COVID-19: incidence and mortality in Sweden comparing all foreign-born to all Swedish-born individuals in different occupations in an unvaccinated cohort of year 2020.

OBJECTIVES: The aim was to analyse the incidence and mortality of COVID-19 in immigrants compared with Swedish born in inpatients and outpatient registers, respectively. METHODS: The study population included all persons 20-88 years of age living in Sweden, 31 December 2019, including 1 676 516 foreign-born persons and 6 037 151 Swedish-born persons. The outcome was clinical cases of COVID-19 with a positive PCR test (ICD-10 U07.01) or without a positive PCR test (U07.2) from 1 January to 31 December 2020. Persons 20-64 years of age were classified with occupational titles according to the Swedish Standard Classification of Occupations. Residing municipality of each individual was coded according to the Swedish Association of Local Authorities. Relative risks (RR) were calculated by sex in 5 years age bands using Swedish born as reference. Age-adjusted RRs (adj RR) with 95% CIs were calculated in a Poisson regression model. Rural municipalities were used as the reference category. RESULTS: Foreign born had consistently higher RRs in COVID-19, regardless of sex, with a peak in 50-69 years of age. Foreign born had a higher RR of death in COVID-19 above 50 years and 40 years of age in women and men, respectively. Among occupations, male drivers had the highest adj RR 4.37 (95% CI 3.45 to 5.54) and 5.09 (4.26 to 6.07) in outpatients and inpatients, respectively (U07.1). Persons living in commuting municipalities did not show any consistent increased risk for COVID-19. CONCLUSION: Foreign born have a higher risk of COVID-19 compared with Swedish-born individuals at any age and occupation before vaccination began in 2021.

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.

Sustainable Earnings among Immigrants, and the Role of Health Status for Self-Sufficiency: A 10-Year Follow-Up Study of Labour Immigrants and Refugees to Sweden 2000-2006.

This study aimed to investigate economic self-sufficiency for immigrants, and how health status affected self-sufficiency. The proportion of self-sufficiency during years 1-10 after receiving a residence permit is presented for all non-European labour immigrants (n = 1259) and refugees (n = 23,859), aged 18-54, who immigrated to Sweden 2000-2006, and compared to a control group of Swedish-born (n = 144,745). The risk of not being self-sufficient in year 10 was analysed with Cox regression models, and the results are presented as hazard ratios (HRs) with 95% confidence intervals (CIs). Moreover, the impact on the self-sufficiency of having a diagnosis from specialised health care during the first five years in Sweden was analysed. The results showed that half of the refugees and three-quarters of the labour immigrants were self-sufficient 10 years after residency. The adjusted risk of not being self-sufficient at year 10 was 80% higher among labour immigrants (HR = 1.8; CI = 1.6-2.0) and more than two-fold among refugees (HR = 2.7; CI = 2.6-2.8) compared to the Swedish-born. Having a diagnosis from specialised health care during the first five years in Sweden had an impact on self-sufficiency in all groups; however, the impact of having a diagnosis did not differ between refugees and Swedish-born. Measures must be taken to increase immigrants' work participation.

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.

Healthy migrant effect in the Swedish context: a register-based, longitudinal cohort study.

OBJECTIVES: Studies have found a 'healthy-migrant effect' (HME) among arriving migrants, that is, a better health status compared with others in the home country, but also in comparison with the population in the host country. The aims were to investigate whether the HME hypothesis is applicable to the Swedish context, that is, if health outcomes differed between a group of mainly labour migrants (Western migrants) and a group of mainly refugee/family reunion migrants (non-Western migrants) compared with the native Swedish population, and if there were any correlations between labour market attachment (LMA) and these health outcomes. DESIGN: Register-based, longitudinal cohort study. PARTICIPANTS: The cohort was defined on 31 December 1990 and consisted of all migrants aged 18-47 years who arrived in Sweden in 1985-1990 (n=74 954) and a reference population of native Swedes (n=1 405 047) in the same age span. They were followed for three consecutive 6-year periods (1991-1996, 1997-2002 and 2003-2008) and were assessed for five measures of health: hospitalisation for cardiovascular and psychiatric disorders, mortality, disability pension, and sick leave. RESULTS: Western migrants had, compared with native Swedes, lower or equal HRs for all health measures during all time periods, while non-Western migrants displayed higher or equal HRs for all health measures, except for mortality, during all time periods. Age, educational level, occupation and LMA explained part of the difference between migrants and native Swedes. High LMA was associated with higher HRs for cardiovascular disorders among Western migrants, higher HRs of psychiatric disorders among non-Western migrants and higher HRs of mortality among both migrant groups compared with native Swedes. CONCLUSIONS: There were indications of a HME among Western migrants, while less proof of a HME among non-Western migrants. Stratification for LMA and different migrant categories showed some interesting differences, and measurements of the HME may be inconclusive if not stratified by migrant category or other relevant variables.

Exposure to Upper Arm Elevation During Work Compared to Leisure Among 12 Different Occupations Measured with Triaxial Accelerometers.

