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The Cox proportional hazard model may predict whether an individual belonging to a given group would likely register an event of interest at a given time. However, the Cox model is limited by relatively strict statistical assumptions. In this study, we propose decomposing the time-to-event variable into “time” and “event” components and using the latter as a target variable for various machine-learning classification algorithms, which are almost assumption-free, unlike the Cox model. While the time component is continuous and is used as one of the covariates, i.e., input variables for various classification algorithms such as logistic regression, naïve Bayes classifiers, decision trees, random forests, and artificial neural networks, the event component is binary and thus may be modeled using these classification algorithms. Moreover, we apply the proposed method to predict a decrease or non-decrease of IgG and IgM blood antibodies against COVID-19 (SARS-CoV-2), respectively, below a laboratory cut-off, for a given individual at a given time point. Using train-test splitting of the COVID-19 dataset (n=663 individuals), models for the mentioned algorithms, including the Cox proportional hazard model, are learned and built on the train subsets while tested on the test ones. To increase robustness of the model performance evaluation, models’ predictive accuracies are estimated using 10-fold cross-validation on the split dataset. Even though the time-to-event variable decomposition might ignore the effect of individual data censoring, many algorithms show similar or even higher predictive accuracy compared to the traditional Cox proportional hazard model. In COVID-19 IgG decrease prediction, multivariate logistic regression (of accuracy 0.811), support vector machines (of accuracy 0.845), random forests (of accuracy 0.836), artificial neural networks (of accuracy 0.806) outperform the Cox proportional hazard model (of accuracy 0.796), while in COVID-19 IgM antibody decrease prediction, neither Cox regression nor other algorithms perform well (best accuracy is 0.627 for Cox regression). An accurate prediction of mainly COVID-19 IgG antibody decrease can help the healthcare system manage, with no need for extensive blood testing, to identify individuals, for instance, who could postpone boosting vaccination if new COVID-19 variant incomes or should be flagged as high risk due to low COVID-19 antibodies.

Background and Objectives: Given the limited knowledge of antibody responses to COVID-19 and their determinants, we analyzed the relationship between the occurrence of acute-phase symptoms and infection-induced immunoglobulin (Ig) G seropositivity up to 8 months post-symptom onset. Materials and Methods: In this cross-sectional study, 661 middle-aged unvaccinated healthcare workers (HCWs) were interviewed about the presence of symptoms during the acute phase of their previously confirmed COVID-19 and were tested for specific IgG, targeting the spike protein (S1 and S2). The dependence of seropositivity on the symptom occurrence was explored through multiple logistic regression, adjusted for the interval between symptom onset and serology testing, and through classification and regression trees. Results: A total of 551 (83.4%) HCWs showed seropositivity and, inversely, 110 (16.6%) HCWs were seronegative. The chance of IgG seropositivity was increased by dyspnea (odds ratio (OR) 1.48, p < 0.001) and anosmia (OR 1.52, p = 0.021). Fever in HCWs with dyspnea resulted in the highest detected seropositivity rate, and anosmia in HCWs without dyspnea significantly increased the proportion of seropositivity. Conclusion: Clinical manifestation of the acute phase of COVID-19 predisposes to the development of infection-induced antibody responses. The findings can be applied for assessing the long-term protection by IgG, and thus, for creating effective surveillance strategies.

