Occupational risks for infection with influenza A and B: a national case-control study covering 1 July 2006-31 December 2019

OBJECTIVES

We investigated whether crowded workplaces, sharing surfaces and exposure to infections were factors associated with a positive test for influenza virus.

METHODS

We studied 11 300 cases with a positive test for influenza A and 3671 cases of influenza B from Swedish registry of communicable diseases. Six controls for each case were selected from the population registry, with each control being assigned the index date of their corresponding case. We linked job histories to job-exposure matrices (JEMs), to assess different transmission dimensions of influenza and risks for different occupations compared with occupations that the JEM classifies as low exposed. We used adjusted conditional logistic analyses to estimate the ORs for influenza with 95% CI.

RESULTS

The highest odds were for influenza were: regular contact with infected patients (OR 1.64, 95% CI 1.54 to 1.73); never maintained social distance (OR 1.51, 95% CI 1.43 to 1.59); frequently sharing materials/surfaces with the general public (OR 1.41, 95% CI 1.34 to 1.48); close physical proximity (OR 1.54, 95% CI 1.45 to 1.62) and high exposure to diseases or infections (OR 1.54, 95% CI 1.44 to 1.64). There were small differences between influenza A and influenza B. The five occupations with the highest odds as compared with low exposed occupations were: primary care physicians, protective service workers, elementary workers, medical and laboratory technicians, and taxi drivers.

CONCLUSIONS

Contact with infected patients, low social distance and sharing surfaces are dimensions that increase risk for influenza A and B. Further safety measures are needed to diminish viral transmission in these contexts.

Long-term risk factor control after acute coronary syndrome; results from the Swedish primary care cardiovascular database

Background

Most secondary prevention studies after acute coronary syndrome (ACS) have relatively short follow-up time, and less is known about long-term risk factor control in patients after ACS.

Purpose

We aimed to study and describe the long-term risk factor control, treatment adherence and outcome after ACS.

Methods

We identified 3765 patients (mean age 75 years, 40% women) with an incident ACS between 2006 and 2010 in the Swedish Primary Care Cardiovascular Database. All participants were followed from index ACS until 31 December 2014 or death. We annually recorded blood pressure, low density lipoprotein cholesterol (LDL-C), dispensed prescription of drugs, recurrent ACS, and death. Data were collected from electronic medical records at the primary care centres, the Swedish Prescribed Drug Register, the Swedish Patient Register, and the Cause of Death Register. We calculated annually proportion of days covered (PDC) for secondary prevention medication. PDC value of ≥80% was considered cut off for medication adherence.

Results

The median follow-up time was 4.8 years (min 1.8 and max 8.0). 1890 new ACS-events were recorded during the follow up; the annual incidence of recurrent ACS was 17.3%, 12.9%, 8.9%, 8.0%, 7.6%, 6.5%, 5.2%, and 5.0% (for year 1 to year 8 respectively). 1859 (49.4%) patients died during the follow up. The annual incidence of death was 19.9%, 7.9%, 7.1%, 8.3%, 7.9%, 8.2%, 6.7%, and 6.4% (for year 1 to year 8 respectively). The annual proportion of patients that achieved the blood pressure target <140/90 mm Hg was 57.8%, 60.9%, 62.7%, 63.3%, 64.9%, 63.1%, 62.4%, and 66.1% (for year 1 to year 8 respectively). The annual mean number of antihypertensive medications for each patient was 1.5, 1.3, 1.3, 1.3, 1.4, 1.4, 1.4, and 1.5 (for year 1 to year 8 respectively). The annual proportion of patients that achieved LDL-C <1.8 mmol/L was 23.1%, 21.7%, 19.8%, 18.2%, 15.7%, 19.6%, 18.3%, and 16.7% (for year 1 to year 8 respectively). The annual proportion of patients in treatment with statins was 55.3%, 57.5%, 58.7%, 59.2%, 63.0%, 63.7%, 64.1%, and 67.7% (for year 1 to year 8 respectively). The annual proportion of patients in treatment with acetylsalicylic acid was 79.6%, 76.4%, 76.2%, 78.9%, 78.3%, 79.2%, and 80.8% % (for year 1 to year 8 respectively). The annual proportion of patients in treatment with P2Y12-inhibitors was 24.3%, 7.2%, 5.4%, 6.0%, 7.2%, 8.1%, 7.9% and 8.2% (for year 1 to year 8 respectively).

