Average uranium bedrock concentration in Swedish municipalities predicts male lung cancer incidence rate when adjusted for smoking prevalence: Indication of a cumulative radon induced detriment.

Bedrock U has been used as a proxy for local indoor radon exposure. A preliminary assessment of cancer incidence rate in a cohort of 809,939 adult males living in 9 different Swedish counties in 1986 has been used to correlate the cumulative lung cancer and total cancer (excluding lung) incidence rates between 1986 and 2020, respectively with the municipality average value of bedrock U concentration obtained from Swedish geological Survey (SGU). To control for regional difference in tobacco smoking, data on county average smoking prevalence, obtained from a survey conducted by the Public Health Agency of Sweden from 2001 to 2004, was used. Regression analysis shows that there is a significant positive correlation between smoking prevalence adjusted lung cancer incidence rate in males and the municipality bedrock U concentration (R2 = 0.273 with a slope 5.0 ±â€¯0.87·10-3 ppm-1). The correlation is even more significant (R2 = 0.759 with a slope = 4.8 ±â€¯0.25·10-3 ppm-1) when assessed on population weighted cancer incidence data binned in nine intervals of municipality average bedrock U concentration (ranging from 0.97 to 4.9 ppm). When assessing the corresponding correlations for total cancer incidence rate (excluding cancer of the lung) with adjustment for smoking prevalence, there appears to be no or little correlation with bedrock U concentration (R2 = 0.031). We conclude that an expanded future study needs age-standardized cancer incidence data to obtain a more consistent exposure-response model. Such model could be used to predict future lung cancer cases based on geological survey maps of bedrock U as an alternative to laborious indoor radon measurements, and to discern what future lung cancer rates can be expected for a population nearing zero smoking prevalence, with and without radon prevention.

Dose-response analysis of protracted absorbed organ dose and site-specific cancer incidence in Sweden after the Chernobyl nuclear power plant accident.

Background: Adult males in Sweden exhibit an increased risk of cancer associated with an increased absorbed dose to the colon from the Chernobyl accident. Methods: A closed cohort, with information on hunter status, included all individuals living in northern Sweden in 1986. Complete annual information on exposure to 137Cs at the dwelling coordinate was available for a total of 2,104,101 individuals. A nested case-control method with four controls matched for year of cancer diagnosis and year of birth, was used. Individual absorbed organ doses were calculated between 1986 and 2020 including external and internal exposure. Hazard ratios (HR) per mGy with 95% confidence intervals (95% CI) were calculated using conditional logistic regression adjusted for rural/nonrural habitat, education level and pre-Chernobyl cancer incidence 1980 to 1985. A total of 161,325 cancer cases in males and 144,439 in females were included. Results: The adjusted HR per mGy for all cancer sites combined was 1.027 (95% CI = 1.022, 1.031) in males and 1.011 (95% CI = 1.006, 1.017) in females. In a post hoc analysis accounting for both remaining confounding from hunter lifestyle and the pre-Chernobyl cancer incidence by county, the adjusted HR per mGy for all cancer sites combined was 1.014 (95% CI = 1.009, 1.019) in males and 1.000 (95% CI = 0.994, 1.006) in females. The post hoc analysis suggested an increased risk of cancer in the colon, pancreas, and stomach, respectively, in males, and lymphoma in females. Conclusions: Increased cancer risk estimates were found for some specific cancer sites but remaining uncontrolled confounding due to hunter lifestyle could not be ruled out.

Cancer incidence in a male adult population in relation to estimated protracted colon dose - A nested case control study in Northern Sweden after the Chernobyl Nuclear Power Plant accident.

