher's test for combined testing of multiple probabilities yielded a p-value of 0.003. Using the occupational expert assessment as the gold standard, the specificity of a prior job-exposure matrix for benzene was 93%, and its sensitivity 40%., with a positive and negative predictive values ranging 71-77%.

CONCLUSION

Once bias can be excluded, assuming a true association between exposure and disease, retrospective exposure assessment only under estimates the true risk, which size also depends on frequency of the exposure itself.

[Electrocardiogram changes in shift workers]

BACKGROUND

Besides a significant deterioration in their family and personal life, shift workers also suffer health problems ranging from chronic fatigue to gastro-intestinal disorders, changes in sleep rhythm and cardiovascular disease, including arrhythmia and ischaemic heart disease.

OBJECTIVES

The aim of the study was to assess the prevalence of electrocardiographic changes, such as conduction disorders, alterations in the repolarization phase and frequency-adjusted QT interval (QTc) in relation to shift work.

METHODS

We conducted a cross sectional survey of 125 male subjects, 60 of whom worked fixed hours, and 65 were shift workers on two different schedules: 32 were on duty for 24 hours followed by 96 hours rest, and 33 worked 8-hour shifts (3 x 8). During periodical health assessment we examined their electrocardiograms (ECG), classified the morphology and measured the QTc interval.

RESULTS

The QTc interval did not differ by type of work shift or by the presence of morphological changes in the ECG, including concurrent conduction disorders, or alterations in the repolarization phase. However, unlike day workers and 24-h shift workers, the QTc interval tended to increase with age among 8-h shift workers (r = 0.338; p = 0.05). Also, risk of conduction disorders was moderately, but not significantly, elevated among 8-h shift workers compared with subjects working fixed hours (OR = 1.9; I.E 95% 0.6, 5.7).

CONCLUSIONS

Our study did not reveal significant changes in the ECG morphology in relation to the type of work shift.

Glucose-6-phosphate dehydrogenase deficiency protects against coronary heart disease

Previous studies suggest a reduction in cardiovascular risk among subjects expressing the glucose-6-phosphate dehydrogenase (G6PD, EC 1.1.1.49) deficient phenotype. We aimed to test this hypothesis in male subjects expressing the G6PD-deficient phenotype vs wild type G6PD. In a case-control study we examined consecutive patients admitted for acute myocardial infarction or unstable angina, and controls admitted for diagnoses other than coronary heart disease (CHD). The G6PD phenotype was determined by measuring the enzyme activity in erythrocytes, as the absorbance rate change due to NADPH reduction. The CHD risk associated with the G6PD phenotype was assessed with unconditional logistic regression. G6PD-deficient subjects were less frequently represented among cases (11.8%) than among controls (18.6%, p=0.002). The genetic condition of G6PD deficiency conveyed a significant reduction in CHD risk (OR=0.6; 95% CI 0.4 to 0.9). We confirm the hypothesis that subjects with the G6PD-deficient phenotype are less prone to CHD. We suggest that such a protective effect may be ascribable to a reduced 3-hydroxy-3-methylglutaryl-coenzyme A reductase (HMG-CoA R) activity, a statin-like effect, as well as to a downregulation in NADPH oxidase activity with a consequent reduction in oxygen-free radical production.

Plasma polychlorobiphenyl and organochlorine pesticide level and risk of major lymphoma subtypes

BACKGROUND

There is conflicting epidemiological evidence concerning an increase in risk of non-Hodgkin's lymphoma (NHL) associated with elevated blood levels of persistent organochlorine (OC) pesticides and polychlorobiphenyls (PCBs).

METHODS

We measured the concentration of 17 OC pesticides, including hexachlorobenzene (HCB), four lindane isomers (alpha-, beta-, gamma- and delta-hexachlorocyclohexane (HCH)), two chlordane species (heptachlor and oxy-chlordane), four cyclodiene insecticides (aldrin, dieldrin, endrin and mirex), six dichloro-diphenyl-trichloroethane (DDT) isomers and nine PCB congeners (PCBs 28, 52, 101, 118, 138, 153, 170, 180 and 194) in plasma samples of 377 subjects, including 174 NHL cases and 203 controls from France, Germany and Spain. The risk of NHL and its major subtypes associated with increasing blood levels of OC pesticides and PCBs was calculated using unconditional logistic regression.

