Myocardial infarction and cardiac regulation in relation to vibration exposure

The purpose of this thesis was to assess the possible risk of myocardial infarction in work entailing exposure to vibration, and to study whether there is any relation between short-term exposure to vibration and cardiac regulation. Epidemiological methods were applied to investigate a possible association between occupational exposure to vibration and myocardial infarction. Two study populations were used; one case-control study (n=475) and one cohort of iron-ore miners in Kiruna and Malmberget, Sweden (n=13621). In the former, the cases were first-time myocardial infarction patients and the controls were selected to match for sex, age and hospital catchment area. Job-exposure matrixes for vibration were established for both the case-control study and the cohort study. In order to study acute effects on cardiac regulation, an experimental study was conducted on healthy subjects (n=20) who were exposed to hand-arm vibration exclusively and in combination with exposure to noise. The effect on the autonomic balance was measured by heart rate-variability. In the case-control study, an increased risk of contracting myocardial infarction was found among occupations entailing vibration exposure. The results from the cohort show an increased risk of myocardial infarction mortality compared to a reference population. The increment was higher for those younger than 60 years. Relative risks for myocardial infarction mortality increased with increasing exposure to vibration in the group at working-age and the increased risk remained after adjusting for exposure to dust. In the experimental study, exposure to hand-arm vibration was found to acutely affect the autonomic nervous system as the total heart-rate variability decreased during exposure to hand-arm vibration. To conclude: work entailing exposure to vibration is a risk factor for myocardial infarction, increased myocardial infarction mortality attributed to exposure to vibration seems to be mainly observed at working-age, and exposure to hand-arm vibration acutely decreases heart-rate variability and thus affects heart-rate regulation

Hälsorelaterad miljöövervakning. : Cancerframkallande ämnen i tätortsluft i Umeå 2021

Undersökningen kartlägger allmänbefolkningens exponering via luften för vissa cancerframkallande ämnen (bensen, 1,3-butadien, formaldehyd) och kvävedioxid. Undersökningen genomfördes i centrala Umeå under hösten 2021, och inkluderade totalt 40 slumpvis utvalda personer i åldrarna 20-60 år.Mätningarna upprepades på 20 personer. Utöver de personburna mätningarna genomfördes även stationära mätningar på två platser utomhus. Svarsfrekvensen var 61% och medelåldern var 41 år. Medianhalten för personburna mätningar av bensen och 1,3-butadien var 0,57 µg/m3respektive 0,03µg/m3 vilket är lägre än tidigare mätomgångar i Umeå. Motsvarande medianhalt för formaldehyd var 8,3µg/m3, där halterna var högre bland de som bodde i radhus eller villa jämfört med lägenhet. Medianhalten för de personburna mätningarna av kvävedioxid var 7,6 µg/m3, vilket var i samma storleksordning uppmätt i Umeå 2001, men lägre än övriga mättillfällen. Ingen signifikant skillnad i halter för något av ämnena kunde påvisas mellan män och kvinnor.De stationära mätningarna genomfördes som veckomätningar vid kommunens urbana bakgrundsstationsamt vid en gatustation. Medianhalt av bensen, 1,3-butadien, formaldehyd samt kvävedioxid vid respektive mätstation var samtliga lägre jämfört med tidigare å

Hälsorelaterad miljöövervakning. : Cancerframkallande ämnen i tätortsluft i Umeå 2021

Undersökningen kartlägger allmänbefolkningens exponering via luften för vissa cancerframkallande ämnen (bensen, 1,3-butadien, formaldehyd) och kvävedioxid. Undersökningen genomfördes i centrala Umeå under hösten 2021, och inkluderade totalt 40 slumpvis utvalda personer i åldrarna 20-60 år.Mätningarna upprepades på 20 personer. Utöver de personburna mätningarna genomfördes även stationära mätningar på två platser utomhus. Svarsfrekvensen var 61% och medelåldern var 41 år. Medianhalten för personburna mätningar av bensen och 1,3-butadien var 0,57 µg/m3respektive 0,03µg/m3 vilket är lägre än tidigare mätomgångar i Umeå. Motsvarande medianhalt för formaldehyd var 8,3µg/m3, där halterna var högre bland de som bodde i radhus eller villa jämfört med lägenhet. Medianhalten för de personburna mätningarna av kvävedioxid var 7,6 µg/m3, vilket var i samma storleksordning uppmätt i Umeå 2001, men lägre än övriga mättillfällen. Ingen signifikant skillnad i halter för något av ämnena kunde påvisas mellan män och kvinnor.De stationära mätningarna genomfördes som veckomätningar vid kommunens urbana bakgrundsstationsamt vid en gatustation. Medianhalt av bensen, 1,3-butadien, formaldehyd samt kvävedioxid vid respektive mätstation var samtliga lägre jämfört med tidigare å