INTRODUCTION: Uncertainty in the dose-response of low dose radiation raised concern of an increased cancer incidence in Sweden after the Chernobyl Nuclear Power Plant (NPP) accident. MATERIAL AND METHODS: A closed cohort was created of all males ≥18 years of age living in the Northern Sweden in 1986. In total 826,400 individuals were enrolled including 40,874 hunters. A nested case-control design was used with five controls randomly selected for each cancer case matched on year of diagnosis and year of birth. Individual absorbed colon dose was calculated 1986 to 2015. Allowing for a 5-year latency period Hazard Ratios (HR) per mGy with 95% Confidence Intervals (95% CI) were calculated in a conditional logistic regression adjusted by rural/non-rural living, length of education and pre-Chernobyl cancer incidence 1980 to 1985. A total of 127,109 cancer cases occurred from 1 January 1991 to 31 December 2015. Cancer was classified in: 1) Organ-specific (stomach, colon, liver, lung, prostate, urinary bladder, thyroid and leukaemia), 2) Other and 3) Not previously associated to ionizing radiation. RESULTS: The average colon dose in cases was 1.77 mGy compared to controls 1.73 mGy. Hunters average colon dose was 2.32 mGy. Organ-specific cancers showed the highest HR per mGy both in the full cohort, adj HR 1.019 (1.014-1.024) and the hunter subcohort, adj HR 1.014 (1.001-1.027) during follow-up 1991 to 2015. Other cancer and Not previously associated with ionizing radiation showed lower HR per mGy. Therefore, the adj HR per mGy for Total cancer, 1.013 (1.009-1.017) was explained by Organ-specific cancer. Increased adj HR per mGy was seen in stomach, colon and prostate cancer, respectively in the full cohort and lung cancer in hunters. CONCLUSIONS: Some cancer sites previously associated with ionizing radiation showed a positive adjusted HR per mGy both in the full cohort and in the hunter subcohort.

Absorbed dose rate coefficients for134Cs and137Cs with steady-state distribution in the human body:S-coefficients revisited.

In the event of an accidental release of radioactive elements from a nuclear power plant, it has been shown that the radionuclides contributing the most to long-term exposure are134Cs and137Cs. In the case of nuclear power plant fallout, with subsequent intake of radionuclides through the food chain, the internal absorbed dose to target tissues from protracted intake of radionuclides needs to be estimated. Internal contamination from food consumption is not caused by a single intake event; hence, the committed equivalent dose, calculated by a dose coefficient or dose per content function, cannot be easily used to calculate the cumulative absorbed dose to relevant target tissues in the body. In this study, we calculated updated absorbed dose rate coefficients for134Cs and137Cs based on data from the International Commission on Radiological Protection (ICRP) on specific absorbed fractions. The absorbed dose rate coefficients are provided for male and female adult reference phantoms, respectively, assuming a steady-state distribution of Cs that we calculated from the ICRP biokinetic model for Cs. With these coefficients, the absorbed dose to the listed target tissues, separately and to the total body, are related to the number of nuclear transitions (time-integrated activity) in each listed source region. Our new absorbed dose rate coefficients are given for the complete set of target tissues and have not been presented before. They are also provided for aggregated categories of organs to facilitate epidemiological studies.

Shorter time to clinical decision in work-related asthma using a digital tool.

PEF curves are a useful but cumbersome tool in diagnosing work-related asthma. Using a digital spirometer and smartphone app, time to clinical decision could be shortened by 6-7 weeks. Physician's time spent analysing PEF data is also shortened. https://bit.ly/3d5SY78.

Nurse managers in perioperative settings and their reasons for remaining in their jobs: A qualitative study.

AIM: The study describes what helps nurse managers maintain the strength to keep going as leaders. BACKGROUND: Good leadership is important for the quality of patient care, patient satisfaction in care and efficiency. Many nurse managers stay on despite challenges at work. METHODS: Twelve nurse managers were interviewed. Data were analysed by systematic text condensation according to Malterud. RESULTS: The results were as follows: A-Walking side by side with my employees; B-Knowing that I mean something to my employees; C-Talking to myself-asking myself tough questions; D-Having someone to talk to, to decrease the feeling of being alone; E-Leading and managing in my own way-the fear of not succeeding is my motivation. CONCLUSION: The nurse managers built their own strategies to get through and get on when difficult situations arose. In order to succeed in leading their employees, the nurse managers gathered their inner strength through moving caritatively back and forth between the 'secret room' and the 'staff room' in the house of leadership. IMPLICATIONS IN NURSING MANAGEMENT: The manuscript gives insights into where nurse managers found sources of strengths in their everyday work. To realize their employees' strengths and motivation made a difference for nurse managers as a driving force. By having someone to talk to and by asking themselves tough questions, they were prepared for the challenges that came.