RESULTS

Risk of NHL, diffuse large B cell lymphoma (DLBCL) and chronic lymphatic leukaemia (CLL) did not increase with plasma levels of HCB, beta-HCH, p,p'-dichloro-diphenyl-dichloroethylene (DDE), or total and individual PCBs or their functional groups, in the overall study population. Substantial heterogeneity in DLBCL risk associated with immunotoxic PCBs (p = 0.03) existed between the Spanish subgroup (odds ratio (OR) for immunotoxic PCB plasma level above the median vs below the median was 0.7, 95% CI 0.3 to 1.6) and the French and German subgroups combined (OR 3.2, 95% CI 0.9 to 11.5).

CONCLUSION

We did not find evidence of an association between NHL risk and plasma level of OC pesticides and PCBs.

Lung cancer among silica-exposed workers: the quest for truth between chance and necessity

BACKGROUND

In 1997, IARC upgraded crystalline silica to a Group 1 human carcinogen. However, the IARC report itself acknowledged variations in risk depending on inherent characteristics of the crystalline silica or external factors affecting its biological activity or distribution of its polymorphs.

METHODS

We reviewed silica physical and physico-chemical properties and how such properties may affect its interaction with the target cells. Studies of silica, silicosis and lung cancer published from 1997 onwards are then reviewed in the search of any new advances in knowledge about silica carcinogenicity. Finally, other possible confounding factors contributing to inconsistent findings on silica, silicosis, and lung cancer are reviewed.

RESULTS

Host factors, physico-chemical characteristics of the surface of silica particles, exposure circumstances, and the mineral ore composition experimentally affect the ability of silica particles of inducing release of reactive oxygen species (ROS) and TNF-alpha by alveolar macrophages, possibly accounting for the great variation in lung cancer risk among dust exposed workers across the individual studies. Most recent epidemiological studies do not consider such complex pattern of modifying factors, and they keep replicating inconsistent findings. The hypothesis of a silicosis-mediated pathway, although more consistent from an epidemiological perspectives, and reassuring in terms of the effectiveness of current standards in preventing lung cancer risk among silica exposed workers, does not seem to explain elevated risks at low silica exposure levels.

CONCLUSION

Future studies of lung cancer risk among workers exposed to silica-containing dust should consider measurement of ROS and TNF-alpha release by workplace dust samples as intermediate end-points predicting lung cancer risk better than silica concentration, allowing to more effectively address preventive action.

[G6PD phenotype and red blood cell sensitivity to the oxidising action of chlorites in drinking water]

Chlorine dioxide is widely used to replace sodium hypochlorite in the disinfection of surface waters for human consumption, in order to avoid or reduce the formation of organohalogenated compounds with mutagenic and carcinogenic activity. However, chlorine dioxide may lead to the formation of by-products, such as chlorites and chlorates, that have an oxidative effect on the blood corpuscled fraction. In this investigation, blood crasis was assessed in relation to the G6PD phenotype and the consumption of tap water, disinfected with chlorine dioxide, or bottled mineral water from non-disinfected underground sources. The results show that the effect of oxidative stress resulting from the uptake of chlorites with drinking water is not additive to the effect due to G6PD deficiency. The observed change in haematological parameters, including those related to the G6PD polymorphism, is always within the normal range. However, it is still possible that more relevant changes would follow exposure to chlorites concentrations greater than that observed in the present study.

Classic Kaposi's sarcoma in southern Sardinia, Italy

The first examination of classical Kaposi's sarcoma incidence in southern Sardinia (Italy) in 1998–2002 found the highest rate recorded in the island of 2.49 per 100 000 per year (standardised).

[Causal link in the assessment of the relationship between neoplastic diseases and occupational and environmental exposure in the judicial field]

IARC evaluations of the carcinogenic risk to humans, although based on epidemiological and experimental studies, derive their value from the consensus among committee members on a decision based on the current status of knowledge, not from the studies themselves, nor from their summary evaluation. A judiciary setting, based on the opinion of an individual expert, or on the evaluation of the most updated state of the knowledge by a group of experts selected in non scientific settings, or even worse on the evaluation of a specific case with ad hoc epidemiological studies, cannot confute such decisions. Therefore, causal links already defined within the scientific community, such as between exposures in the IARC category 1 and specific cancer sites, should be accepted also in legal trials to establish individual responsibility in case of excess exposures for the general and/or the working population resulting from violation or omission of preventive duties, when those diseases follow such excess exposures. If no violation or omission occurred, a civil responsibility has to be defined when either a disease with established link with the given exposure occurs, or a disease for which no such a level of consensus exists in the scientific community, but for which the legal trial has reached a positive decision. In such instances, if omissions or law violations occurred, the legal trial carries the burden of establishing a causal link between such omissions and violations and the damage for the individual worker or citizen.

