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Denna rapport är en del i ett projekt där det övergripande syftet är att bättre förstå hur registerdata kan användas för att förebygga allvarliga olyckor i arbetslivet. 

Aims: To study the importance of decreasing tobacco smoking on the occurrence of larynx cancer in men and women.

Methods: The incidence rates of larynx cancer in the Swedish population between 1970 and 2021 were retrieved from the Swedish Cancer Register for ages 50–84 years, stratified for sex, age and calendar year. Data on the population’s smoking habits was retrieved from surveys and from taxation on the sale of cigarettes. The occurrence of larynx cancer was compared to smoking habits, sex and age. The time trends were compared between larynx and lung cancer.

Results: Over the years, Swedish men and women have had different smoking habits, especially older persons during the 1970s. In 1963, the prevalence of current smokers in women 50–69 years was 11%, while it was 46% in men. Around 2020, less than 10% of men and women in all age groups were current smokers. However, men had higher incidence rates of larynx cancer than women, even when their smoking habits were similar. For example, men and women 60–64 years of age in 2017–2021 had similar smoking habits during their life but the relative risk of larynx cancer in men compared to women was 3.3 (95% CI 1.7–4.8). However, pipe smoking was much more common in men.

Conclusions: The study indicates that other causes than cigarette smoking have an impact on the occurrence of larynx cancer in Sweden. Pipe smoking and occupational exposure to carcinogenic materials such as asbestos may be underlying causes of the difference in cancer risk between Swedish men and women.

Sammanfattning

En analys av arbetsskador som ersatts av yrkesskadeförsäkringen mellan 1960–1975 visar att

- Minskningen av antalet dödsolyckor (från ca 360 till ca 200 per år) beror på förebyggande åtgärder men också på att färre personer arbetar i miljöer där risken för en sådan skadehändelse är hög.

- Skadehändelser som orsakat invaliditet följer ett annat mönster än dödsolyckorna både när det gäller om de minskar eller ökar, vilka näringsgrenar som är mest drabbade och vilka orsaker som vållat skadan.

- Fördelningen av orsaker till dödsolyckor är idag likartad som under 1960–75, men incidensen var då cirka 9 gånger högre.

- Risken för en dödsolycka hade inget tydligt samband med hur många personer som arbetade hos arbetsgivaren. Idag är risken för en dödsolycka i arbetet betydligt högre i små företag, men då ingår också egenföretagare i statistiken.

- Trots att man samlat in en ganska omfattande och noggrann statistik på likartat sätt under perioden 1960–75 så saknar årsrapporterna en tolkning av vilka förebyggande åtgärder eller andra förhållanden som kan ha påverkat förekomsten av skadehändelserna.

- Dödsolyckor i samband med arbetet eller i samband med färd till arbetet har minskat i ungefär lika stor omfattning. Trenderna för antalet dödsolyckor i vägtrafiken under perioden 1960–75 har inte minskat på samma sätt.

- Att enbart förlita sig på statistik över dödsolyckor för att bedöma förekomsten av allvarliga skadehändelser i arbetslivet är otillräckligt om man vill ha en uppfattning om vad som påverkar/påverkat riskerna. Förekomsten av skador som orsakar invaliditet drabbar många människor kan behöva förebyggas på annat sätt än dödsolyckor.

Background: The aim was to elucidate whether occupational airborne exposures increases asthma mortality.

Methods: The study comprised men in the Swedish construction industry who participated in health controls in 1971–1993. Exposure was assessed using a job-exposure matrix with focus on exposures in the mid-1970s. Mortality from asthma in 1987–2015 was compared between 147,101 workers exposed to occupational airborne exposures and 26,879 foremen, using underlying and contributory cause of death from the Swedish Cause of Death Register. Mortality was assessed as relative risk with 95% confidence intervals using Poisson regression models adjusting for age, smoking, body mass index, and calendar time.

Results: Among exposed workers, there were 82 deaths with asthma as the underlying cause and 212 deaths with asthma as the contributory cause vs. ten and 21 deaths in the controls. The asthma mortality based on the underlying and contributory cause was 1.92 (1.31–2.83) in relation to inorganic dust, 2.17 (1.47–3.20) in relation to fumes, 1.60 (1.04–2.47) in relation to gases, and 1.79 (1.09–2.96) in relation to wood dust. Using only the underlying cause of death showed similar mortality estimates, but with wider confidence intervals including unity.

Conclusions: Occupational airborne exposures increased the asthma mortality, underscoring the need for further reduction of the airborne occupational exposures. Workers with asthma should be given information about the effects of exposure and support to decrease exposure. The study shows the importance of using both contributing and underlying cause of death in studies assessing asthma mortality risk in relation to air pollutants.

Background: Contrary to leisure-time physical activity, high levels of occupational physical activity (OPA) have been linked to cardiovascular disease and mortality. Many occupations in the construction industry are known to have high levels of OPA.Aims This study investigated OPA and stroke mortality risk among 299 382 Swedish male construction workers.