Introduction of a method to calculate cumulative age- and gender-specific lifetime attributable risk (LAR) of cancer in populations after a large-scale nuclear power plant accident.

The effect of age and gender in risk estimates related to long-term residence in areas contaminated by nuclear power plant fallout was evaluated by applying the lifetime attributable risk (LAR) concept to an existing exposure model that was previously used for cumulative effective dose estimates. In this study, we investigated the influence of age distribution on the number of cancer cases by applying five different age distributions from nuclear power-producing countries (India, Japan, South Korea, and the United States), and Egypt because of intentions to develop nuclear power. The model was also used to estimate the effective dose and gender-specific LAR as a function of time after fallout for the offspring of the population living in 137Cs fallout areas. The principal findings of this study are that the LAR of cancer incidence (excluding non-fatal skin cancers) over 70 y is about 4.5 times higher for newborn females (5.4% per MBq m-2 of initial 137Cs ground deposition) than the corresponding values for 30 y old women (1.2% per MBq m-2 137Cs deposition). The cumulative LAR for newborn males is more than 3 times higher (3.2% versus 1.0% per MBq m-2 137Cs deposition). The model predicts a generally higher LAR for women until 50 y of age, after which the gender difference converges. Furthermore, the detriment for newborns in the fallout areas initially decreases rapidly (about threefold during the first decade) and then decreases gradually with an approximate half-time of 10-12 y after the first decade. The age distribution of the exposed cohort has a decisive impact on the average risk estimates, and in our model, these are up to about 65% higher in countries with high birth rates compared to low birth rates. This trend implies larger average lifetime attributable risks in countries with a highly proportional younger population. In conclusion, the large dispersion (up to a factor of 4 between newborns and 30 y olds) in the lifetime detriment per unit ground deposition of 137Cs over gender and age in connection with accidental nuclear releases justifies the effort in developing risk models that account for the higher radiation sensitivity in younger populations.

Increased cancer risk in male hunters compared to the general male population in Northern Sweden after the Chernobyl Nuclear Power Plant accident?

Male hunters in Swedish counties with high fallout of 137Cs after the Chernobyl Nuclear Power Plant (NPP) accident have higher radiation exposure due to higher consumption of game compared with the general population. METHODS: Cancer incidence in Sweden was studied in 9 counties with different 137Cs fallout after the Chernobyl NPP accident in 1986. In total, 9,267 cancer cases occurred in hunters and 138,909 cancer cases in non-hunters to 31 December 2015. Incidence rate ratios (IRR) with 95% confidence intervals (CI) were calculated using unexposed hunters, or non-hunters, as reference to study internal radiation exposure or hunter life style, respectively. RESULTS: Directly age standardized total cancer incidence showed an increasing trend in non-hunters. For hunters, the total cancer incidence was significantly lower up to 2001 when the total cancer incidence crossed over the weaker non-hunter trend and remained higher for the following 15 years. IRRs for total cancer in hunters versus non-hunters for each county did not show any clear exposure response pattern. IRRs for hunters versus non-hunters were higher regardless of rural/non-rural status with slightly higher risk estimates for the rural settings. The IRR for hunters was 1.06 (95% CI 1.04-1.08) 1986-2015, representing an excess of 531 cancer cases in hunters. CONCLUSION: An increased total incidence of cancer was identified for male hunters compared with male non-hunters. No obvious association between cancer and 137Cs from the Chernobyl NPP accident could be identified, although the exposure classification was too crude to exclude such an association.

Modelling the effective dose to a population from fallout after a nuclear power plant accident-A scenario-based study with mitigating actions.

