Exploring the Applicability of Physiological Monitoring to Manage Physical Fatigue in Firefighters.

Physical fatigue reduces productivity and quality of work while increasing the risk of injuries and accidents among safety-sensitive professionals. To prevent its adverse effects, researchers are developing automated assessment methods that, despite being highly accurate, require a comprehensive understanding of underlying mechanisms and variables' contributions to determine their real-life applicability. This work aims to evaluate the performance variations of a previously developed four-level physical fatigue model when alternating its inputs to have a comprehensive view of the impact of each physiological variable on the model's functioning. Data from heart rate, breathing rate, core temperature and personal characteristics from 24 firefighters during an incremental running protocol were used to develop the physical fatigue model based on an XGBoosted tree classifier. The model was trained 11 times with different input combinations resulting from alternating four groups of features. Performance measures from each case showed that heart rate is the most relevant signal for estimating physical fatigue. Breathing rate and core temperature enhanced the model when combined with heart rate but showed poor performance individually. Overall, this study highlights the advantage of using more than one physiological measure for improving physical fatigue modelling. The findings can contribute to variables and sensor selection in occupational applications and as the foundation for further field research.

Machine Learning Approach to Model Physical Fatigue during Incremental Exercise among Firefighters.

Physical fatigue is a serious threat to the health and safety of firefighters. Its effects include decreased cognitive abilities and a heightened risk of accidents. Subjective scales and, recently, on-body sensors have been used to monitor physical fatigue among firefighters and safety-sensitive professionals. Considering the capabilities (e.g., noninvasiveness and continuous monitoring) and limitations (e.g., assessed fatiguing tasks and models validation procedures) of current approaches, this study aimed to develop a physical fatigue prediction model combining cardiorespiratory and thermoregulatory measures and machine learning algorithms within a firefighters' sample. Sensory data from heart rate, breathing rate and core temperature were recorded from 24 participants during an incremental running protocol. Various supervised machine learning algorithms were examined using 21 features extracted from the physiological variables and participants' characteristics to estimate four physical fatigue conditions: low, moderate, heavy and severe. Results showed that the XGBoosted Trees algorithm achieved the best outcomes with an average accuracy of 82% and accuracies of 93% and 86% for recognising the low and severe levels. Furthermore, this study evaluated different methods to assess the models' performance, concluding that the group cross-validation method presents the most practical results. Overall, this study highlights the advantages of using multiple physiological measures for enhancing physical fatigue modelling. It proposes a promising health and safety management tool and lays the foundation for future studies in field conditions.

Influence of severe cold thermal environment on core and skin temperatures: A systematic review.

BACKGROUND: Exposure to severe cold thermal environment (SCE) is a significant risk factor in the frozen food industry, influencing health and safety of the employees. OBJECTIVE: The aim of this work is to present the level of knowledge on the influence of SCE on core and skin temperatures. METHODS: The review has been conducted using appropriated keywords and expressions, by searching 21 electronic databases and references of the included articles. Only research articles with healthy subjects and considering exposure to SCE conditions (- 5°C or lower) were considered. RESULTS: Thirteen articles were included in the systematic review which met the research objective and were in accordance with the inclusion and exclusion criteria. All the included studies measured core or skin temperatures. CONCLUSIONS: The main findings of this review indicate that working in SCE is and will remain an added risk factor. Further studies should be conducted in laboratory and industrial severe cold thermal environments on acclimatized and non-acclimatized subjects, in order to evaluate core and skin temperature variations and its recovery periods.

Sjögren's syndrome and acquired splenic atrophy with septic shock: a case report.

INTRODUCTION: The most frequent causes of adult-onset recurrent infections are human immunodeficiency virus infection, malignancy, and autoimmune diseases, while acquired non-surgical hyposplenism is rare. Although acquired asplenia/hyposplenism have been described in association with celiac disease and, less frequently, with autoimmune diseases such as Sjögren's syndrome, the manifestations in this context are usually only detectable in the laboratory setting, with Howell-Jolly bodies or thrombocytosis. To the best of our knowledge, no previous case of pneumococcal septic shock in a patient with acquired hyposplenism and co-morbid Sjögren's syndrome has been reported. CASE PRESENTATION: We report a case of a 45-year-old Caucasian woman who developed pneumococcal pneumonia at age 42 years, pneumococcal meningitis at age 44 years and septic shock with Streptococcus agalactiae bacteremia at age 45 years and was subsequently diagnosed with radiological splenic atrophy and functional asplenia, as well as primary Sjögren's syndrome. After appropriate immunizations, the patient has been free from clinically important infections. CONCLUSION: Hyposplenism should be suspected in patients with adult-onset infections caused by encapsulated bacteria, especially if autoantibodies are present. Early diagnosis can help prevent potentially life-threatening infections. Possible associations between splenic atrophy and Sjögren's syndrome are discussed.