High vaccination coverage among healthcare workers (HCWs) is crucial for managing the COVID-19 pandemic. The aim was to determine the demand for vaccination among all employees (n = 4553) of a tertiary care hospital after several weeks of the vaccine’s availability, and to analyze motives for acceptance and reasons for hesitancy through an anonymous online questionnaire. Upon the completion of data collection, the hospital’s vaccination coverage was at 69.8%. A total of 3550 completed questionnaires were obtained (2657 from vaccinated, 893 from unvaccinated employees). Significant predictors of vaccine acceptance were: age (odds ratio (OR) 1.01, 95% confidence interval (CI) 1.01–1.02), sex (OR (females) 0.58, 95% CI 0.45–0.75), job type (OR (non-physician HCWs) 0.54, 95% CI 0.41–0.72; OR (non-HCWs) 0.51, 95% CI 0.37–0.71), fear of COVID-19 (OR 1.4, 95% CI 1.34–1.46), history of COVID-19 (OR 0.41, 95% CI 0.34–0.49) and of influenza vaccination (OR 2.74, 95% CI 2.12–3.57). The most frequent motive for acceptance was the effort to protect family members (84%), while concerns about vaccine safety and side effects (49.4%), followed by distrust in the vaccine’s efficacy (41.1%) were the top reasons for hesitancy. To increase vaccination coverage among HCWs, it is necessary to raise awareness of vaccine safety and efficacy.

The association of mesothelioma, a lethal lung disease, with asbestos has led to an absolute ban on asbestos in at least 55 countries worldwide. The purpose of this paper is to review residual exposure to asbestos as well as other emerging causes of mesothelioma outside asbestos. The review provides detailed description of asbestos minerals, their geographical locations, mesothelioma in these areas, as well as contemporary possible sources of asbestos exposure. Second, we examine other emerging causes of mesothelioma including: ionizing radiation as the second most important risk factor after asbestos, particularly relevant to patients undergoing radiotherapy, third, carbon nanotubes which are under investigation and fourth, Simian virus 40. In the case of asbestos per se, the greatest risk is from occupational exposure during mining and subsequent processing. Of the non-occupational exposures, environmental exposure is most serious, followed by exposure from indoor asbestos minerals and secondary familial exposure. Overall, asbestos is still a major risk factor, but alternative causes should not be neglected, especially in young people, in women and those with a history of radiotherapy or living in high-risk locations.

Prediabetes is a glucose metabolism disorder considered as a distinct nosological entity which strongly predicts the development of type 2 diabetes mellitus. This nosological entity itself is a serious condition indicating an increased risk of atherosclerotic and oncological complications. In patients with prediabetes, other components of metabolic syndrome are usually present, such as arterial hypertension, obesity or dyslipidaemia, further increasing an individual's risk of morbidity and mortality. Prediabetes is a long-developing disorder which offers enough time for early diagnosis and intervention; it may even be reversible. This review summarizes current knowledge on the definition, detection, epidemiology, cardiovascular and other consequences of prediabetes. It also gives suggestions for future research, along with recommendations for clinical practice.

Aims: Pleural mesothelioma is a highly aggressive and difficult-to-treat form of cancer induced by asbestos in 80-90% of cases. The population group most at risk of the condition are asbestos-exposed workers. Mesothelin or soluble mesothelin-related protein (SMRP) is studied as a potential marker of mesothelioma in the at-risk population. Methods: The study comprised 239 subjects with a mean duration of occupational exposure to asbestos of 19.9 years. In all of them, a complete medical history was taken, focused on exposure duration and a physical examination, a chest X-ray or other imaging investigations and a lung function test were performed. Their serum SMRP levels were measured and biopsy samples were taken to diagnose pleural disease. Based on the above examinations, the subjects were classified into subgroups and serum SMRP concentrations were statistically analyzed with respect to individual parameters. Results: In asbestos-exposed individuals, mesothelin levels were significantly higher in those with pathological X-ray findings than in those with normal X-ray results (0.78 ± 0.63 vs. 0.50 ± 0.35, P

Protection of healthcare workers (HCWs) against influenza is essential for patient health and a functional health system. The study aimed to analyze the demand for seasonal influenza vaccination (SIV) among various groups of HCWs in a tertiary care hospital before and during the COVID-19 pandemic and to identify their motives for this season’s SIV. Before this influenza season (2020/21), the hospital management offered free SIV to all HCWs and promoted it on the internal network. Out of 4,167 HCWs, 630 HCWs expressed interest in SIV and were vaccinated in the hospital. They filled in a total of 603 self-administered pen-and-paper questionnaires. The mean age of the respondents (374 females and 229 males) was 45 ± 12 years. Physicians accounted for 48% of the vaccinated persons but for only 24% (p