Conclusion

This retrospective long-term real-world study from primary care demonstrates a large potential for improvement of risk factor control in patients after ACS. More specific, this study demonstrates underutilized treatment with antihypertensive medication and statins, while adherence to antiplatelet therapy was found to be high.

Funding Acknowledgement

Type of funding sources: Private company. Main funding source(s): Astra Zeneca

Occupational noise exposure and risk of incident stroke: a pooled study of five Scandinavian cohorts

OBJECTIVES

To investigate the association between occupational noise exposure and stroke incidence in a pooled study of five Scandinavian cohorts (NordSOUND).

METHODS

We pooled and harmonised data from five Scandinavian cohorts resulting in 78 389 participants. We obtained job data from national registries or questionnaires and recoded these to match a job-exposure matrix developed in Sweden, which specified the annual average daily noise exposure in five exposure classes (LAeq8h): <70, 70-74, 75-79, 80-84, ≥85 dB(A). We identified residential address history and estimated 1-year average road traffic noise at baseline. Using national patient and mortality registers, we identified 7777 stroke cases with a median follow-up of 20.2 years. Analyses were conducted using Cox proportional hazards models adjusting for individual and area-level potential confounders.

RESULTS

Exposure to occupational noise at baseline was not associated with overall stroke in the fully adjusted models. For ischaemic stroke, occupational noise was associated with HRs (95% CI) of 1.08 (0.98 to 1.20), 1.09 (0.97 to 1.24) and 1.06 (0.92 to 1.21) in the 75-79, 80-84 and ≥85 dB(A) exposure groups, compared with <70 dB(A), respectively. In subanalyses using time-varying occupational noise exposure, we observed an indication of higher stroke risk among the most exposed (≥85 dB(A)), particularly when restricting analyses to people exposed to occupational noise within the last year (HR: 1.27; 95% CI: 0.99 to 1.63).

CONCLUSIONS

We found no association between occupational noise and risk of overall stroke after adjustment for confounders. However, the non-significantly increased risk of ischaemic stroke warrants further investigation.

Increasing home-time after a first diagnosis of heart failure in Sweden, 20 years trends

AIMS

This study was performed to compare trends in home-time for patients with heart failure (HF) between those of working age and those of retirement age in Sweden from 1992 to 2012.

METHODS AND RESULTS

The National Inpatient Register (IPR) was used to identify all patients aged 18 to 84 years with a first hospitalization for HF in Sweden from 1992 to 2012. Information on date of death, comorbidities, and sociodemographic factors were collected from the Swedish National Register on Cause of Death, the IPR, and the longitudinal integration database for health insurance and labour market studies, respectively. The patients were divided into two groups according to their age: working age (<65 years) and retirement age (≥65 years). Follow-up was 4 years. In total, following exclusions, 388 775 patients aged 18 to 84 years who were alive 1 day after discharge from a first hospitalization for HF were included in the study. The working age group comprised 62 428 (16%) patients with a median age of 58 (interquartile range, 53-62) years and 31.2% women, and the retirement age group comprised 326 347 (84%) patients with a median age of 77 (interquartile range, 73-81) years and 47.4% women. Patients of working age had more home-time than patients of retirement age (83.8% vs. 68.2%, respectively), mainly because of their lower 4 year mortality rate (14.2% vs. 29.7%, respectively). Home-time increased over the study period for both age groups, but the increase levelled off for older women after 2007, most likely because of less reduction in mortality in older women than in the other groups.

CONCLUSIONS

This nationwide study showed increasing home-time over the study period except for women of retirement age and older for whom the increase stalled after 2007, mainly because of a lower mortality reduction in this group. Efforts to improve patient-related outcome measures specifically targeted to this group may be warranted.

