Excess lung cancer occurrence in poultry plants. Occupational risk factors: Findings for oncogenic viruses exposure and other occupational exposures.

Certain viruses naturally infect and cause cancer in chickens and turkeys. Humans are widely exposed. The viruses cause cancer in primates, and transform human cells in vitro, but it is not known if they cause cancer in humans, mainly because of the lack of epidemiologic evidence. We conducted cohort mortality studies of workers in poultry slaughtering/processing plants across the United States, because they have the highest human exposures. An excess of lung cancer and other deaths was recorded in the poultry workers. Here, we report on a case-cohort study of the lung cancer deaths nested within these cohorts, that was conducted to provide epidemiologic evidence linking these viruses with human cancer occurrence, while adjusting for possible confounders, including workplace chemical carcinogens. We obtained interviews for 339 lung cancer deaths and 457 controls, selected from our combined cohorts of 30,411 poultry plant workers and 16,405 non-poultry workers, belonging to United Food & Commercial Workers unions. Data was analyzed by both logistic regression and Cox regression, adjusting for smoking and other confounders. Lung cancer risk was independently associated with tasks or work areas indicative of exposure to both poultry oncogenic viruses and to workplace chemical carcinogens. The study provides an incremental piece of evidence (epidemiologic), indirectly linking the oncogenic viruses of poultry with the occurrence of cancer in humans, and thus may have public health implications, but the limitations highlighted must be considered. Confirmatory studies, particularly molecular studies providing definitive proof of poultry oncogenic retrovirus integration in human DNA are needed, before the findings observed in this study can be put into proper perspective.

Investigation of cancer mortality inequalities between rural and urban areas in South Korea.

OBJECTIVE: Little is known about rural-urban cancer disparities, particularly in South Korea, and this study is to identify cancer-specific mortality inequalities between the rural and urban areas of the country. DESIGN, SETTING, AND PARTICIPANTS: For 11 specific cancer sites, age-standardised mortality rates were analysed for the rural and urban administrative districts of South Korea during 2006-2011. MAIN OUTCOME MEASURES: The Poisson log linear regression models were employed to estimate cancer-specific mortality rates, and Bonferroni comparison method was used to identify rural-urban disparities. RESULTS: There were significant rural-urban disparities observed for all cancer sites except prostate, pancreas and leukaemia. The mortality rates of lung, liver and stomach cancers, the three most common cancers in the country, were observed to be significantly higher in rural areas than in metropolitan areas. In contrast, the reverse relationship was observed for the reproductive system (breast and uterus) and colon cancers. Central nervous system cancer mortality was observed to be significantly higher in rural areas than in non-metro urban areas. CONCLUSIONS: For the first time ever, significant rural-urban disparity patterns in cancer mortality rates in South Korea have been identified in this paper. Future investigations on cancer risk factors for the country should address these disparity patterns.

Mortality in workers employed in pig abattoirs and processing plants.

OBJECTIVE: workers in slaughterhouses and processing plants that handle pigs, and pork butchers/meatcutters have been little studied for health risks associated with employment, in spite of the fact that they are potentially exposed to oncogenic and non-oncogenic transmissible agents and chemical carcinogens at work. We report here on an update of mortality in 510 workers employed in abattoirs and processing plants that almost exclusively handled pigs and pork products. METHODS: standardized mortality ratios (SMRs) were estimated for the cohort as a whole, and in subgroups defined by race and sex, using the corresponding US general population mortality rates for comparison. Study subjects were followed up from January 1950 to December 2006, during which time 45% of them died. RESULTS: mortality was significantly increased overall in the cohort. A statistically significant excess of deaths was observed for colon and lung cancers in the entire cohort, SMR=2.7 (95% CI, 1.2-5.1), SMR=1.8 (95% CI, 1.1-2.7), respectively. Significant SMRs in the cohort as a whole were also observed for senile and pre-senile psychotic conditions (SMR=5.1, 95% CI, 1.4-13.1), and pneumonia (SMR=2.6, 95% CI, 1.3-4.8). An observed excess of subarachnoid hemorrhage was seen mainly in whites (SMR=10.1, 95% CI, 1.2-36.3). There was a suggestion of an excess of deaths from ischemic heart disease also, but the elevated SMR was confined to men and was not statistically significant. CONCLUSION: this study confirms the excess occurrence of lung and colon cancers, and stroke previously reported in this occupational group. New findings are the excess of risk for senile and pre-senile psychotic conditions and pneumonia, which together with the excess of colon cancer appear specific for pig/pork workers, as they were not evident in much larger studies of workers in abattoirs and processing plants handling cattle and sheep. However, caution should be exercised in interpreting these findings, since some of them could have occurred by chance, resulting from our examination of a large number of causes of death in multiple study subgroups. For the moment, the significance of these findings remains unknown until they are confirmed in larger studies of adequate statistical power. Studies that will take into account possible occupational and non-occupational confounding factors are needed.