The presented case demonstrates that acute lead poisoning may occur due to just short-term exposure to a mixture of lead-containing dust and ammunition. Such exposure may result in high blood lead levels persisting for years in the absence of any symptoms. A middle-aged male with a history of an approximately 7-day cleanup of an old recreational firing range with large ammunition and dust deposits presented to an emergency department with abdominal pain, dyspnea, fatigue and impaired cognitive function. Given his occupational history, specific tests were performed that showed high lead concentrations in both blood and urine. The patient was diagnosed with acute lead poisoning. He was started on chelation therapy that improved both clinical and laboratory parameters. Over a subsequent nearly 3-year follow-up, the patient’s blood lead levels fluctuated and continued to be increased. Given the absence of other sources of lead exposure, these were likely due to the formation of bone deposits. Med Pr. 2020;71(3):375–9

Objectives: Carpal tunnel syndrome (CTS) is a common occupational disease. The aim was to assess the effect of preventive measures in automotive assembly workers. Material and Methods: The analysis summarizes data from annual crosssectional studies. The 7-year analysis of data was based on medical records obtained from an occupational physician and inspections carried out at the workplace where targeted preventive measures were introduced, including better ergonomic arrangement of the workplace, technical adjustments facilitating the work, preventive nerve conduction studies (NCS) testing of the median nerve once a year, switching of workers and their targeted rotation within the workplace. The NCS testing of median nerve conduction at the wrist was the basic objective method for assessment of the prevalence and severity of CTS. Over the study period, the sample comprised 1804 workers at risk for repetitive overuse of the upper extremities, of whom 281 were females with a mean age of 38.5 years and 1523 were males with a mean age of 31.4 years. Results: Over the study period, a total of 13 cases of CTS were recognized as an occupational disease in the plant, 8 of which occurred within the first 2 years from the initiation of production. Introduction of preventive measures decreased the prevalence of median neuropathy from 18.3% of examined extremities in 2011 to 10.5% in 2013 (p = 0.003). In early 2014, the production pace increased and this was accompanied by a rise in abnormal NCS findings to 16.9%. Over the study period, the rate of sensorimotor neuropathy decreased in favor of merely sensory neuropathies, which have been most frequent since 2013. The percentage of employees whose contracts were terminated due to median neuropathy decreased steadily from 5.5% to 0.4%. Conclusions: Targeted prevention of work-related CTS is effective as evidenced by the decrease in the prevalence of median neuropathy detected by NCS. Int J Occup Med Environ Health 2017;30(1):45–54

Objectives: Malignant mesothelioma (MM) is the most serious asbestos-related disease. Its increasing incidence is alarming, suggesting the need for as early diagnosis as possible. This 4.5-year prospective longitudinal study aimed at assessing the benefit of measuring serum mesothelin as a marker for diagnosing malignant mesothelioma in individuals with previous occupational exposure to asbestos, as a part of their clinical follow-up care. Material and Methods: The study comprised 309 participants (235 males, 74 females) with a mean age of 58.9 years (standard deviation (SD) = 9.8) and a mean duration of exposure to asbestos dust of 13.4 years (SD = 9.3). From 2009 to June 2013, all subjects were followed at a department of occupational medicine in Olomouc. Apart from the standard parts of medical examination (history, physical examination, simple chest radiographs and spirometry), the patients’ serum mesothelin levels were determined by the Mesomark immunoenzymatic diagnostic assay. Statistical analysis of the validity of serum mesothelin level measurement was carried out with respect to the diagnosis of MM. Results: Among the participants, 16 (5.2%) individuals (14 males and 2 females) were diagnosed with malignant mesothelioma. Based on the detected mesothelin levels, their validity for prediction of malignant mesothelioma was calculated as follows: sensitivity – 0.75, specificity – 0.962, positive predictive value – 0.706, negative predictive value – 0.969, positive and negative likelihood ratios – 19.95 and 0.26, respectively, and diagnostic odds ratio – 76.8, at a 95% confidence interval. Conclusions: The high specificity was identified indicating the low false positivity as well. In the case of detecting elevated soluble mesothelin-related peptides (SMRP) levels in formerly asbestos-exposed individuals, the possibility of the presence of MM should be included into the clinical consideration. The high negative predictive value denotes a lower probability of the presence of MM in patients with normal SMRP levels but due to the limiting lower sensitivity this possibility cannot be entirely excluded.