Decreasing time on sick leave for patients with heart failure in Sweden during two decades

Background

Heart failure (HF) is increasing in people of working age in Sweden (1). Given high morbidity and reduced quality of life among HF patients (2, 3), working capacity could be greatly affected, however, studies are scarce.

Purpose

To determine trends in sick leave rates following a first hospitalization for HF in Sweden 1995–2015 compared to controls matched by age and sex.

Methods

In Sweden, people who cannot work receive sickness benefit. Sickness benefit pay days are registered by Statistics Sweden. We identified all patients aged 18–60 years with a first hospitalization for HF in Sweden 1995–2012 in the National Patient Register (NPR). For each case we selected 2 controls matched for age and sex. Cases and controls were split into age groups, &lt;45 years and 45–60 years. Age, sex and comorbidities were recorded. Paid sickness benefit days were recorded during the index year and the two subsequent years.

Results

A total of 24,677 cases and 65,923 controls were included, mean age for the younger and older age group 36.6 and 54.5 years, and proportion of women 35.3% and 23.8%, respectively. In 1995, the proportion of time on sickness benefit in patients &lt;45 years was on average 28%, decreasing to 15% in 2012, with corresponding estimates for patients 45–60 29% and 17%, shown by index year for cases and controls for patients &lt;45 years in Figure 1 and for patients 45–60 years in Figure 2.

Conclusion

Patients had a longer time on sick leave than controls over the study period. Time on sickness benefit initially declined over the course of the study period for both patients and controls, but the last years of the study period this decline stalled for both patients and controls.

Funding Acknowledgement

Type of funding sources: Public grant(s) – National budget only. Main funding source(s): This work was supported by the Swedish state under an agreement between the Swedish government and the County Councils Concerning Economic Support of Research and Education of Doctors [ALFGBG-717211, ALFGBG-433211, ALFGBG-725081]; the Swedish Heart and Lung Foundation [2013-0307, 2018-0419, 2018-0589]. Figure 1Figure 2

Blood pressure levels and risk of haemorrhagic stroke in patients with atrial fibrillation and anticoagulants: results from a primary care cohort with hypertension

Background

Haemorrhagic stroke (HS) is a serious condition that kills and debilitates many of those afflicted by it. Hypertension and oral anticoagulation (OAC) are independent risk factors for HS. Many patients with atrial fibrillation (AF) have hypertension and OAC. The concomitance of hypertension and OAC confers an even higher risk of haemorrhagic stroke, but less is known about the association between specific blood pressure levels and the risk of HS in patients with AF and OAC.

Purpose

To assess the risk of haemorrhagic stroke at different systolic blood pressure (SBP) levels in a primary care population with hypertension, AF and OAC.

Methods

We identified 3972 patients with hypertension, AF and OAC in a primary care database in southern Sweden. We followed patients from Jan 1, 2006 until a first event of HS, death, cessation of OAC or Dec 31, 2016. HS was defined as ICD-10 diagnosis codes: I60, I61, and I62. We analysed the association between SBP levels and HS by dividing SBP into five categories: &lt;130, 130–139, 140–159, 160–179 and ≥180 mmHg. We also fitted a spline curve to visualise the relationship between SBP and HS. Hazard ratios (HR) were calculated for the SBP categories with a Cox proportional hazards model. The 130–139 group was used as a reference in the model. We identified age, sex, previous stroke, platelet inhibitor treatment, alcohol abuse and smoking as possible confounders with a directed acyclic graph and included them as co-variates in the model.

Results

We identified 51 cases of HS during follow-up. In the categorical analysis of SBP, point estimates of HRs for HS increased gradually from the lowest SBP category to the 160–179 category. Only the 160–179 category had a significantly different HR (3.76, CI 1.56–9.04) than the reference 130–139 category, however. See Table 1. No other co-variates were significantly associated with HS. The spline curve, Figure 1, illustrates a significantly increased HR for HS in the 140–175 SBP range.

Conclusions

In this real-world primary care cohort with hypertension, AF and OAC, we found that SBP in the 160–179 mmHg range was significantly associated with an increased risk of haemorrhagic stroke. Our findings emphasise the importance of blood pressure control in this patient category.

