Cancers in concrete workers: results of a cohort study of 33,668 workers

An Update Overview on Mechanistic Data and Biomarker Levels in Cobalt and Chromium-Induced Neurodegenerative Diseases

There is increasing evidence that the imbalance of metals as cobalt (Co) and chromium (Cr) may increase the risk of development and progression of neurodegenerative diseases (NDDs). The human exposure to Co and Cr is derived mostly from industry, orthopedic implants, and polluted environments. Neurological effects of Co and Cr include memory deficit, olfactory dysfunction, spatial disorientation, motor neuron disease, and brain cancer. Mechanisms of Co and Cr neurotoxicity included DNA damage and genomic instability, epigenetic changes, mitochondrial disturbance, lipid peroxidation, oxidative stress, inflammation, and apoptosis. This paper seeks to overview the Co and Cr sources, the mechanisms by which these metals induce NDDs, and their levels in fluids of the general population and patients affected by NDDs. To this end, evidence of Co and Cr unbalance in the human body, mechanistic data, and neurological symptoms were collected using in vivo mammalian studies and human samples.

Cancer incidence among male construction workers in Korea: a standardized incidence ratio analysis, 2009-2015

OBJECTIVES

Construction workers face an elevated risk for several types of cancer. Nevertheless, there is a lack of large-scale epidemiological studies examining the risk of all cancers in construction workers. This study aimed to investigate the risk of various cancers in male construction workers using the Korean National Health Insurance Service (NHIS) database.

METHODS

We used data from the NHIS database from 2009 to 2015. Construction workers were identified using the Korean Standard Industrial Classification code. We calculated the age-standardized incidence ratios (SIRs) and 95% confidence intervals (CIs) for cancer occurrence in male construction workers compared to all male workers.

RESULTS

Compared to all male workers, the SIRs for esophageal cancer (SIR, 1.24; 95% CI, 1.07 to 1.42) and malignant neoplasms of the liver and intrahepatic bile ducts (SIR, 1.18; 95% CI, 1.13 to 1.24) were significantly higher in male construction workers. The SIRs for malignant neoplasms of the urinary tract (SIR, 1.19; 95% CI, 1.05 to 1.35) and non-Hodgkin lymphoma (SIR, 1.21; 95% CI, 1.02 to 1.43) were significantly elevated in building construction workers. The SIR for malignant neoplasms of the trachea, bronchus, and lung (SIR, 1.16; 95% CI, 1.03 to 1.29) was significantly higher in heavy and civil engineering workers.

CONCLUSIONS

Male construction workers have an increased risk for esophageal cancer, liver cancer, lung cancer, and non- Hodgkin's cancer. Our results indicate that tailored strategies for cancer prevention should be developed for construction workers.

Risk Factors for Testicular Cancer: Environment, Genes and Infections-Is It All?

The incidence of testicular cancer is steadily increasing over the past several decades in different developed countries. If on one side better diagnosis and treatment have shone a light on this disease, on the other side, differently from other malignant diseases, few risk factors have been identified. The reasons for the increase in testicular cancer are however unknown while risk factors are still poorly understood. Several studies have suggested that exposure to various factors in adolescence as well as in adulthood could be linked to the development of testicular cancer. Nevertheless, the role of environment, infections, and occupational exposure are undoubtedly associated with an increase or a decrease in this risk. The aim of this narrative review is to summarize the most recent evidence regarding the risk factors associated with testicular cancer, starting from the most commonly evaluated (cryptorchidism, family history, infections) to the newer identified and hypothesized risk factors.

Current understanding of hexavalent chromium [Cr(VI)] neurotoxicity and new perspectives