Background and objectives: The visceral adiposity index (VAI), estimating visceral adiposity dysfunction through a simple formula, could serve as a useful tool for identifying individuals at higher cardiometabolic risk. Its relationship with insulin resistance (IR), assessed using the homeostasis model assessment of IR (HOMA-IR), and metabolic syndrome (MetS) components remains unclear. The study aimed to investigate the association of VAI with both HOMA-IR and MetS. Materials and Methods: After undergoing anthropometric and biochemical studies, 783 individuals were divided into three groups according to a number of present MetS components. The VAI cut-offs signaling MetS and HOMA-IR were determined by maximizing the sum of the sensitivity and specificity. Correlation analysis was performed to explore the associations between VAI and other tested parameters. A logistic stepwise regression analysis was applied to identify statistically significant determinants of HOMA-IR. Given the variability of reference values, two thresholds of HOMA-IR were applied, namely 2.0 and 3.8. Results: VAI increased significantly between the groups with a rising number of MetS components. The VAI cut-off for MetS was 2.37, with a sensitivity of 0.86 and a specificity of 0.78. The same cut-off point identified subjects with HOMA-IR = 3.8, with a sensitivity of 0.79 and a specificity of 0.66. The VAI cut-off for HOMA-IR = 2.0 was 1.89, with a sensitivity of 0.74 and a specificity of 0.68. The strongest correlations of VAI were noted with HOMA-IR (r = 0.51) and insulin (r = 0.49), respectively, while the strongest correlation of HOMA-IR was with waist circumference (r = 0.54). Not one of the routine parameters was a significant predictor in the regression analysis. Conclusions: The obtained results show an existing association of VAI with HOMA-IR. The high sensitivity and specificity of the cut-offs may allow the application of VAI in common clinical practice.

Objectives: Health care workers constitute a high-risk occupational category owing to the character of their work that includes high-risk environment, shift work and mental as well as physical stress. In occupational medicine, caring for their health condition should be a priority and include measures aimed at preventing cardiovascular diseases. The study aimed at determining the prevalence of cardiovascular disease (CVD) risk factors in employees of a large hospital and assessing their effect on the incidence of cardiovascular events. Materials and Methods: The group comprised 3124 employees with a mean age of 36.1 years (SD = 11.4), out of whom 562 were males (mean age of 37.1 years, range: 18-72; SD = 12.26) and 2562 were females (mean age of 35.9 years, range: 18-68; SD = 11.24). At their initial examination, the employees filled in a questionnaire on basic CVD risk factors (according to valid recommendations). This was supplemented with objective data to determine the risk of CVD using valid charts. From this group, a subset of persons at a high or intermediate risk was selected, comprising 247 individuals with a mean age of 54.1 years (SD = 5.73). After 5-9 years (mean 7.24±1.38 years), they either underwent another examination or their health status was ascertained by phone or in a computer database. The end point was the incidence of cardiovascular events (sudden death, acute myocardial infarction, unstable angina pectoris, percutaneous coronary intervention, cardiac failure, stroke or transient ischemic attack). Results: The end point was noted in a total of 15 males (6.07%) and 6 females (2.42%), being statistically significantly present in managers (males p < 0.00007, females p < 0.00001), male physicians/surgeons (p < 0.025), tertiary-educated males (p < 0.0095), female smokers (p < 0.015), male ex-smokers (p < 0.007), overweight or obese males (p < 0.02) and those with the waist-to-hip ratio above 1.0 (p < 0.005). Conclusions: Cardiovascular events are most likely to occur in obese male physicians/surgeons holding managerial positions and in female managers.