Figure 1. Continuous and categorical SBP & HS risk

Funding Acknowledgement

Type of funding source: Public grant(s) – National budget only. Main funding source(s): The study was financed by grants from the Swedish state under the agreement between the Swedish government and the country councils, the ALF-agreement.

Increasing home-time for patients with heart failure in Sweden 1992–2008

Background

Heart failure (HF) reduces survival and is one of the most common causes of hospitalizations in the elderly, imposing a major economic burden on the health care system, with frequency of rehospitalizations often used in interventional and observational studies in patients with HF. Home-time is a novel end-point measuring time spent alive and out of hospital and is easier for both clinicians and patients to relate to. Given the advances in treatment of HF over the last decades we postulated that an increase in home-time would follow.

Purpose

To investigate whether home-time for patients with HF has changed over the last decades in Sweden and if home-time differs between patients of working age and those retired, or between men and women.

Methods

Patients aged 18–84 years with a first hospitalization for HF in Sweden between 1992 and 2008 were identified using the National Inpatient Register which was linked to the Swedish Cause of Death Register. Information on rehospitalizations and mortality was collected and followed over a time period of 4 years. The patients were divided into two age groups: (i) &lt;65 years and (ii) &gt;65 years. The cut off 65 years was chosen being the official age of retirement over the study period in Sweden.

Results

A total of 324,907 patients were included in this study, mean age 73.5 years (standard deviation 9.3). Only 15.6% were &lt;65 and 45.1% were women. In total, average home-time was 70.1% of the total follow up time, 2.1% of time was spent in hospital while, during a mean of 27.9% of the 4 year-period, patients were no longer alive. A small increase in home-time was observed over the study period. The older age group spent 67.7% at home compared with 83% in the younger group. After taking differences in mortality into account, the difference in home-time was no longer significant, with 92.7 and 95.8% home-time for the older and younger age groups, respectively. Over the entire study period older men had less home-time compared with older women. Since 1998 the reverse was true in younger men and women, where younger men had more home-time than younger women. Home-time increased for all subgroups over the study period with the most pronounced increase for younger men (see figure 1).

Conclusion

Home-time for patients in Sweden increased over the study period and the increase was more marked for younger patients, where men spent more time at home than women.

Figure 1

Funding Acknowledgement

Type of funding source: Public grant(s) – National budget only. Main funding source(s): The Swedish state (ALF), The Swedish Heart and Lung Foundation, Västra Götaland Region, The Göteborg Medical Society

Occupational exposure to dust and to fumes, work as a welder and invasive pneumococcal disease risk

Objectives

Occupational exposures to metal fumes have been associated with increased pneumonia risk, but the risk of invasive pneumococcal disease (IPD) has not been characterised previously.

Methods

We studied 4438 cases aged 20–65 from a Swedish registry of invasive infection caused by Streptococcus pneumoniae. The case index date was the date the infection was diagnosed. Six controls for each case, matched for gender, age and region of residency, were selected from the Swedish population registry. Each control was assigned the index date of their corresponding case to define the study observation period. We linked cases and controls to the Swedish registries for socioeconomic status (SES), occupational history and hospital discharge. We applied a job–exposure matrix to characterise occupational exposures. We used conditional logistic analyses, adjusted for comorbidities and SES, to estimate the OR of IPD and the subgroup pneumonia–IPD, associated with selected occupations and exposures in the year preceding the index date.

Results

Welders manifested increased risk of IPD (OR 2.99, 95% CI 2.09 to 4.30). Occupational exposures to fumes and silica dust were associated with elevated odds of IPD (OR 1.11, 95% CI 1.01 to 1.21 and OR 1.33, 95% CI 1.11 to 1.58, respectively). Risk associated with IPD with pneumonia followed a similar pattern with the highest occupational odds observed among welders and among silica dust exposed.

Conclusion

Work specifically as a welder, but also occupational exposures more broadly, increase the odds for IPD. Welders, and potentially others with relevant exposures, should be offered pneumococcal vaccination.