[Retrospective estimate of occupations exposure to solvents. Methodology used in the Epilymph study]

To assess occupational exposure to solvents in the EPILYMPH multicentre case-control study on lymphoma, we combined experts assessment, based on detailed description of work tasks from questionnaires, with the use of job-exposure matrices (jem). Whenever occupations and/or industries conveying exposure to occupational risk factors for lymphoma occur in their work history, the interviewer selects the respective questionnaire in a set of 15 special questionnaires and applies it to the study subject. All jobs lasting one year or more in the work histories are coded using the 1968 ILO ISCO, and the 1996 EEC Classification of Economic activities (NACE). A priori jems for 3 categories of solvents (solvents in general, chlorinated aliphatic hydrocarbons and benzene-toluene-xylene combination) and 10 individual agents have been constructed based on the same coding systems, by which each occupationa/industry combination receives a unique score for confidence and intensity of exposure to each agent and group of solvents. Trained industrial hygienists (IH's) in each participating country examine the general and special questionnaires and classify three indices of exposure for each agent under scrutiny: confidence, which represents the IH degree of certainty that the worker has been exposed to the agent; frequency, which is expressed in a 4-step scale according to the proportion of working time involving contact with the agent; and intensity, which is also expressed in a scale, defined by quantitative cut-points, when available, or benchmark occupations, when no quantitative information is available from the questionnaires. The IH finally notes his degree of reliance on his own exposure estimate. The IH supports his exposure assessment with confidence and intensity scores provided by the jem when questionnaire information is so poor that it does not provide any clue about exposure, or he relies poorly on his own exposure estimate. Such a procedure is conceptually alike to statistical procedures to fill missing data in a given series.

Elusive amines and primary headaches: historical background and prospectives

Although the role of trace amines such as tyramine, octopamine and synephrine in the pathogenesis of migraine has been debated for decades, this issue remains still unresolved. In spite of a relevant body of work, the inability to demonstrate specific receptors for these compounds and the lack of sensitive non-radioactive methods for the detection of trace amines in biological samples have limited their investigation in humans. However, the recent identification of a new, large family of G protein-coupled receptors, some of which bind and are activated by trace amines, has focused renewed attention on these compounds. This discovery, together with the possibility of providing novel insights for evaluation of the pathophysiological role of trace amines in primary headaches, may offer new opportunities for pharmacological strategies acting on these receptors. In light of the new scientific background, this review outlines a historical perspective and summarizes evidence supporting a role of trace amines in the pathogenesis of migraine and cluster headache.

[Thoracic lymphadenopathy due to vascular transformation of lymph node sinuses associated with upper limb edema in a chronic hemodialysis patient with congestive heart failure]

BACKGROUND

Vascular transformation of lymph node sinuses (VTLS) is a rare disorder characterized by transformation of lymph node sinuses into endothelium-lined capillary-like channels. This phenomenon was originally discovered by accident whilst examining regional lymph nodes draining cancer. However, it has been found in association with other conditions associated with lympho venous congestion and distension, such as congestive heart failure (CHF) or even lymphoadenopathy alone.

CASE REPORT

We describe the clinical case of a male dialysis patient with CHF (secondary to ischemic-hypertensive cardiac failure) who developed gross edema of the upper left limb on the arteriovenous fistula (AVF) side. Edema appeared within a month after carotid endoarteriectomy following approximately twenty years of chronic hemodialysis. Doppler ultrasound with other investigations showed that subclavian and upper cava veins were patent, but revealed many enlarged lymph nodes in the upper left thorax and in the left axilla. Suspicion of lymphoproliferative disease or metastatic involvement was raised and a lymph node biopsy was performed, revealing VTLS. Bone marrow biopsy and abdominal tomographies showed no mass or a proliferative disorder. Based on a hypothesis of an association between upper limb edema and ipsilateral AVF, the AVF was tied. The upper limb edema decreased dramatically within weeks, whilst RRT was continued by means of a central venous catheter. However, a few months later the patient's condition worsened; he developed relapsing pleural effusions and eventually died. Post-mortem examination revealed severe ischemic-calcific cardiopathy and showed that major thoracic and brachial vessels were patent whilst most thoracic and hilar lymph nodes showed VTLS and fibrosis.