Hexavalent chromium [Cr(VI)] is a global environmental pollutant that increases risk for several types of cancers and is increasingly being recognized as a neurotoxicant. Traditionally, the brain has been viewed as a largely post-mitotic organ due to its specialized composition of neurons, and consequently, clastogenic effects were not considered in neurotoxicology. Today, we understand the brain is composed of at least eight distinct cell types - most of which continue mitotic activity throughout lifespan. We have learned these dividing cells play essential roles in brain and body health. This review focuses on Cr(VI), a potent clastogen and known human carcinogen, as a potentially neurotoxic agent targeting mitotic cells of the brain. Despite its well-established role as a human carcinogen, Cr(VI) neurotoxicity studies have failed to find a significant link to brain cancers. In the few studies that did find a link, Cr(VI) was identified as a risk for gliomas. Instead, in the human brain, Cr(VI) appears to have more subtle deleterious effects that can impair childhood learning and attention development, olfactory function, social memory, and may contribute to motor neuron diseases. Studies of Cr(VI) neurotoxicity with animal and cell culture models have demonstrated elevated markers of oxidative damage and redox stress, with widespread neurodegeneration. One study showed mice exposed to Cr(VI)-laden tannery effluent exhibited longer periods of aggressive behavior toward an "intruder" mouse and took longer to recognize mice previously encountered, recapitulating the social memory deficits observed in humans. Here we conducted a critical review of the available literature on Cr(VI) neurotoxicity and synthesize the collective observations to thoroughly evaluate Cr(VI) neurotoxicity - much remains to be understood and recognized.

The Medical Concrete Cancer of the Lung: A Unique Case Report

A 53-year-old 10 pack year smoker and concrete worker for 12 years presented to us with a lung mass proven to be small cell lung cancer on lung biopsy. An industrial terminology of concrete cancer already exists defining the wear and tear in concrete due to various interactions. The interactions of concrete and smoke on lung, predisposed and increased the risk of lung cancer probably as an additive effect which we label as the medical concrete cancer of the lung.

Genomic Instability in Exfoliated Buccal Cells among Cement Warehouse Workers

BACKGROUND

Workers in cement warehouses of Kerala are enduring long-standing exposure to cement dust, which is considered genotoxic.

OBJECTIVE

To evaluate the extent of genotoxicity and cytotoxicity caused due to exposure of cement dust among those working in cement warehouses.

METHODS

The study included 82 cement warehouse workers and 82 age-matched individuals with no exposure to cement dust. Exfoliated buccal micronucleus cytome assay (BMCyt) was performed to analyze the genotoxic and cytotoxic effects caused by inhalation of cement dust.

RESULTS

The frequency of various genotoxic and cytotoxic end markers (micronucleated cells [2-fold increase, p<0.001], nuclear buds [4-fold increase, p<0.001], binucleated cells [4-fold increase, p<0.001], karyorrhectic cells [2-fold increase, p<0.001], pyknotic cells [3-fold increase, p<0.001], and karyolytic cells [2-fold increase, p<0.001]) were higher in the exposed workers compared with unexposed group. Increase of these parameters represented an increased level of chromosomal damage, nuclear disintegration and increased cell death among exposed group compared with unexposed group.

CONCLUSION

Continuous exposure to cement dust results in increased frequency of nuclear aberrations and cellular apoptosis. This may lead to defects in genome maintenance, accelerated ageing, increased chance of oral cancer and neurodegenerative disorders in those occupationally exposed to cement dust.

Occupational Risk Factors for Prostate Cancer: A Meta-analysis

Prostate cancer is the second most common cancer in men worldwide. There are many occupational factors that have been suggested to cause prostate cancer. Our aim was to evaluate the evidence for causality by a literature review of occupational factors. We searched literature in Medline and SCOPUS from 1966 to June 30, 2015 to identify occupational risk factors for prostate cancer. The following risk factors were selected: farmers/agricultural workers, pesticides - whole group, and separately organophosphate and organochlorine pesticides, carbamates and triazines, cadmium, chromium, cutting fluids, acrylonitrile, rubber manufacturing, whole body vibration, shift work, flight personnel, ionizing radiation, and occupational physical activity. For each factor a literature search was performed and presented as meta-analysis of relative risk and heterogeneity (Q and I2 index). A total of 168 original studies met the inclusion criteria with 90,688 prostate cancer cases. Significantly increased risks were observed for the following occupational exposures: pesticides (metaRR = 1.15, 95% confidence interval [CI] = 1.01-1.32; I2 = 84%), and specifically group of organochlorine pesticides (meta relative risk [metaRR] = 1.08, 95% CI = 1.03-1.14; I2 = 0%), chromium (metaRR = 1.19, 95% CI = 1.07-1.34; I2 = 31%), shift work (metaRR = 1.25, 95% CI = 1.05-1.49; I2 = 78%) and pilots (metaRR = 1.41, 95% CI = 1.02-1.94; I2 = 63%) and occupational physical activity in cohort studies (metaRR = 0.87, 95% CI = 0.81-0.94; I2 = 0%). The literature review supports a causal association for a few of the previously suggested factors.