Methods: OPA was derived from job titles and categorized as low, medium or high, and stroke mortality was ascertained via the Swedish National Cause of Death Register. The average follow-up was 24 years resulting in a total of 6.9 million person-years, during which 4606 participants died from stroke. Relative risks were estimated with robust Poisson regressions and adjusted for age, calendar year, body mass index and smoking.

Results: The relative risk for overall stroke mortality was higher in the medium and high OPA groups compared to the low OPA group [1.15 (1.04, 1.27) and 1.13 (1.04, 1.23), respectively], with no clear dose-response association. Age-stratified analyses showed that higher OPA increased stroke mortality risk in participants between 70 and 89 years. Participants with high versus low OPA had a higher risk of ischaemic stroke mortality [1.15 (1.01, 1.31)].

Conclusions: Construction workers with high OPA have a slight increase in overall stroke mortality, mainly after retirement. Contrary to leisure-time physical activity, high levels of occupational physical activity have been linked to an increased risk of cardiovascular disease and mortality. Construction workers in this study with medium and high occupational physical activity had higher stroke mortality than those with low occupational physical activity. However, there was no difference in stroke mortality between those with high and medium occupational physical activity.

Objective: This paper discusses the failure and success of society to decrease the adverse health effects of asbestos exposure on workers’ health in relation to scientific knowledge.

Methods: The findings are based on a narrative literature review.

Results: Early warnings of the adverse health effects of workplace exposure to asbestos were published already in the 1930s. Serious health effects, such as malignancies and fibrosis due to occupational asbestos exposure, were highlighted in major medical journals and textbooks in late 1960s. New technologies could detect also asbestos fibers in the lung of non-occupational exposed persons in the 1970s. The first bans for using asbestos came in the early 1970s, and more general bans by authorities came in the 1980s and continue until today.

Conclusions: The rather late recognition of adverse effects of asbestos exposure in the general population and measures to decrease the exposure through more general bans came rather late. However, the very strong measures such as general bans in many countries have been a success. A Swedish study showed that the general ban and other measures have decreased the risk of malignancies due to occupational exposure. The effect of the bans on adverse effects in the general population has yet to be studied. Analysis of fibers in the lungs of persons born after the bans could be an efficient method.

Background: Oil refinery workers are exposed to benzene, which is a well-known cause of leukaemia, but results on leukaemia in oil refinery workers have been mixed, and the data on workers’ exposure is limited. Oil refinery workers are also exposed to asbestos and several studies have shown increased risk of mesothelioma.

Aim: The objective was to investigate cancer incidence, especially leukaemia, at low to moderate exposure to benzene in an update of a previous study of employees at three Swedish oil refineries.

Methods: Cancer incidence was followed up in 2264 men (1548 refinery operators) employed at three oil refineries in Sweden for at least one year. Job types and employment times were collected from complete company files. A retrospective assessment of the benzene exposure was performed by occupational hygienists in collaboration with the refineries using historic measurements as well as detailed information on changes in the industrial hygiene and technological developments. Cases of cancer were retrieved by a linkage with the Swedish Cancer Register through 35–47 years of follow-up and standardized incidence ratios (SIR) with 95% confidence intervals (CI) were calculated.

Results: In total, 258 tumors had occurred versus 240 expected (SIR 1.07; 95% CI 0.95–1.21). There were 10 cases of leukaemia, all in refinery operators (SIR 2.4; 95% CI 1.18–4.51). There were three cases of pleural mesothelioma, two of which in refinery operators. The mean estimated cumulative benzene exposure for the cases of leukaemia was 7.9 ppm-years (median 4.9, range 0.1–31.1). Discussion: The study suggests that low to moderate average cumulative benzene exposure increases the risk of leukaemia. Limitations include the modest number of cases and potential misclassification of exposure.

Conclusion: The present study indicated an increased risk of leukaemia in male oil refinery workers with low to moderate exposure to benzene.

Background: The objective is to estimate the importance of the decrease of smoking habits in Sweden for the occurrence of lung cancer.

Methods: The change in smoking habits in the general population was retrieved from surveys and on taxation of sale of cigarettes. We used data from the Swedish Cancer Register on incidence of lung cancer between 1970 and 2021, stratified for sex, age and cell type, and compared the occurrence overtime in ages between 40 and 84 years.

Results: The sale of cigarettes peaked in 1980 to 1800 cigarettes per person and decreased to 600 per person in 2021. The change in incidence rates of squamous cell cancer and other cell types varied over time, sex, and age in a pattern that partly seems to be explained by change in the prevalence of daily smokers. The incidence of adenocarcinoma was similar in men and women 1970–2021 and increased, e.g. for women and men 75–79 years of age from around 20 cases in early 1970s to around 120 cases per 100 000 person-years in the 2020s.

Conclusions: Our data indicate that the risk of lung cancer several years after smoking cessation is less favourable than previously studies have indicated. There is a similar increase in the incidence of adenocarcinoma in men and women which is hard to explain only with changing smoking habits. The change from non-filter to filter cigarettes in the 1960s–1970s may be a contributing factor.