The radiological consequences of a nuclear power plant (NPP) accident, resulting in the release of radionuclides to the environment, will depend largely on the mitigating actions instigated shortly after the accident. It is therefore important to make predictions of the radiation dose to the affected population, from external as well as internal exposure, soon after an accident, despite the fact that data are scarce. The aim of this study was to develop a model for the prediction of the cumulative effective dose up to 84 years of age based on the ground deposition of 137Cs that is determined soon after fallout. The model accounts for different assumptions regarding external and internal dose contributions, and the model parameters in this study were chosen to reflect various mitigating actions. Furthermore, the relative importance of these parameters was determined by sensitivity analysis. To the best of our knowledge, this model is unique as it allows quantification of both the external and the internal effective dose using only a fallout map of 137Cs after a nuclear power plant accident. The cumulative effective dose over a period of 50 years following the accident per unit 137Cs deposited was found to range from 0.14 mSv/kBq m-2 to 1.5 mSv/kBq m-2, depending on the mitigating actions undertaken. According to the sensitivity analysis, the most important parameters governing the cumulative effective dose to various adult populations during 50 years after the fallout appear to be: the correlation factor between the local areal deposition of 137Cs and the maximum initial ambient dose rate; the maximum transfer from regional average fallout on the ground to body burden; the local areal deposition of 137Cs; and the regional average 137Cs deposition. Therefore, it is important that mapping of local 137Cs deposition is carried out immediately after fallout from a nuclear power plant accident, followed by calculations of radiation doses for different scenarios using well-known parameters, in order to identify the most efficient mitigation strategies. Given this 137Cs mapping, we believe our model is a valuable tool for long-term radiological assessment in the early phase after NPP accidents.

I Stay-Swedish Specialist Nurses in the Perioperative Context and Their Reasons to Stay at Their Workplace.

PURPOSE: To investigate why nurse anesthetists and operating room nurses choose to stay in the same workplace. DESIGN: Qualitative design. METHODS: Individual interviews were conducted with 15 nurse specialists from four hospitals in Sweden. Two men and 13 women aged between 43 and 63 participated. Data were analyzed with systematic text condensation according to Malterud. FINDINGS: Three themes were identified. (1) Organizational stability contributed to low staff turnover, with good spirits between colleagues, representing everyone's equal value and resulting in a feeling of homelikeness. (2) Sustained development in one's own profession. (3) A humane head nurse who was at hand, who was a facilitator, who knew staff members, and eliminated obstacles for them. CONCLUSIONS: In a nonhierarchical and stable organization with a head nurse with caritative leadership skills, a welcoming working environment with opportunities for professional development is created. Thus, nurse specialists choose to stay, contributing to organizational development.

A supportive climate and low strain promote well-being and sustainable working life in the operation theatre.

BACKGROUND: Shortage of health-care workers e.g. in operating theatres is a global problem. A shortage of staff negatively affects patient outcomes, making it important to keep the employees from quitting. The aim of this survey was to study if well-being, zest for work, and thoughts about leaving work in an operating theatre can be related to the psychosocial work environment, as described by the job demand-control-support (JDCS) model. METHODS: A questionnaire was provided to personnel in operating theatres of seven Swedish hospitals (n = 1405, with a response rate of 68%) that included the JDCS model, personal factors, work ability, well-being, zest for work, and thoughts about leaving their position. Ordinal scale regression was used for analyses. RESULTS: A majority reported moderate to high zest for work (76%). A minority (30%) had sometimes thought during at least one month in the last year of leaving their position. Lower social support scores and high demands together with low control (high-strain) scores were related to lower well-being, lower zest for work, and more thoughts about leaving the position. Anaesthetists scored in the low-strain field, nurse anaesthetists and assistant nurses in the passive field, and operating nurses in the active field, in comparison to all personnel. CONCLUSION: According to the JDCS model, both lower social support and high strain were related to lower well-being and negative thoughts about the position. Social support scores were about the same for different occupational groups in the operating theatre, and no occupation scored on average in the high-strain field.

I am quitting my job. Specialist nurses in perioperative context and their experiences of the process and reasons to quit their job.