Regarding prevention of neck and shoulder pain (NSP), unsupported arm elevation is one factor that should be taken into account when performing work risk assessment. Triaxial accelerometers can be used to measure arm elevation over several days but it is not possible to differentiate between supported and unsupported arm elevation from accelerometers only. Supported arm elevation is more likely to exist during sitting than standing. The aim of the study was to evaluate the use of whole workday measurements of arm elevation with accelerometers to assess potentially harmful work exposure of arm elevation, by comparing arm elevation at work with arm elevation during leisure, in a population with diverse work tasks, and to assess how the exposure parameters were modified when upper arm elevation during sitting time was excluded. The participants, 197 workers belonging to 12 occupational groups with diverse work tasks, wore triaxial accelerometers on the dominant arm, hip, and back for 1-4 days to measure arm elevation and periods of sitting. None of the groups were found to have higher exposure to arm elevation during work compared to leisure. Even though some occupations where known to have work tasks that forced them to work with elevated arms to a large extent. A high proportion of arm elevation derived from sitting time, especially so during leisure. When arm elevation during sitting time was excluded from the analysis, arm elevation was significantly higher at work than during leisure among construction workers, garbage collectors, manufacturing workers, and domestic cleaners. Together this illustrates that it is not suitable to use whole workday measurments of arm elevation with accelerometer as a sole information source when assessing the risk for NSP due to arm elevation. Information on body posture can provide relevant contextual information in exposure assessments when it is known that the potential harmful exposure is performed in standing or walking.

Personal and demographic factors and change of subjective indoor air quality reported by school children in relation to exposure at Swedish schools: a 2-year longitudinal study.

This paper studies changes in subjective indoor air quality (SIAQ) among school children and relates these data to repeated exposure measurements during a two-year follow-up period. Data on SIAQ and demographic information were gathered by a questionnaire sent to 1476 primary and secondary school pupils in 39 randomly selected schools at baseline and after two years (follow-up). Exposure measurements were applied after questionnaire data were collected at baseline and follow-up in approximately 100 classrooms. The arithmetic mean values for baseline and follow-up were: for indoor air temperature 23.6°C and 21.8°C and for outdoor air flow rate 5.4 L/s and 7.9L/s. Older children, those with atopy at baseline, and those in larger schools reported impaired SIAQ during follow-up. Installation of new ventilation systems, higher personal air flow rate and air exchange rate, and better illumination were associated with improved SIAQ. Higher CO2 levels were associated with impaired SIAQ. In conclusion, sufficient ventilation and illumination in classrooms are essential for the perception of good indoor air quality.

Work and health among immigrants and native Swedes 1990-2008: a register-based study on hospitalization for common potentially work-related disorders, disability pension and mortality.

BACKGROUND: There are many immigrants in the Swedish workforce, but knowledge of their general and work-related health is limited. The aim of this register-based study was to explore whether documented migrant residents in Sweden have a different health status regarding receipt of a disability pension, mortality and hospitalization for lung, heart, psychiatric, and musculoskeletal disorders compared with the native population, and if there were variations in relation to sex, geographical origin, position on the labor market, and time since first immigration. METHODS: This study included migrants to Sweden since 1960 who were 28-47 years old in 1990, and included 243 860 individuals. The comparison group comprised a random sample of 859 653 native Swedes. These cohorts were followed from 1991 to 2008 in national registers. The immigrants were divided into four groups based on geographic origin. Hazard ratios for men and women from different geographic origins and with different employment status were analyzed separately for the six outcomes, with adjustment for age, education level, and income. The influence of length of residence in Sweden was analyzed separately. RESULTS: Nordic immigrants had increased risks for all investigated outcomes while most other groups had equal or lower risks for those outcomes than the Swedes. The lowest HRs were found in the EU 15+ group (from western Europe, North America, Australia and New Zealand). All groups, except Nordic immigrants, had lower risk of mortality, but all had higher risk of disability pension receipt compared with native Swedes. Unemployed non-Nordic men displayed equal or lower HRs for most outcomes, except disability pension receipt, compared with unemployed Swedish men. A longer time since first immigration improved the health status of men, while women showed opposite results. CONCLUSIONS: Employment status and length of residence are important factors for health. The contradictory results of low mortality and high disability pension risks need more attention. There is great potential to increase the knowledge in this field in Sweden, because of the high quality registers.

A longitudinal study of sick building syndrome among pupils in relation to microbial components in dust in schools in China.

There are few longitudinal studies on sick building syndrome (SBS), which include ocular, nasal, throat, and dermal symptoms, headache, and fatigue. We studied the associations between selected microbial components, fungal DNA, furry pet allergens, and incidence and remission of SBS symptoms in schools in Taiyuan, China. The study was based on a two-year prospective analysis in pupils (N=1143) in a random sample of schools in China. Settled dust in the classrooms was collected by vacuum cleaning and analyzed for lipopolysaccharide (LPS), muramic acid (MuA), and ergosterol (Erg). Airborne dust was collected in Petri dishes and analyzed for cat and dog allergens and fungal DNA. The relationship between the concentration of allergens and microbial compounds and new onset of SBS was analyzed by multi-level logistic regression. The prevalence of mucosal and general symptoms was 33% and 28%, respectively, at baseline, and increased during follow-up. At baseline, 27% reported at least one symptom that improved when away from school (school-related symptoms). New onset of mucosal symptoms was negatively associated with concentration of MuA, total LPS, and shorter lengths of 3-hydroxy fatty acids from LPS, C14, C16, and C18. Onset of general symptoms was negatively associated with C18 LPS. Onset of school-related symptoms was negatively associated with C16 LPS, but positively associated with total fungal DNA. In general, bacterial compounds (LPS and MuA) seem to protect against the development of mucosal and general symptoms, but fungal exposure measured as fungal DNA could increase the incidence of school-related symptoms.