Cancer and noncancer mortality among American seafood workers.

BACKGROUND: Few studies have investigated mortality in seafood workers worldwide, and no such study has been conducted in the United States. The objective of this study was to investigate mortality in American seafood workers. METHODS: The study population was derived from 4 states and consisted of 4116 subjects who worked mainly in seafood processing plants. They were followed up from 1966 to 2003. Standardized mortality ratios (SMRs) and proportional mortality ratios (PMRs) were estimated, using the US general population for comparison. RESULTS: About 45% of the cohort was born after 1949. A total of 788 deaths were recorded; 53% of the decedents were female, and 88% were white. The SMRs for stomach cancer and disorders of the thyroid gland in the cohort as a whole were 2.1 (95% confidence interval [CI], 1.1-3.8) and 6.1 (95% CI 1.3-18.0), respectively. The SMRs for breast cancer, and occlusion/stenosis of the pre-cerebral/cerebral arteries in the cohort as a whole were 0.5 (95% CI, 0.3-0.9) and 0.5 (95% CI, 0.2-0.8), respectively. The SMR for ischemic heart disease in white females was 0.8 (95% CI, 0.6-0.9). CONCLUSIONS: This cohort had excess deaths from stomach cancer and disorders of the thyroid gland, and deficit of deaths from breast cancer, stroke and ischemic heart disease. The significance of these findings is unknown, especially as less than 20% of the cohort were deceased. Nevertheless, the cohort is unique and important, and further follow-up may shed more light on mortality patterns in this occupational group.

Industrial hygiene assessment of reticuloendotheliosis viruses exposure in the poultry industry.

OBJECTIVES: Reticuloendotheliosis viruses (REV) are a group of retroviruses like avian leukosis/sarcoma viruses (ALSV) that naturally infect and cause cancers in chickens. We recently found that ALSV antibody levels were associated with job tasks in the poultry industry. The objectives of this study are to examine whether a similar association can be found with REV antibody levels and to examine the correlation between REV and ALSV antibody levels. METHODS: Relative risk was estimated comparing REV antibody levels of 45 poultry workers with those of 44 controls. The expected mean antibody level was predicted for the association with employment by a generalized linear model. Correlation coefficient was measured between ALSV and REV antibody levels. RESULTS: REV antibody levels were significantly higher in poultry workers than in control subjects and were associated with gender and employment conditions, especially employment duration. The relative risk was significantly higher for some job categories. A significant correlation was observed between REV and ALSV antibody levels, which was strong among poultry workers, but weak among the control subjects. CONCLUSION: Antibody levels can be validly used to identify certain job tasks associated with high risk of exposure to REV in the workplace, and the practical implication is recommendations for protection at these job tasks. Importantly, in situations where there is exposure to multiple pathogens in the workplace, the analysis of antibody levels of one pathogen may sufficiently represent exposure to the other correlated pathogens. This suggested exposure assessment may hold true for pathogens with a similar route of transmission.

Occupational exposure assessment using antibody levels: exposure to avian leukosis/sarcoma viruses in the poultry industry.

Avian leukosis/sarcoma viruses (ALSV) infect and cause cancers in chickens. Poultry workers are exposed to ALSV and other infectious agents in the workplace. This study examines if industrial hygiene assessment of antibody levels in poultry workers can identify risky job tasks at the higher exposure risk to an infectious agent, i.e., ALSV. We compared ALSV antibody levels in poultry workers and control subjects. Occupational and demographical factors were examined for an association with the exposure risk in poultry workers. We found that the antibody levels were significantly higher in poultry workers than in control subjects. Job category and age together were significantly associated with the antibody levels in workers. Certain job tasks were identified with significantly higher antibody levels as compared to others, implying that recommendations should be made to protect workers at these jobs. The findings of this study indicate that the measurement of antibody levels in workers can be useful for industrial hygiene assessment of exposure to infectious agents.

The association between irritable bowel syndrome and the coexistence of depression and insomnia.