Coarse Fraction Particle Matter and Exhaled Nitric Oxide in Non-Asthmatic Children

Coarse particle matter, PMcoarse, is associated with increased respiratory morbidity and mortality. The aim of this study was to investigate the association between short-term changes in PMcoarse and sub-clininal airway inflammation in children. Healthy children aged 11 years from two northern Swedish elementary schools underwent fraction of exhaled nitrogen oxide (FENO) measurements to determine levels of airway inflammation twice weekly during the study period from 11 April–6 June 2011. Daily exposure to PMcoarse, PM2.5, NO2, NOx, NO and O3 and birch pollen was estimated. Multiple linear regression was used. Personal covariates were included as fixed effects and subjects were included as a random effect. In total, 95 children participated in the study, and in all 493 FENO measurements were made. The mean level of PMcoarse was 16.1 μg/m3 (range 4.1–42.3), and that of O3 was 75.0 μg/m3 (range: 51.3–106.3). That of NO2 was 17.0 μg/m3 (range: 4.7–31.3), NOx was 82.1 μg/m3 (range: 13.3–165.3), and NO was 65 μg/m3 (range: 8.7–138.4) during the study period. In multi-pollutant models an interquartile range increase in 24 h PMcoarse was associated with increases in FENO by between 6.9 ppb (95% confidence interval 0.0–14) and 7.3 ppb (95% confidence interval 0.4–14.9). PMcoarse was associated with an increase in FENO, indicating sub-clinical airway inflammation in healthy children

Thermal perception thresholds among workers in a cold climate

PURPOSE: To investigate whether exposure to cold could influence the thermal perception thresholds in a working population. METHODS: This cross-sectional study was comprised of 251 males and females and was carried out at two mines in the northern part of Norway and Sweden. The testing included a baseline questionnaire, a clinical examination and measurements of thermal perception thresholds, on both hands, the index (Digit 2) and little (Digit 5) fingers, for heat and cold. RESULTS: The thermal perception thresholds were affected by age, gender and test site. The thresholds were impaired by experiences of frostbite in the fingers and the use of medication that potentially could affect neurosensory functions. No differences were found between the calculated normative values for these workers and those in other comparative investigations conducted in warmer climates. CONCLUSIONS: The study provided no support for the hypothesis that living and working in cold climate will lead to impaired thermal perception thresholds. Exposure to cold that had caused localized damage in the form of frostbite was shown to lead to impaired thermal perception

Introducing a new design of digital tool to increase vibration risk assessments : challenges with education-based interventions

Objectives. This study aimed to investigate whether introducing a digital risk assessment tool, the Swedish National Vibration Database, would increase the number of risk assessments on hand–arm and whole-body vibration. Employer and safety representatives from companies where vibration exposure is common were invited. Methods. Of the 2953 invited companies, 1916 were selected for educational intervention and the remaining 1037 companies served as a control group with no intervention. For the educational intervention, participating companies were further divided into two groups (group A, n = 26; group B, n = 47) that both received information regarding risk assessment, but group B was also informed about the digital tool. Both groups answered a questionnaire on risk assessment before the intervention and at the follow-up, 6 months later; the control group received the same questionnaire but no education (group C, n = 22). Results. Of the invited companies, only 2% chose to participate and 7% at follow-up. Seventy-eight percent of the participants had made some kind of risk assessment of vibration at follow-up. Conclusion. Due to the low participation rate among invited companies, this study is not able to draw any conclusions on whether the digital tool can be used to increase the number of risk assessments

Manifestations of cold sensitivity : a case series

Objectives: To characterise cold sensitivity using a semi-structured interview, physical examination, thermal quantitative sensory testing (QST), and laser speckle contrast analysis (LASCA). Methods: Eight women and four men, ages 22–74, with cold sensitivity were interviewed andexamined by an occupational physician. Thermal perception thresholds were established using QST, on the pulp of the index and little finger of the most affected hand. Skin perfusion in the dorsum of the hand was measured using LASCA, at baseline, after two-minute 12°C water immersion, and during rewarming. Results: The physical examination yielded few findings indicative of vascular or neurosensory pathology. One subject (8%) had impaired thermal perception thresholds. LASCA at baseline showed absent proximal-distal perfusion gradients in six subjects (50%), and a dyshomogeneousperfusion pattern in five (42%). Perfusion on a group level was virtually unchanged by cold stress testing (median 52.5 PU; IQR 9.0 before versus 51.3 PU; IQR 27.2 afterwards). Conclusions: Physical examination and thermal QST offered little aid in diagnosing cold sensitivity, which challenges the neurosensory pathophysiological hypothesis. LASCA indicated disturbances in microvascular regulation and could prove a useful tool in future studies on cold sensitivity