The Effect of Hexavalent Chromium on the Incidence and Mortality of Human Cancers: A Meta-Analysis Based on Published Epidemiological Cohort Studies

Background: Hexavalent chromium [Cr(VI)] is an occupational carcinogen that can cause lung and nasal cancers, but its association with mortality and incidence in many other cancers is unclear.

Objectives: In this meta-analysis, we aimed to evaluate the relationship between exposure to Cr(VI) and the mortality and incidence of human cancers.

Methods: We performed a search of the literature and extracted the standardized mortality ratios (SMRs), standardized incidence ratios (SIRs), and their corresponding 95% confidence intervals (CIs), to estimate risk values. Subgroup analyses were conducted by sex, occupation, and types of cancer to identify groups that were at high-risk or predisposed to certain cancers.

Results: A total of 47 cohort studies covering the period 1985–2016 were included (37 studies reporting SMRs and 16 studies reporting SIRs). The summary SMR for all studies combined was 1.07 (95% CI: 1.01–1.15). Summary SMRs were higher among chromate production workers, chrome platers, and masons, and especially male workers. In the subgroup analysis, Cr(VI) exposure was related to a higher risk of death owing to lung, larynx, bladder, kidney, testicular, bone, and thyroid cancer. The meta-SIR of all studies combined was 1.06 (95% CI: 1.04–1.09). Summary SIRs were elevated among cement industry workers and tanners. Cr(VI) exposure was related to an elevated risk of respiratory system, buccal cavity, pharynx, prostate, and stomach cancers.

Conclusions: Cr(VI) might cause cancers of the respiratory system, buccal cavity and pharynx, prostate, and stomach in humans, and it is related to increased risk of overall mortality owing to lung, larynx, bladder, kidney, testicular, bone, and thyroid cancer. In addition, there was a strong association between incidence and mortality risk of cancers and concentration of Cr(VI) in the air and the exposure time.

Prostate cancer characteristics in the World Trade Center cohort, 2002-2013

An increased incidence of prostate cancer was reported in three cohorts of World Trade Center (WTC) respondents. It is uncertain whether this increase is because of WTC-related exposures or enhanced surveillance. Prostate cancer cases (2002-2013) were obtained from the WTC Health Program. Age, race, and Gleason score distribution were compared with New York State Cancer Registry cases from the same time period. Multivariate models were adjusted for age and race. Analyses of clinical characteristics of prostate cancer cases within the cohort were also carried out, adjusting for age, race, and WTC exposure categories. WTC respondents had a prostate cancer age-standardized rate ratio of 1.65 [95% confidence interval (CI): 1.37-1.93] compared with New York State; age-specific ratios were highest for ages 30-49 (2.28; 95% CI: 1.51-3.43), 70-74 (2.05; 95% CI: 1.03-4.10), and 80-84 years (5.65; 95% CI: 1.41-22.58). High WTC exposure was associated with advanced clinical stage (5.58; 95% CI: 1.05-29.76; Ptrend=0.03). WTC respondents continue to have a higher prostate cancer rate compared with New York State as a whole. Respondents with a higher WTC exposure level may have had more advanced clinical stage of prostate cancer.

Computer-automated silica aerosol generator and animal inhalation exposure system

Inhalation exposure systems are necessary tools for determining the dose response relationship of inhaled toxicants under a variety of exposure conditions. The objective of this study was to develop an automated computer controlled system to expose small laboratory animals to precise concentrations of uniformly dispersed airborne silica particles. An acoustical aerosol generator was developed which was capable of re-suspending particles from bulk powder. The aerosolized silica output from the generator was introduced into the throat of a venturi tube. The turbulent high-velocity air stream within the venturi tube increased the dispersion of the re-suspended powder. That aerosol was then used to expose small laboratory animals to constant aerosol concentrations, up to 20 mg/m(3), for durations lasting up to 8 h. Particle distribution and morphology of the silica aerosol delivered to the exposure chamber were characterized to verify that a fully dispersed and respirable aerosol was being produced. The inhalation exposure system utilized a combination of airflow controllers, particle monitors, data acquisition devices and custom software with automatic feedback control to achieve constant and repeatable exposure environments. The automatic control algorithm was capable of maintaining median aerosol concentrations to within ±0.2 mg/m(3) of a user selected target concentration during exposures lasting from 2 to 8 h. The system was able to reach 95% of the desired target value in <10 min during the beginning phase of an exposure. This exposure system provided a highly automated tool for conducting inhalation toxicology studies involving silica particles.