OBJECTIVE: The individual occurrence of depression or insomnia is a risk factor for irritable bowel syndrome (IBS), but few researchers have evaluated the association between comorbid depression and insomnia and IBS. The aim of the present study is to explore the relationship between IBS and the coexistence of depression and insomnia in a Korean population-based cohort study. METHODS: A total of 3429 individuals who were enrolled in the Korean Genome and Epidemiology Study were analysed. Of the participants, 10.9% (n=374) were diagnosed with IBS based on the Rome II criteria. Regarding depressive symptoms, subjects were sub-divided into three groups based on the Beck Depression Inventory (BDI) score. Insomnia was defined as a positive response to at least one of three questions on sleep states. RESULTS: The odds ratio (OR) of IBS increased proportionally as depressive symptoms worsened (OR: 1.64; 95% CI: 1.21-2.23 in middle tertile and OR: 2.61; 95% CI: 1.92-3.55 in highest tertile). Subjects with insomnia showed a higher OR of IBS than those without insomnia (OR: 1.81; 95% CI: 1.44-2.27). In the joint analysis of BDI and insomnia, the odds for IBS were significantly higher in all BDI tertiles with insomnia than in the corresponding BDI tertiles without insomnia. There was no significant interaction effect of BDI tertile and insomnia on IBS. CONCLUSION: The presence of both depression and insomnia is significantly associated with IBS compared to each individual occurrence. Further prospective investigations are needed to explore possible causality between comorbid depression and insomnia and IBS.

Concurrent presence of inflammation and obstructive sleep apnea exacerbates the risk of metabolic syndrome: A KoGES 6-year follow-up study.

Obstructive sleep apnea (OSA) leads to multiple end-organ morbidities that are mediated by the cumulative burden of oxidative stress and inflammation. Both OSA and inflammation play key roles in increased risk of cardiovascular disease (CVD). Thus, we hypothesized that the combination of inflammation and OSA could accelerate the development of metabolic syndrome (MetS) in a large cohort study.A total of 1835 participants were randomly selected from the ongoing Korean Genome and Epidemiology Study for the years between 2007 and 2015. Overnight polysomnography was performed on each participant. Blood was drawn for biochemical analyses. Participants with high or low inflammation were divided by high-sensitivity C-reactive protein (hsCRP). MetS was defined using the criteria of the modified National Cholesterol Education Program, Adult Treatment Panel III.The prevalence of MetS was higher among the subjects with OSA and high hsCRP levels than among the other corresponding groups. The incidence of MetS among the 4 groups stratified by OSA and inflammation status at the 6-year follow-up was 11.8%, 19.9%, 25.8%, and 36.0% (HsCRP[-]/OSA[-] vs HsCRP[+]/OSA[-] vs HsCRP[-]/OSA[+] vs HsCRP[+]/OSA[+], P < 0.01). After adjusting for age, sex, smoking, alcohol status, BMI, and change in BMI (ΔBMI) in a multiple logistic regression, the subjects with OSA and high hsCRP levels at follow-up had a 2.22-fold risk of developing MetS, as compared with those with no-OSA and low hsCRP levels (P < 0.01).MetS is more prevalent in the concurrent presence of inflammation and OSA. The combination of these conditions is associated with higher risk of MetS. Additional research is needed to help further define the significance of the combined effect of OSA and subclinical inflammation on the development of MetS in the context of reduction of CVD risk.

Overlap syndrome of COPD and OSA in Koreans.

Overlap syndrome of chronic obstructive pulmonary disease (COPD) and obstructive sleep apnea (OSA) leads to increased morbidity and mortality. There have been no reports available on the overlap syndrome for Koreans. Our primary aim was to identify prevalence and predictors of the overlap syndrome in Koreans.This is a cross-sectional study with a community-based sample of 1298 participants (mean age, 59.7 ±â€Š6.7) from the cohort of Korean Genomic and Epidemiologic Study during 2013 to 2014. OSA and COPD were assessed by apnea-hypopnea index (AHI) and the ratio of forced expiratory volume in 1 s to forced vital capacity (FEV1/FVC < 70%), respectively, based on polysomnography and spirometry measurements. Using logistic regression with adjustment for the confounders identified by univariate analysis, odds ratio (OR) was estimated with 95% confidence interval (CI) of COPD among those with OSA.The prevalence rate of OSA was 45.8%, of which 32.8% were moderate-to-severe (AHI ≥ 15); 10.8% of those having OSA also had COPD, that is, the overlap syndrome. The prevalence of COPD remained the same as 10.8% regardless of the presence of OSA. The mean ratio of FEV1/FVC for those with COPD was 0.77, regardless of OSA. The OR increased for age (OR, 1.1; 95% CI, 1.0-1.1) and smokers (OR, 3.6; 95% CI, 2.0-6.4), but decreased for body mass index (BMI) (OR, 0.84; 95% CI, 0.8-0.9) and overweight state (OR, 0.4; 95% CI, 0.2-0.7). Risk factors of the overlap syndrome differed by OSA severity, that is, BMI in those with moderate-to-severe OSA, whereas sex (OR, 4.7; 95% CI, 2.1-10.6) and age (OR, 1.1; 95% CI, 1.0-1.1) in those with mild OSA.In a population study from Korea, 10.8% of OSA patients had an overlap syndrome with COPD. Although BMI is a well-known risk factor of OSA, it is likely that being overweight may be protective for moderate-to-severe OSA patients from the risk of COPD (i.e., overlap syndrome).