Frequent detection of latent tuberculosis infection among aged underground hard coal miners in the absence of recent tuberculosis exposure.

BACKGROUND: Miners are at particular risk for tuberculosis (TB) infection due to exposure to silica dust and silicosis. The objectives of the present observational cohort study were to determine the prevalence of latent TB infection (LTBI) among aged German underground hard coal miners with silicosis or chronic obstructive pulmonary disease (COPD) using two commercial interferon-gamma release assays (IGRAs) and to compare their performance with respect to predictors of test positivity. METHODS: Between October 2008 and June 2010, miners were consecutively recruited when routinely attending pneumoconiosis clinics for an expert opinion. Both IGRAs, the QuantiFERON®-TB Gold In-Tube (QFT) and the T-SPOT®.TB (T-SPOT), were performed at baseline. A standardized clinical interview was conducted at baseline and at follow-up. The cohort was prospectively followed regarding the development of active TB for at least two years after inclusion of the last study subject. Independent predictors of IGRA positivity were calculated using logistic regression. RESULTS: Among 118 subjects (mean age 75 years), none reported recent exposure to TB. Overall, the QFT and the T-SPOT yielded similarly high rates of positive results (QFT: 46.6%; 95% confidence interval 37.6-55.6%; T-SPOT: 61.0%; 95% confidence interval 52.2-69.8%). Positive results were independently predicted by age ≥80 years and foreign country of birth for both IGRAs. In addition, radiological evidence of prior healed TB increased the chance of a positive QFT result fivefold. While 28 subjects were lost to follow-up, no cases of active TB occurred among 90 subjects during an average follow-up of >2 years. CONCLUSIONS: Considering the high prevalence of LTBI, the absence of recent TB exposure, and the currently low TB incidence in Germany, our study provides evidence for the persistence of specific interferon-gamma responses even decades after putative exposure. However, the clinical value of current IGRAs among our study population, although probably limited, remains uncertain.

Screening for tuberculosis and prediction of disease in Portuguese healthcare workers.

INTRODUCTION: Results of systematic screening of healthcare workers (HCWs) for tuberculosis (TB) with the tuberculin skin test (TST) and interferon-γ release assays (IGRA) in a Portuguese hospital from 2007 to 2010 are reported. METHODS: All HCWs are offered screening for TB. Screening is repeated depending on risk assessment. TST and QuantiFERON Gold In-Tube (QFT) are used simultaneously. X-ray is performed when TST is > 10 mm, IGRA is positive or typical symptoms exist. RESULTS: The cohort comprises 2,889 HCWs. TST and IGRA were positive in 29.5%, TST-positive but IGRA-negative results were apparent in 43.4%. Active TB was diagnosed in twelve HCWs - eight cases were detected during screening and four cases were predicted by IGRA as well as by TST. However, the progression rate in IGRA-positive was higher than in TST-positive HCWs (0.4% vs. 0.2%, p-value 0.06). CONCLUSIONS: The TB burden in this cohort was high (129.8 per 100,000 HCWs). However, the progression to active TB after a positive TST or positive IGRA was considerably lower than that reported in literature for close contacts in low-incidence countries. This may indicate that old LTBI prevails in these HCWs.

Within-subject variability of Mycobacterium tuberculosis-specific gamma interferon responses in German health care workers.

Gamma interferon (IFN-γ) release assays (IGRAs) are used increasingly for the periodic tuberculosis (TB) screening of health care workers (HCWs), although data regarding the reproducibility and interpretation of serial testing results in countries with a low incidence of TB are scarce. The present study evaluated and compared the within-subject variability of dichotomous and continuous results of two commercial IGRAs, the QuantiFERON-TB Gold In-Tube (QFT) and the T-SPOT.TB (T-SPOT), in German HCWs during a 4-week period. Thirty-five immunocompetent HCWs with low or medium TB screening risk and without known recent TB exposure or tuberculin skin test application were tested repeatedly with both IGRAs at weekly intervals. A total of 158 valid results were obtained for each IGRA. Changes of about ±70% (QFT) and ±60% (T-SPOT) from the mean IFN-γ response accounted for 95% of the within-subject variability. However, according to the manufacturers' cutoffs, inconsistent results were observed more frequently for the QFT (28.6%; four conversions, six reversions) than for the T-SPOT (8.6%; three reversions; P < 0.001). The overall agreement between the IGRAs was good. Regression toward the means accounted for a significant decline in mean IFN-γ responses of about 25% between successive visits for both IGRAs. Although both assays were highly reliable and reproducible, we observed substantial within-subject variability and regression toward the means during a 4-week period, which should be considered when interpreting serial testing results in comparable populations and settings. Our data support the use of borderline zones for the interpretation of serial IGRA results and the retesting of borderline positive results before offering preventive chemotherapy.