CONCLUSIONS

We believe that in our patient CHF was the primary cause of thoracic adenomegaly and that CHF, together with venous hypertension at the left fistula's arm, caused ipsilateral limb edema. Thus, adenomegaly due to VTLS could represent an accompanying feature even in upper limb edema in chronic hemodialysis patients. To our knowledge, this is the first report of such an association. In our patient months were "lost" because we thought that limb edema was secondary to the adenomegaly. It is important that clinicians working in dialysis units are aware that when upper limb edema is present, adenomegaly might just be an accompanying symptom, especially in case of concomitant diagnosis of CHF.

Lung cancer risk, silica exposure, and silicosis in Chinese mines and pottery factories: the modifying role of other workplace lung carcinogens

BACKGROUND

Aims of our study were to explore whether and to what extent exposure to other lung carcinogens, or staging and clinical features of silicosis modify or confound the association between silica and lung cancer.

METHODS

We used data from a nested case-control study, conducted in the late 1980s in 29 Chinese mines and potteries (10 tungsten mines, 6 copper and iron mines, 4 tin mines, 8 pottery factories, and 1 clay mine), that included 316 lung cancer cases and 1,356 controls, matched by decade of birth and facility type. The previous analysis of these data presented results by type of mine or factory.

RESULTS

In our study, pooling all 29 Chinese work sites, lung cancer risk showed a modest association with silica exposure. Risk did not vary after excluding subjects with silicosis or adjusting the risk estimates by radiological staging of silicosis. Strong correlation among exposures prevented a detailed evaluation of the role of individual exposures. However, lung cancer risk was for the most part absent when concomitant exposure to other workplace lung carcinogens, such as polycyclic aromatic hydrocarbons (PAHs), nickel or radon-daughters, was considered. The cross classification of lung cancer risk by categories of exposure to respirable silica and total respirable dust did not show an independent effect of total respirable dust. Silicosis showed a modest association with lung cancer, which did not vary by severity of radiological staging, or by radiological evidence of disease progression, or by level of silica exposure. However, among silicotic subjects, lung cancer risk was significantly elevated only when exposure to cadmium and PAH had occurred.

CONCLUSIONS

Our results suggest that, among silica-exposed Chinese workers, numerous occupational and non-occupational risk factors interact in a complex fashion to modify lung cancer risk. Future epidemiological studies on silica and lung cancer should incorporate detailed information on exposure to other workplace lung carcinogens, total respirable dust, and on surface size and age of silica particles to understand whether and to what extent they affect the carcinogenic potential of silica.

[Sigmoid occlusion due to endometriosis. A case report]

The Authors report a case of sigmoid obstruction due to endometriosis and review the literature about. Unusual localisation and difficult preoperative differential diagnosis with IBD and bowel carcinoma are stressed. A 45-years old woman with previous history of oophorectomy was admitted at the hospital with symptomatic bowel obstruction. A barium enema showed a sigmoid stenosis thought to a carcinoma of bowel. A laparoscopic approach confirmed the diagnosis and a laparotomy was performed with a subsequent anterior resection (end-to-end anastomosis with stapler) plus myomectomy. The Authors do believed, during surgery, to be treating a carcinoma which disappeared with opening the specimen. The mucosa were intact and muscular layers so think to form a strong ring to be able to invaginate the upper colon for 3-4 cm. A stromal tumor was supposed and the definite diagnosis of endometriosis was very surprisingly. Intestinal resection to be necessary, with associated salpingo-oophorectomy and hysterectomy in older patients and treatment with oral contraceptive in younger female. Laparoscopy may be helpful in the diagnosis showing pelvic endometriosis with bowel wall involvement. Laparoscopic treatment in our opinion must be confirmed to particular situation and to well experience of surgeons.