Interaction between Obstructive Sleep Apnea and Shortened Telomere Length on Brain White Matter Abnormality.

STUDY OBJECTIVES: Age-related brain white matter changes (WMC) have been associated separately with obstructive sleep apnea (OSA) and short telomere length (TL). No studies have examined their interaction effect on WMC. METHODS: This is a cross-sectional study with a community-based sample of 420 participants (mean age, 61.3 ± 7.2) from the Korean Genome and Epidemiology Study during 2011-2012. An overnight fasted blood sample was taken to determine glucose and blood lipid levels at the sleep laboratory of Korea University Ansan Hospital. The status of brain WMC was determined using structural magnetic resonance imaging at 1.5 Tesla. Overnight polysomnography was performed, and leukocyte TL was measured. OSA was determined based on apnea-hypopnea index, and short TL was defined as the lowest quartile of the study participants. RESULTS: Adjusting for age, sex, BMI, smoking, drinking, snoring, and hypertension, odds ratio (OR) of brain WMC was estimated using multivariate logistic regression. The odds ratio was significant for cardiovascular disease (OR, 4.5; 95% CI, 1.2-16.3) and OSA (OR, 4.0; 95% CI, 1.0-15.2) among those with short TL; and for diabetes (OR, 3.0; 95% CI, 1.3-13.0) and age (OR, 1.1; 95% CI, 1.0-1.1) among those with longer TL. Interaction effect of OSA and short TL (OR, 4.3; 95% CI, 1.4-13.8) was significant, compared to those with neither OSA nor short TL. CONCLUSIONS: This study provides a first evidence of mediated interaction of short TL with OSA on brain WMC in a community-based sample. The results generate new hypotheses regarding mechanisms of impaired brain health in sleep apnea.

Obstructive Sleep Apnea Is Associated with Elevated High Sensitivity C-Reactive Protein Levels Independent of Obesity: Korean Genome and Epidemiology Study.

Obstructive sleep apnea syndrome (OSA) has been recognized as a common health problem, and increasing obesity rates have led to further remarkable increases in the prevalence of OSA, along with more prominent cardiovascular morbidities. Though previous studies have reported an independent relationship between elevated high sensitivity C-reactive protein (hsCRP) levels and OSA, the issue remains controversial owing to inadequate consideration of obesity and various confounding factors. So far, few population based studies of association between OSA and hsCRP levels have been published. Therefore, the purpose of the present study was to investigate whether OSA is associated with increased hsCRP levels independent of obesity in a large population-based study. A total of 1,835 subjects (968 men and 867 women) were selected from a larger cohort of the ongoing Korean Genome and Epidemiology Study (KoGES). Overnight polysomnography was performed on each participant. All participants underwent anthropometric measurements and biochemical analyses, including analysis of lipid profiles and hsCRP levels. Based on anthropometric data, body mass index (BMI) and waist hip ratio (WHR) were calculated and fat mass (FM) were measured by means of multi-frequency bioelectrical impedance analysis (BIA). Mild OSA and moderate to severe OSA were defined by an AHI >5 and ≥15, respectively. The population was sub-divided into 3 groups based on the tertile cut-points for the distribution of hsCRP levels. The percentage of participants in the highest tertile of hsCRP increased dose-dependently according to the severity of OSA. After adjustment for potential confounders and obesity-related variables (BMI, WHR, and body fat) in a multiple logistic model, participants with moderate to severe OSA had 1.73-, 2.01-, and 1.61-fold greater risks of being in the highest tertile of hsCRP levels than participants with non-OSA, respectively. Interaction between obesity (BMI ≥25kg/m2) and the presence of moderate-to-severe OSA was significant on the middle tertile levels of hsCRP (OR = 2.4), but not on the highest tertile, compared to the lowest tertile. OSA is independently associated with elevated hsCRP levels and may reflect an increased risk for cardiovascular morbidity. However, we found that OSA and obesity interactively contribute to individuals with general levels of hsCRP (<1.01 mg/dl). The short-term and long-term effects of elevated hsCRP levels on cardiovascular risk in the context of OSA remain to be defined in future studies.