The lack of specialist nurses in operating theatres is a serious problem. The aim of this study was to describe reasons why specialist nurses in perioperative care chose to leave their workplaces and to describe the process from the thought to the decision. Twenty specialist nurses (i.e. anaesthesia, NA, and operating room nurses) from seven university- and county hospitals in Sweden participated in qualitative individual in-depth interviews. Data were analysed by systematic text condensation. We identified four themes of reasons why specialist nurses quitted their jobs: the head nurses' betrayal and dismissive attitude, and not feeling needed; inhumane working conditions leading to the negative health effects; not being free to decide about one's life and family life being more important than work; and, colleagues' diminishing behaviour. Leaving one's job was described as a process and specialist nurses had thought about it for some time. Two main reasons were described; the head nurse manager's dismissive attitude and treatment of their employees and colleagues' mistreatment and colleagues' diminishing behaviour. Increasing knowledge on the role of the head nurse managers in specialist nurses' decision making for leaving their workplace, and creating a friendly, non-violent workplace, may give the opportunity for them to take action before it is too late.

Modelling the external radiation exposure from the Chernobyl fallout using data from the Swedish municipality measurement system.

In connection with the Chernobyl fallout and the subsequent deposition of radionuclides in Sweden, Swedish municipalities launched a measurement program to monitor the external radiation exposure. This program encompasses measurements of the ambient dose equivalent rate 1 m above ground at selected locations, and repeats those measurements at the same locations at 7-month intervals. Measurement data compiled from the seven locations with the highest deposition were combined with data from aerial surveys since May 1986 of ground deposition of 137Cs, high-resolution gamma spectrometry performed at four locations in May 1986, and measurements from fixed continuous air gamma rate monitoring stations from 28 April to 15 May 1986. Based on these datasets, a model of the time pattern of the external dose rate in terms of ambient dose equivalent rate from the Chernobyl fallout was developed. The decrease in the ambient dose equivalent rate could, on average, be described by a four-component exponential decay function with effective half-times of 6.8 ± 0.3 d, 104 ± 26 d, 1.0 ± 0.02 y and 5.5 ± 0.09 y, respectively. The predominant contributions to the external dose rate in the first month were from short-lived fission products superseded by 134Cs and then 137Cs. Integrated over 70 y and using extrapolation of the curve fits, our model predicts that 137Cs contributes about 60% and 134Cs contributes about 30% of the external effective dose at these seven locations. The projected time-integrated 70 y external effective dose to an unshielded person from all nuclides per unit total activity deposition of 137Cs is estimated to be 0.29 ± 0.0.08 mSv/(kBq m-2). These results are in agreement with those found in Chernobyl contaminated Russian forest areas, and emphasize the usefulness of maintaining a long-term and regular measurement program in contaminated areas.

Estimated lifetime effective dose to hunters and their families in the three most contaminated counties in Sweden after the Chernobyl nuclear power plant accident in 1986 - A pilot study.

Hunters and their families were one of the most exposed subpopulations in Sweden after the Chernobyl nuclear power plant accident in 1986. In this pilot study we used existing registries and whole-body measurements to develop algorithms to calculate lifetime effective doses and collective doses to some hunters in Sweden. Ten hunters and their family members were randomly selected from each of the three most contaminated counties in Sweden (Västernorrland, Uppsala, Gävleborg) using the register for hunting weapons from the Police Authority in 1985. Hence, this design can be regarded as a closed cohort only including hunters and their family members living in these three counties at the time of the accident. Statistics Sweden matched these individuals (n = 85) with their dwelling coordinates onto the digital map produced by the Swedish Radiation Safety Authority after aerial measurements of 137Cs (kBq m-2). Internal effective doses were estimated using aggregated transfer factors from ground deposition to in-vivo body concentration for 134Cs and 137Cs in hunters (Bq kg-1). External effective doses were also calculated on the dwelling coordinate for 134Cs, 137Cs and short-lived nuclides in these three counties. Annual effective doses for external and internal doses were then cumulated up to a life expectancy of 80 years for men and 84 years for women, respectively. The total lifetime effective doses to the members of the hunter families in this cohort were on average 8.3 mSv in Västernorrland, 4.7 mSv in Uppsala and 4.1 mSv in Gävleborg. The effective dose to men were about 40% higher than in women. In all counties the internal dose was about 75% of the total lifetime effective dose. The collective dose for all hunters with family members, in total about 44,000 individuals, in these three counties could be approximated at about 256 manSv. This study shows it is possible to use register data to develop algorithms for calculating lifetime effective dose commitments for hunters with relatively accuracy.