Serial testing with the interferon-γ release assay in Portuguese healthcare workers.

OBJECTIVES: Evidence for the utility of the new Mycobacterium tuberculosis (MTB) specific IFN-γ release assays in diagnosing latent tuberculosis infection (LTBI) is growing. However, data concerning conversion and reversion rates in serial testing of healthcare workers (HCWs) with an interferon-γ release assay are sparse. METHODS: Between February 2007 and September 2009, 670 HCWs in the University Hospital of Porto, Portugal were tested at least twice with QuantiFERON-TB® Gold In-Tube (QFT) for LTBI. The tuberculin skin test (TST) was performed simultaneously. QFT was considered positive if INF-γ ≥0.35 IU/mL. TST conversion was defined as an increase ≥10 or ≥6 mm compared to a baseline TST <10 mm. RESULTS: The second QFT was positive in 4.8% of the 376 HCWs with an INF-γ concentration at baseline below 0.1 IU/mL but in 48.8% of the 41 HCWs with an INF-γ concentration of 0.2 to <0.35 IU/mL. Out of 74 HCWs with a baseline INF-γ concentration ≥3.0 IU/mL, 4 (5.4%) reversed while 27 out of 55 HCWs (49%) with a baseline INF-γ concentration ≥0.35 to <0.7 IU/mL reversed to a negative QFT. Those 61 HCWs with TST conversion (increase ≥10 mm) were most often (78.7%) negative in both consecutive QFTs. CONCLUSION: Our data suggests the use of an uncertainty zone between 0.2 and 0.7 IU/mL in serial testing with QFT. As long as the knowledge regarding disease progression in QFT-positive persons is limited, persons pertaining to this zone should be retested before being offered preventive chemotherapy.

Serial testing with an interferon-γ release assay in German healthcare workers.

AIM: Data concerning conversion and reversion rates in the serial testing of healthcare workers (HCWs) is rare. So far, there is no consensus on how to define and interpret interferon-gamma release assays (IGRA) conversions and reversions, or how to deal with such results. We analysed conversion and reversion rates in the serial testing of HCWs using an IGRA. METHODS: The study population comprises 287 HCWs, who participated in routine occupational safety and health screening for latent tuberculosis infection (LTBI) with the QuantiFERON-TB(®) Gold In-Tube assay (QFT). Four different definitions for conversion and reversion were applied: 1) transgression or regression above/below the cut-off; 2) increase from <0.2 to >0.7 IU/ml or decrease from >0.7 to <0.2 IU/ml; 3) transgression or regression above/below the cut-off plus change of ≥0.50 IU/ml; and 4) transgression or regression above/below the cut-off plus change of ≥0.70 IU/ml. RESULTS: The highest conversion and reversion rates of 6.1% (95% CI 3.5 to 9.9) and 32.6% (95% CI 19.1 to 48.5) respectively were observed with the least stringent definition of negative to positive. The most stringent definition of an increase of ≥0.7 IU/ml above the cut-point produced the lowest conversion rate of 2.5% (95% CI 0.9 to 5.3). Using an uncertainty zone from 0.2 to 0.7 IU/ml gave low conversion (2.6%) and reversion rates (15.4%). CONCLUSION: Our data confirmed the findings of previous studies that suggest that a simplistic dichotomous negative to positive definition of the IGRA might be deceptive because of the high number of spontaneous conversions and reversions. Therefore using an uncertainty zone around the cut-point (e.g. 0.2 to 0.7 IU/ml) could improve the discrimination between unspecific variation around the diagnostic cut-off and true conversion or reversion.

Fertility disorders and pregnancy complications in hairdressers - a systematic review.