Multifactorial aetiology of lung cancer among silica-exposed workers

In 1997, the International Agency for Research on Cancer (IARC) upgraded its evaluation of crystalline silica to a Group 1 human carcinogen. Criticism against such decision is based on the lack of consistency in experimental results across animal species, violation of an important principle for causality, such as the replication of findings under different circumstances of exposure, and the lack of a clear dose-response curve. The most recent epidemiological literature on the silica-silicosis-lung cancer link replicates the inconsistent findings that have been characterising 50 years of scientific debate in the occupational arena. Exposure circumstances capable of modifying the silica-lung cancer association include chronic bronchitis, composition of the dust mixing, particularly concerning co-occurrence of other known or probable lung carcinogens, total respirable dust, concentration of silica in respirable dust, type of crystalline silica and particle surface characteristics. The hypothesis of a silicosis-mediated pathway points toward an unspecific mechanism shared with other fibrotic conditions, for which silica might be just one of the triggers. In envisaging a multivariate multistep model of lung cancer among silica-exposed workers, silica might be considered as a "passive components of the sufficient cause", i.e., one of the associated risk factors, concurrent or subsequent to the "active component(s) of the sufficient cause" (including, for instance, smoking, asbestos, radon-daughters, arsenic, hexavalent chromium, nickel, polycyclic aromatic hydrocarbons (PAH), and diesel exhausts among the external risk factors; and DNA repair enzymes polymorphism and spontaneous inactivation of tumour suppressor genes among the internal risk factors), which adds up in modulating the tumoral development in not easily predictable directions. If silica acts as a human lung carcinogen depending on certain occupational exposure circumstances, perhaps those circumstances and not silica itself should be classified for their human carcinogenicity potential.

Incidence of non-Hodgkin's lymphoma and Hodgkin's disease in Sardinia, Italy: 1974-1993

BACKGROUND AND OBJECTIVES

The reasons for the worldwide increase in non-Hodgkin's lymphoma (NHL) are not clearly understood. We investigated whether an increasing trend over time has also occurred in the Italian region of Sardinia, the population of which exhibits peculiar genetic features, due to millenary isolation and pressure from 2,500 years of malarial endemism. We also investigated the geographic variation in NHL risk within the region.

DESIGN AND METHODS

We designed a descriptive epidemiology study of NHL among the Sardinian population by following up the incidence of this disease in the period 1974-1993. We calculated the standardized incidence rate (SIR) of NHL by year for the total population and by gender. The time trend of Hodgkin's disease (HD) was also evaluated as a comparison term and for validation purposes. We also mapped NHL risk in the 361 administrative units (communes) of the region.

RESULTS

NHL incidence in the Sardinian population over the whole study period was 7.5 x 10(-5) year(-1) (men: 8.2; women: 6.7), and increased from 4.1 in 1974 to 9.1 in 1993. The increasing trend was consistent by gender, and mostly affected subjects aged 55 years or older. Nodal and extra-nodal forms of NHL shared the same pattern of increasing incidence. Excluding the few NHL cases related to AIDS did not change the results. No such pattern was observed for HD incidence. The NHL incidence rate (age > or = 25 years) ranged from 0.0-60.0 x 10(-5) year-1 across communes. Areas at risk were located mainly in the northern part of the region, but risk among men was also elevated in the major urban area in southern Sardinia.

INTERPRETATION AND CONCLUSIONS

Our study shows that NHL incidence increased 2.2-fold in Sardinia from 1974 to 1993, a finding which is consistent with other world-wide report. The risk has risen in a few areas, mainly in central and northern Sardinia and in the major urban areas. Analytic studies are under way to investigate a broad range of risk factors, including viral, occupational, and environmental factors, that might account for our results.

Non-malignant respiratory diseases and lung cancer among Chinese workers exposed to silica

The objective of this study was to explore whether a medical history for non-malignant respiratory disease contributes to an increased lung cancer risk among workers exposed to silica. We analyzed data from a nested case-control study in 29 dusty workplaces in China. The study population consisted of 316 lung cancer cases and 1356 controls matched to cases by facility type and decade of birth who were alive at the time of diagnosis of the index case and who were identified in a follow-up study of about 68,000 workers. Age at first exposure and cigarette smoking were accounted for in the analysis. Smoking was the main risk factor for both lung cancer and chronic bronchitis. Lung cancer risk showed a modest association with silicosis and with cumulative silica exposure, which did not vary by history of previous pulmonary tuberculosis. Among subjects without a medical history for chronic bronchitis or asthma, lung cancer risk was associated with silicosis (odds ratio [OR], 1.6; 95% confidence interval [CI], 1.1 to 2.2), and it was increased in each quartile of cumulative silica exposure. However, risk was not elevated in the highest quartile (OR, 1.3, 1.6, 1.8, 1.4). Among subjects with a medical history for chronic bronchitis or asthma, lung cancer risk was associated with neither silicosis (subjects with chronic bronchitis: OR, 0.6; subjects with asthma: OR, 0.4) nor with silica exposure. In this study population, we observed a modest association of both silicosis and cumulative exposure to silica with lung cancer among subjects who were not previously diagnosed with chronic bronchitis or asthma, but not among subjects who had a medical history for either disease. Risk of lung cancer associated with silicosis or cumulative exposure to silica did not vary by previous medical history of pulmonary tuberculosis.