Association of Sasang Constitutional Type with Sarcopenia.

Sasang constitutional medicine (SCM) is a unique Korean traditional medicine that classifies human beings as four distinct types named Sasang constitutional types (SCTs), based on physiologic, physical, and psychological traits. Accumulating evidence has demonstrated that specific constitutional types are associated with chronic diseases, but no study has investigated the relationship between SCTs and sarcopenia. The aim of this study was to examine the association in a large population-based study. Data from 1,204 participants who completed questionnaires for life style, anthropometric evaluation, and biochemical analysis were analyzed. Classification of the SCTs was done using an integrated diagnostic method. Sarcopenia was defined as appendicular skeletal muscle mass/height(2) less than one standard deviation below the gender-specific normal mean of a younger group. Dual-energy X-ray absorptiometry was used to assess whole body composition. The prevalence of sarcopenia was 8.6% in the Tae-eum (TE) type, 44.7% in the So-eum (SE) type, and 20.7% in the So-yang (SY) type. Multivariate analysis revealed that the SE and SY types had 9.22 (5.06-16.81; P < 0.0001) and 2.90 (1.76-4.76; P < 0.0001) greater odds of sarcopenia compared to the TE type, respectively. Our results show that the SE and SY types are significantly associated with increased prevalence of sarcopenia.

Efficient mapping of California mortality fields at different spatial scales.

A meaningful characterization of epidemiologic fields (mortality, incidence rate, etc.) often involves the assessment of their spatiotemporal variation at multiple scales. An adequate analysis should depend on the scale at which the epidemiologic field is considered rather than being limited by the scale at which the data are available. In many studies, for example, data are available at a larger scale (say, counties), whereas the epidemiologist is interested in a smaller-scale analysis (say, residential neighborhoods). We propose a mathematically rigorous and epidemiologically meaningful multiscale approach that uses the well-known BME theory to study important scale effects and generate informative scale-dependent maps. The approach is applied to a real-world case study involving daily mortality counts in the state of California. The approach accounts for scale effects and produces mortality predictions at the zip-code scale by downscaling data from the county scale. The multiscale approach is tested by means of a verification data set with detailed mortality information at the zip-code level for 1 day. A measure of mapping accuracy is used to demonstrate that the multiscale approach offers more accurate mortality predictions at the local scale than existing approaches, which do not account for scale effects.

Distribution of the Immunoreactivity for Glycoprotein M6B in the Neurogenic Niche and Reactive Glia in the Injury Penumbra Following Traumatic Brain Injury in Mice.

The location and morphology of astrocytes are known to contribute to their diversity, and this diversity is often associated with their selective functions. However, molecular markers for astrocyte subtypes are largely unknown. In this study, we found that the immunoreactivity for glycoprotein GPM6B (M6B-IR) is preferentially expressed in the astrocytes associated with ventricles or neurogenic regions of the adult mouse brain. In particular, M6B-IR in the neurogenic niche was confined to glial fibrillary acidic protein- or nestin-expressing neural stem cells. Furthermore, in the injury penumbra, reactive astrocytes expressing nestin also exhibited strong M6B-IR. These results reveal that GPM6B is a potential molecular marker for a subset of astrocytes, as well as for the injury-dependent activation of astrocytes.

A cohort mortality study of workers in a soup manufacturing plant.

There has been no study of disease risk or exposures in workers in soup manufacturing plants. These workers may have hazardous exposures to biological and chemical cancer-causing agents at the workplace. The authors report here on mortality in 1,779 workers from a plant in Baltimore, Maryland. Standardized mortality ratios (SMRs) were estimated using the US population for comparison. Significantly increased mortality was observed for cancer of the floor of the mouth, colon cancer, epilepsy, and chronic nephritis in certain groups. Significantly decreased SMRs were observed for some causes. The findings are important, given the complete absence of data on this occupational group. It is not known whether the associations observed are related to occupational or nonoccupational exposures, or due to chance. The findings do, however, indicate that further studies of this occupational group are warranted.