Heavy and light/moderate smoking among building trades construction workers

OBJECTIVE

The purpose of the study was to identify the correlates of heavy smoking (defined as more than one pack of cigarettes per day) in building trades construction workers.

DESIGN AND SAMPLE

This study used cross-sectional data from the MassBUILT smoking cessation intervention study at Massachusetts building trades unions with the sample of 763 smokers.

MEASURES

Data collected included information about smoking behavior, individual, psychological, interpersonal, and occupational factors obtained through self-reported questionnaires.

RESULTS

Approximately 21% of smokers were heavy smokers. Significant factors related to heavy smoking were: older age (OR = 1.10; 95% CI: 1.06-1.14), male gender (OR = 4.55; 95% CI: 1.62-12.79), smoking the first cigarette of the day within 30 min of waking (OR = 4.62; 95% CI: 2.81-7.59), smoking initiation at earlier age (OR = 0.93; 95% CI: 0.87-1.00), higher temptation to smoke (OR = 1.55; 95% CI: 1.17-2.05), household smoking (OR = 1.90; 95% CI: 1.18-3.06) or living alone (OR = 4.11; 95% CI: 1.70-9.92), and exposure to chemicals at work (OR = 1.61; 95% CI: 1.06-2.53).

CONCLUSION

Addressing the influence of these factors on heavy smoking could lead to the development of targeted, multiple components in comprehensive cessation strategies for blue-collar smokers.

Dust exposure and the risk of cancer in cement industry workers in Korea

BACKGROUND

Cement is used widely in the construction industry, though it contains hazardous chemicals such as hexavalent chromium. Several epidemiological studies have examined the association between cement dust exposure and cancer, but these associations have proved inconclusive. In the present study, we examined the association between dust exposure and cancer in cement industry workers in Korea.

METHODS

Our cohort consisted of 1,324 men who worked at two Portland cement manufacturing factories between 1997 and 2005. We calculated cumulative dust exposures, then categorized workers into high and low dust exposure groups. Cancer cases were identified between 1997 and 2005 by linking with the national cancer registry. Standardized incidence ratios (SIRs) were calculated for all workers and the high and low dust exposure groups, respectively.

RESULTS

The SIR for overall cancers in all workers was increased (1.35, 95% CI: 1.01-1.78). The SIR for stomach cancer in the high dust exposure group was increased (2.18, 95% CI: 1.19-3.65), but there was no increased stomach cancer risk in the low dust exposure group. The SIR for rectal cancer in all workers was increased (3.05, 95% CI: 1.32-6.02). Rectal cancer risk was similar in the high and low exposure groups.

CONCLUSIONS

Our findings suggest a potential association between exposure in the cement industry and an increased risk of stomach and rectal cancers. However, due to the small number of cases, this association should be further investigated in a study with a longer follow-up period and adjustment for confounders.

Airborne exposures and risk of gastric cancer: A prospective cohort study

There is an unexplained male predominance among patients with gastric cancer, and many carcinogens are found in male-dominated dusty occupations. However, the relation between occupational exposures and risk of gastric cancer remains unclear. To investigate whether airborne occupational exposures might influence the risk of noncardia gastric cancer, we used a large, prospective cohort study of male Swedish construction workers. These workers were, during the period 1971-1993, regularly invited to health examinations by a nationwide occupational health service organization. Data on job titles and other variables were collected through self-administered questionnaires and forms completed by the health organization's staff. Industrial hygienists assessed 12 specific airborne occupational exposures for 200 job titles. Gastric cancer, death or emigration occurring during follow-up in 1971-2002 were identified by linkage to the Swedish registers of Cancer, Causes of Death and Total Population, respectively. Incidence rate ratios (IRR) and 95% confidence intervals (CI), adjusted for attained age, tobacco smoking, calendar period and body mass, were derived from Cox regression. Among 256,357 cohort members, contributing 5,378,012 person-years at risk, 948 noncardia gastric cancers were identified. Increased risk of this tumor was found among workers exposed to cement dust (IRR 1.5 [95% CI 1.1-2.1]), quartz dust (IRR 1.3 [95% CI 1.0-1.7]) and diesel exhaust (IRR 1.4 [95% CI 1.1-1.9]). Dose-response relations were observed for these exposures. No consistent positive associations were found regarding exposure to asbestos, asphalt fumes, concrete dust, epoxy resins, isocyanates, metal fumes, mineral fibers, organic solvents or wood dust. In conclusion, this study provides some support to the hypothesis that specific airborne exposures increase the risk of noncardia gastric cancer.