BACKGROUND: Hairdressers often come into contact with various chemical substances which can be found in hair care products for washing, dyeing, bleaching, styling, spraying and perming. This exposure can impair health and may be present as skin and respiratory diseases. Effects on reproduction have long been discussed in the literature. METHOD: A systematic review has been prepared in which publications from 1990 to 2010 were considered in order to specifically investigate the effects on fertility and pregnancy. The results of the studies were summarised separately in accordance with the type of study and the examined events. RESULTS: A total of 2 reviews and 26 original studies on fertility disorders and pregnancy complications in hairdressers were found in the relevant databases, as well as through hand searches of reference lists. Nineteen different outcomes concerning fertility and pregnancy are analysed in the 26 original studies. Most studies looked into malformation (n = 7), particularly orofacial cleft. Two of them found statistically significant increased risks compared to five that did not. Small for gestational age (SGA), low birth weight (LBW) and spontaneous abortions were frequently investigated but found different results. Taken together the studies are inconsistent, so that no clear statements on an association between the exposure as a hairdresser and the effect on reproduction are possible. The different authors describe increased risks of infertility, congenital malformations, SGA, LBW, cancer in childhood, as well as effects from single substances. CONCLUSION: On the basis of the identified epidemiological studies, fertility disorders and pregnancy complications in hairdressers cannot be excluded. Although the evidence for these risks is low, further studies on reproductive risks in hairdressers should be performed as there is a high public health interest.

Results of five-year systematic screening for latent tuberculosis infection in healthcare workers in Portugal.

INTRODUCTION: The risk of tuberculosis (TB) in healthcare workers (HCWs) is related to its incidence in the general population, and increased by the specific risk as a professional group. The prevalence of latent tuberculosis infection (LTBI) in HCWs in Portugal using the tuberculin skin test (TST) and the interferon-gamma release assays (IGRA) was analyzed over a five-year period. METHODS: A screening programme for LTBI in HCWs was conducted, with clinical evaluations, TST, IGRA, and chest radiography. Putative risk factors for LTBI were assessed by a standardised questionnaire. RESULTS: Between September 2005 and June 2009, 5,414 HCWs were screened. The prevalence of LTBI was 55.2% and 25.9% using a TST >/= 10 mm or an IGRA test result (QuantiFERON-TB Gold In-Tube) INF-gamma >/=0.35 IU/mL as a criterion for LTBI, respectively. In 53 HCWs active TB was diagnosed. The number of HCWs with newly detected active TB decreased from 19 in the first year to 6 in 2008. Risk assessment was poorly related to TST diameter. However, physicians (1.7%) and nurses (1.0%) had the highest rates of active TB. CONCLUSIONS: LTBI and TB burden among HCWs in Portugal is high. The screening of these professionals to identify HCWs with LTBI is essential in order to offer preventive chemotherapy to those with a high risk of future progression to disease. Systematic screening had a positive impact on the rate of active TB in HCWs either by early case detection or by increasing the awareness of HCWs and therefore the precautions taken by them.

[Tuberculosis in hospital department health care workers]. / Tuberculose em profissionais de saúde de um serviço hospitalar.

INTRODUCTION: Tuberculosis (TB) is considered an occupational disease in health care workers (HCW) and its transmission in health care facilities is an important concern. Some hospital departments are at higher risk of infection. OBJECTIVE: To describe TB cases detected after TB screening in HCW from a hospital department (Ear, Nose and Throat - ENT) who had had contact with active TB cases. MATERIAL AND METHODS: All HCW (73) from Hospital São João's ENT Unit who had been in contact with two in-patients with active TB underwent TB screening. Those who had symptoms underwent chest X-ray and mycobacteriological sputum exam. RESULTS: Of 73 HCW who underwent TB screening, TB diagnosis was established in 9 (8 female; median age: 30 years; 1 doctor, 6 nurses, 2 nursing auxiliaries). Pulmonary TB was found in 8 and extra- -pulmonary TB in 1. Microbiology diagnosis was obtained in 7 cases by sputum smear, n=2; culture exam in bronchial lavage, n=4 and histological exam of pleural tissue, n=1. In 4 cases, Mycobacterium tuberculosis genomic DNA was extracted from cultures and molecular typing was done. All cases had identical MIRU types, which allowed identification of the epidemiological link. CONCLUSION: Nosocomial TB is prominent and efforts should be made to implement successful infection control measures in health care facilities and an effective TB screening program in HCW. Molecular typing of Mycobacterium tuberculosis facilitates cluster identification.