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.

Hearing status among cabin crew in a Swedish commercial airline company.

PURPOSE: To study hearing loss in commercial airline cabin crew (CC). METHODS: Totally 155 male and 781 female CC (n = 936) in a Swedish airline company underwent repeated audiometric tests during 1974-2005. The last test was used to study hearing loss. The mean test values at 3, 4, 6 kHz were used for the ear with worse hearing loss. Data were compared with a Swedish population (n = 603) who were not occupationally exposed to noise. Equivalent noise levels (Leq) were measured in different aircraft. RESULTS: Leq was 78-84 dB (A), maximum A-weighted exposure was 114 dB. Median values for all ages were close to the reference group. No association was found between years of employment and hearing loss, when adjusting for age and gender by multiple logistic regression analysis. CONCLUSION: Cabin crew are exposed to equivalent noise levels below the current Swedish occupational standard, and have normal age-matched hearing threshold levels.

Traffic-generated air pollution and myocardial infarction.

BACKGROUND: Although long-term air pollution exposure has been linked to cardiovascular mortality, data on incidence and nonfatal coronary disease are limited and inconclusive. The aim of this study was to investigate the association between long-term residential exposure to air pollution from traffic and the risk of nonfatal and fatal myocardial infarction. METHODS: The records of all individuals aged 15 to 79 with a first event of myocardial infarction in Stockholm County during 1985 to 1996 were retrieved from a registry. Population controls were randomly selected from the study base stratified by age, sex, and calendar year. Individual socioeconomic data and home addresses were obtained from population censuses 1970 to 1995. Annual air pollution exposure was assessed by dispersion modeling at the home addresses of 24,347 cases and 276,926 controls. RESULTS: Five-year average traffic-generated air pollution exposure corresponding to a difference in nitrogen dioxide from the fifth to the 95th percentile (31 microg/m) was associated with an odds ratio for fatal myocardial infarction adjusted for age, sex, calendar year, and socioeconomic status of 1.23 (95% confidence interval [CI] = 1.15-1.32). The corresponding odds ratio was 2.54 (1.96-3.29) among those with least expected misclassification of true individual exposure (those who did not move between censuses). Different time-windows and analyses of other pollutants including carbon monoxide and particles less than 10 mum in diameter (PM10) produced weaker associations. There was no increased risk for nonfatal myocardial infarction (ORs 0.94-0.98). CONCLUSIONS: Long-term exposure to traffic-generated air pollution is associated with fatal myocardial infarction but not with nonfatal infarction.

Left main coronary artery stenosis no longer a risk factor for early and late death after coronary artery bypass surgery--an experience covering three decades.

OBJECTIVE: To analyse early and late mortality after coronary artery bypass grafting (CABG) in patients with and without left main coronary artery (LMCA) stenosis during the 30-year period 1970-1999. METHODS: A total of 1888 of 10,647 patients (18%) who underwent a first isolated CABG at the Karolinska Hospital in Stockholm, Sweden, during 1970-1999 had significant left main coronary artery stenosis. The Swedish National Cause of Death Register was used to determine mortality up to five years after the operation. RESULTS: The proportion of patients with LMCA stenosis of all CABG patients increased from 7% during the 1970s to 26% in 1999. During 1970-1984 early mortality was 5.8% in patients with LMCA stenosis compared with 1.5% in patients without LMCA stenosis (odds ratio (OR) 3.7 (95% confidence interval (CI) 1.8-7.6)). The corresponding rates during 1995-1999 were 2.0% versus 2.2% (OR 0.8 (95% CI 0.5-1.5)), respectively. The increased risk of early death in patients with LMCA stenosis was neutralised in males during 1985-1994 and in females during 1995-1999. Five-year survival in males was 88% after operations performed during 1994-1999 compared with 82% after CABG performed during 1970-1984. Five-year mortality, exclusive of early deaths, during 1970-1984 was higher in patients with LMCA stenosis (12.8%) than in those without (8.4%) (relative risk 1.7 (95% CI 1.1-2.5)). An increased risk of late mortality in patients with LMCA stenosis was neutralised in males during 1985-1994 and in females during 1995-1999. CONCLUSIONS: During 1970-1999 there was a decrease of early and five-year mortality in patients with LMCA stenosis after CABG despite increase of patient age and risk factors. There were gender differences so that the risk of death in patients with compared with in those without LMCA stenosis was neutralised in males during 1985-1994 and in females during 1994-1999. The continuous decline of mortality during three decades most likely reflects improvement of the peri- and postoperative management of patients undergoing CABG during this period.