Occupational exposure to crystalline silica dust in the United States, 1988-2003

The purposes of this study were a) to summarize measurements of airborne (respirable) crystalline silica dust exposure levels among U.S. workers, b) to provide an update of the 1990 Stewart and Rice report on airborne silica exposure levels in high-risk industries and occupations with data for the time period 1988-2003, c) to estimate the number of workers potentially exposed to silica in industries that the Occupational Safety and Health Administration (OSHA) inspected for high exposure levels, and d) to conduct time trend analyses on airborne silica dust exposure levels for time-weighted average (TWA) measurements. Compliance inspection data that were taken from the OSHA Integrated Management Information System (IMIS) for 1988-2003 (n = 7,209) were used to measure the airborne crystalline silica dust exposure levels among U.S. workers. A second-order autoregressive model was applied to assess the change in the mean silica exposure measurements over time. The overall geometric mean of silica exposure levels for 8-hr personal TWA samples collected during programmed inspections was 0.077 mg/m3, well above the applicable American Conference of Governmental Industrial Hygienists threshold limit value of 0.05 mg/m3. Surgical appliances supplies industry [Standard Industrial Classification (SIC) 3842] had the lowest geometric mean silica exposure level of 0.017 mg/m3, compared with the highest level, 0.166 mg/m3, for the metal valves and pipe fitting industry (SIC 3494), for an 8-hr TWA measurement. Although a downward trend in the airborne silica exposure levels was observed during 1988-2003, the results showed that 3.6% of the sampled workers were exposed above the OSHA-calculated permissible exposure limit.

Mortality and cancer incidence among Lithuanian cement producing workers

AIMS

To investigate mortality and cancer incidence of cement producing workers.

METHODS

A total of 2498 cement workers who have been employed at Portland cement producing departments for at least one year from 1956 to 2000 were followed up from 1 January 1978 to 31 December 2000. The cohort contributed 43,490 person-years to the study. Standardised incidence ratios (SIR) and standardised mortality ratios (SMR) were calculated as ratios between observed and expected numbers of cancers and deaths. The expected numbers were based on sex specific incidence and mortality rates for the total Lithuanian population.

RESULTS

Significantly increased SMRs were found for all malignant neoplasms (SMR 1.3, 95% CI 1.0 to 1.5) and for lung cancer (SMR 1.4, 95% CI 1.0 to 1.9) among male cement workers. SIR for all cancer sites was 1.2 (95% CI 1.0 to 1.4). Excess risk was found for cancer of the lung (SIR 1.5, 95% CI 1.1 to 2.1). The SIR for urinary bladder cancer was also increased (SIR 1.8, 95% CI 0.9 to 3.5). The overall cancer incidence was not increased among females (SIR 0.8, 95% CI 0.6 to 1.1). With increasing cumulated exposure to cement dust, there were indications of an increasing risk of lung and stomach cancers among males.

CONCLUSIONS

This study supported the hypothesis that exposure to cement dust may increase the lung and bladder cancer risk. A dose related risk was found for stomach cancer, but no support was found for an increased risk of colorectal cancer.

Epidemiology of lymphomas

Non-Hodgkin lymphoma (NHL) is the fifth most common cancer in the US, with about 55,000 new cases estimated for the year 2000. According to the new Surveillance, Epidemiology, and End Results (SEER) data from 1973 to 1997, the age-adjusted incidence rates rose by about 80%, with an annual percentage increase of nearly 3%, which is faster than for the majority of cancers. The increasing incidence of NHL is largely unexplained. AIDS-related NHL accounts for some but not all of the increase. The American Cancer Society predicts about 7,400 new cases of Hodgkin Disease (HD) in the year 2000 in the US. The incidence of HD is consistently lower than that of NHL, and has decreased about 16% since the 1970s. Only a small portion of the decrease in HD incidence can be explained by misdiagnosis of HD as NHL. Further research is needed on the cofactors that predispose AIDS cases to lymphoma, as well as other possible causes of NHL such as immunosuppression, genetics, viruses, medical conditions, pesticides, solvents, hair dyes, and diet. Further evaluation of the role of viruses, occupational exposures, and genetics in the etiology of HD should prove valuable.