Total cancer incidence in relation to 137Cs fallout in the most contaminated counties in Sweden after the Chernobyl nuclear power plant accident: a register-based study.

OBJECTIVES: To determine the total cancer incidence in relation to a 5-year exposure to caesium-137 (137Cs) from the 1986 Chernobyl nuclear power plant accident. METHODS: A closed cohort was defined as all individuals living in the three most contaminated counties in mid-Sweden in 1986. Fallout of 137Cs was retrieved as a digital map from the Geological Survey of Sweden, demographic data from Statistics Sweden, and cancer diagnosis from the National Board of Health and Welfare. Individuals were assigned an annual 137Cs exposure based on their place of residence (1986-1990), from which 5-year cumulative 137Cs exposures were calculated, accounting for the physical decay of 137Cs and changing residencies. HRs were adjusted for age, sex, rural/non-rural residence and pre-Chernobyl total cancer incidence. RESULTS: The 734 537 people identified were categorised by exposure: the first quartile was low exposure (0.0-45.4 kBq/m2), the second and third quartiles were intermediate exposure (45.41-118.8 kBq/m2), and the fourth quartile was the highest exposure (118.81-564.71 kBq/m2). Between 1991 and 2010, 82 495 cancer cases were registered in the 3 counties. Adjusted HRs (95% CI) were 1.03 (1.01 to 1.05) for intermediate exposure and 1.05 (1.03 to 1.07) for the highest exposure compared to the reference exposure. CONCLUSIONS: We found a small overall exposure-response pattern of the total cancer incidence related to 137Cs after adjustment for age, sex, rural residence and pre-Chernobyl cancer incidence.

Cancer incidence in northern Sweden before and after the Chernobyl nuclear power plant accident.

Sweden received about 5 % of the total release of (137)Cs from the Chernobyl nuclear power plant accident in 1986. The distribution of the fallout mainly affected northern Sweden, where some parts of the population could have received an estimated annual effective dose of 1-2 mSv per year. It is disputed whether an increased incidence of cancer can be detected in epidemiological studies after the Chernobyl nuclear power plant accident outside the former Union of Soviet Socialist Republics. In the present paper, a possible exposure-response pattern between deposition of (137)Cs and cancer incidence after the Chernobyl nuclear power plant accident was investigated in the nine northernmost counties of Sweden (2.2 million inhabitants in 1986). The activity of (137)Cs from the fallout maps at 1986 was used as a proxy for the received dose of ionizing radiation. Diagnoses of cancer (ICD-7 code 140-209) from 1980 to 2009 were received from the Swedish Cancer Registry (273,222 cases). Age-adjusted incidence rate ratios, stratified by gender, were calculated with Poisson regression in two closed cohorts of the population in the nine counties 1980 and 1986, respectively. The follow-up periods were 1980-1985 and 1986-2009, respectively. The average surface-weighted deposition of (137)Cs at three geographical levels; county (n = 9), municipality (n = 95) and parish level (n = 612) was applied for the two cohorts to study the pre- and the post-Chernobyl periods separately. To analyze time trends, the age-standardized total cancer incidence was calculated for the general Swedish population and the population in the nine counties. Joinpoint regression was used to compare the average annual percent change in the general population and the study population within each gender. No obvious exposure-response pattern was seen in the age-adjusted total cancer incidence rate ratios. A spurious association between fallout and cancer incidence was present, where areas with the lowest incidence of cancer before the accident coincidentally had the lowest fallout of (137)Cs. Increasing the geographical resolution of exposure from nine county averages to 612 parish averages resulted in a two to three times higher value of variance in the regression model. There was a secular trend with an increase in age-standardized incidence of cancer in both genders from 1980 to 2009, but significant only in females. This trend was stronger and statistically significant for both genders in the general Swedish population compared to the nine counties. In conclusion, using both high quality cancer registry data and high resolution exposure maps of (137)Cs deposition, it was not possible to distinguish an effect of (137)Cs on cancer incidence after the Chernobyl nuclear power plant accident in Sweden.