P5743Overweight and obesity in adolescent men in Sweden and risk of early stroke

Background

Increasing numbers of stroke cases in the young are reported in many countries, potentially at least partly due to rising rates of overweight and obesity. Most data on the effect of obesity on stroke is derived from middle aged populations; there is a comparative lack of information on the effect of excessive body weight in young people.

Purpose

We aimed to determine whether body mass index (BMI) at age 18 predicted early stroke events among men in Sweden.

Methods

Population-based Swedish cohort study of conscripts (n=1,668,921; mean age at baseline, 18.3 years) who enlisted during 1968–2005. Follow-up was done through linkage to the nationwide Swedish patient and death registries. Risk of a first hospitalization for stroke (any type) during follow-up (5–46 years) was calculated with Cox proportional hazards models. Objective baseline measures of fitness and cognition were included in the models in a second set of analyses.

Results

During follow-up there were 12,512 first hospitalizations for stroke (mean age at diagnosis, 48.5 (SD 9.4) years, maximum 64 years). Compared with men with BMI of 18.5 to 20.0 kg/m2, men with BMI 20 to <22.5 and 22.5 to <25.0 kg/m2 had hazard ratios (HR) of 1.06 (1.00–1.12) and 1.23 (1.14–1.31), respectively, for hospitalization for stroke, after adjustment for age, year of conscription, comorbidities at baseline, parental education, blood pressure, IQ, muscle strength, and fitness. Those with a BMI of ≥35 kg/m2 had an HR of 3.33 (2.46–4.51) for an event before the age of 65, compared to slim men. The multiple-adjusted risk per 1-unit increase in BMI was 1.07 (95% CI, 1.06–1.08).

Conclusion

We found a rise in risk of early hospitalisation for stroke detectable already at normal levels of body weight at age 18, and rising to more than 3-fold in the highest weight category. Given increasing levels of body weight, and prevalence of overweight, obesity, and severe obesity in young adults, the increased incidence of stroke in the young may potentially partly be explained by rising body weight, with an obvious potential for prevention.

P5297Body weight in adolescent men in Sweden and risk of an early acute coronary event

Background

To improve cardiovascular disease (CVD) prevention, knowledge of early key risk factors, especially those that are modifiable such as overweight and obesity, is essential.

Purpose

We aimed to determine whether body mass index (BMI) at age 18 predicted early acute coronary events among men in Sweden.

Methods

Population-based Swedish cohort study of conscripts (n=1,668,921; mean age at baseline, 18.3 years) who enlisted during 1968–2005. Follow-up was done through linkage to the nationwide Swedish patient- and death registries. Risk of an acute coronary event (hospitalization for acute myocardial infarction or coronary death) during follow-up (5–46 years) was calculated with Cox proportional hazards models. Objective baseline measures of fitness and cognition were included in the models in a second set of analyses.

Results

During follow-up there were 22,412 acute coronary events (mean age at diagnosis, 50.2 (SD 7.4) years, maximum 64 years). Compared with men with BMI of 18.5 to 20.0 kg/m2, men with BMI 20 to <22.5 and 22.5 to <25.0 kg/m2 had hazard ratios (HR) of 1.17 (1.12–1.43) and 1.51 (1.44–1.59), respectively, for an acute coronary event, after adjustment for age, year of conscription, comorbidities at baseline, parental education, blood pressure, IQ, muscle strength, and fitness. Those with a BMI of ≥35 kg/m2 had an HR of 3.47 (2.75–4.39) for an event before the age of 65. The multiple-adjusted risk per 1-unit increase in BMI was 1.10 (95% CI, 1.09–1.10).

Conclusion

We found a rise in risk of an early acute coronary event detectable already at normal levels of body weight at age 18, and rising to more than 3-fold in the highest weight category. Given increasing levels of body weight, and prevalence of overweight and obesity in young adults, the current decrease in coronary heart disease incidence in Sweden may flatten or even reverse in the near future.

Acknowledgement/Funding

The Swedish Heart and Lung Foundation [2015-0438]; the Swedish Research Council [2013-5187,2013-4236]