Installation of mechanical ventilation in a horse stable: effects on air quality and human and equine airways.

OBJECTIVES: To examine the effects of installing a mechanical ventilation system at a riding-school stable on indoor air quality and human and horse airways. METHODS: The intervention was the installation of mechanical ventilation in a riding-school stable. Carbon dioxide (CO2), ammonia, particles, horse allergen, microorganisms and endotoxins were measured in the stable. The stable-workers and riding-students completed a questionnaire and underwent the following tests: analysis of nasal lavage for inflammation biomarkers; levels of exhaled nitrogen oxide (NO); measurements of daily peak-expiratory flow (PEF). The horses were examined clinically by airway endoscopy and bronchoalveolar lavage (BAL) and were analysed for cytology and biomarkers. RESULTS: Levels of CO2 were nearly halved and airborne horse allergen levels were markedly reduced (5-0.8 kU/m3) after the intervention. A decreased level of ultrafine particles was observed (8000-5400 particles/cm3) after the intervention, while total and respirable dust levels were mainly unchanged (200 and 130 µg/m3). Levels of microorganisms in surface samples decreased following the intervention, whereas airborne microorganisms and endotoxin increased. There was no significant change in human symptoms, PEF-variability, exhaled NO or inflammatory biomarkers in the nasal lavage. In horses, the mean score of lower airway mucus was significantly reduced together with the mean level of expression of interleukin-6 mRNA in BAL cells after the intervention. CONCLUSIONS: The installation of a mechanical ventilation system resulted in an increased air exchange rate, as demonstrated by reduced levels of CO2, ammonia, ultrafine particles and horse allergen. There was no significant clinical effect on human airways, but there was a tendency for reduced inflammation markers. The results on the horses may indicate less impact on their airways after the intervention.

Influence of horse stable environment on human airways.

BACKGROUND: Many people spend considerable amount of time each day in equine stable environments either as employees in the care and training of horses or in leisure activity. However, there are few studies available on how the stable environment affects human airways. This study examined in one horse stable qualitative differences in indoor air during winter and late summer conditions and assessed whether air quality was associated with clinically detectable respiratory signs or alterations to selected biomarkers of inflammation and lung function in stable personnel. METHODS: The horse stable environment and stable-workers (n = 13) in one stable were investigated three times; first in the winter, second in the interjacent late summer and the third time in the following winter stabling period. The stable measurements included levels of ammonia, hydrogen sulphide, total and respirable dust, airborne horse allergen, microorganisms, endotoxin and glucan. The stable-workers completed a questionnaire on respiratory symptoms, underwent nasal lavage with subsequent analysis of inflammation markers, and performed repeated measurements of pulmonary function. RESULTS: Measurements in the horse stable showed low organic dust levels and high horse allergen levels. Increased viable level of fungi in the air indicated a growing source in the stable. Air particle load as well as 1,3-beta-glucan was higher at the two winter time-points, whereas endotoxin levels were higher at the summer time-point. Two stable-workers showed signs of bronchial obstruction with increased PEF-variability, increased inflammation biomarkers relating to reported allergy, cold or smoking and reported partly work-related symptoms. Furthermore, two other stable-workers reported work-related airway symptoms, of which one had doctor's diagnosed asthma which was well treated. CONCLUSION: Biomarkers involved in the development of airway diseases have been studied in relation to environmental exposure levels in equine stables. Respirable dust and 1,3-beta-glucan levels were increased at winter stabling conditions. Some employees (3/13) had signs of bronchial obstruction, which may be aggravated by working in the stable environment. This study contributes to the identification of suitable biomarkers to monitor the indoor horse stable environment and the personnel. An improved management of the stable climate will be beneficial for the health of both stable workers and horses.