| 1. |
- Raza, Wasif, 1971-
(författare)
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Impacts of Active Transport on Health : with a focus on physical activity, air pollution, and cardiovascular disease
- 2021
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Background: There are increasing number of health impact assessment studies investigating the health effects by transferring trips made by motorised transport to active commuting; however, air pollution exposure during active commuting and its impact on health has been less thoroughly assessed. It is furthermore uncertain whether there is any interaction effect between air pollution and physical activity for the risk of cardiovascular diseases. The overall aim of the thesis was to improve the knowledge base for assessments of the total impact on health of a mode shift resulting in both increased physical activity and increased air pollution exposure, especially regarding combined effects on cardiovascular risks.Methods: The thesis is based on four studies. In Study I, methodological issues related to the assessment of air pollution in previous studies on the health impact of changes in transport mode were critically reviewed. In Study II, the effect of leisure time and active commuting physical activity, on chronic diseases was quantified by conducting a random-effect meta-analysis. In two prospective cohort studies, participants of the Västerbotten Intervention Programme living in the Umeå region were studied to assess the impact as well as interaction effect of physical activity and air pollution on the incidence (Study III) and recurrence (Study IV) of cardiovascular diseases.Results: In previous studies on the health impact of changes in transport mode, there was a large methodological discrepancy between studies due to different assumptions for air pollution exposure assessments in general populations and commuters as well as methods for estimation of impacts. Randomeffect meta-analyses showed a beneficial effect of leisure time physical activity and active commuting on morbidity among individuals performing these activities at the minimum level of physical activity recommended by WHO, equivalent to 11.25 MET-hours per week. Beneficial effects of exercise on firstincident ischemic heart disease (IHD) were observed among individuals with high residential PM10/PM2.5 concentrations, but not among individuals with low concentrations. Adverse effects associated with high residential PM10 and PM2.5 concentrations were only observed among the individuals whom less frequently exercised. A statistically significant interaction effect was found between air pollution and exercise in training clothes for first-incident IHD but not for recurrence of IHD/stroke.Conclusions: The results in this thesis strengthen the public health message that physical activity is beneficial for cardiovascular health, even in areas with air pollution. Therefore, public health and transport policies should be designed to improve population health through promotion of active transport and mitigation of air pollution.
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| 2. |
- Aldrin, Viktor, 1980-
(författare)
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Prayer in Peasant Communities : Ideals and Practices of Prayer in the Late Medieval Ecclesiastical Province of Uppsala, Sweden
- 2010
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- The aim of this study has been to identify, explain and delineate praying among peasant communities in the ecclesiastical province of Uppsala, Sweden. Four aspects have been examined through the perspectives of ideals and practices, namely the standards of prayer, devotional prayer, prayer in times of need and prayer cultures. The standards of prayer considered the physical and mental behaviour of the praying peasant woman or man. The most ordinary way to act during prayer was to stand with hands together, palm against palm, and to pray in the vernacular often using mental themes to enhance the devotion. Devotional prayers were foremost the three ‘standard’ prayers Paternoster, Hail Mary and Apostolic Creed, and could be used separately or combined. Prayer in times of need was possibly considered a matter of praying to saints, something that cannot be proven to have been either practiced or recommended on other, ordinary occasions where God and the Virgin Mary were considered the proper recipients of prayer. A few authentic prayers exist that were possibly said by peasant women and men in connection with miracles and these show the ability to construct elaborate prayers and to propose businesslike agreements with saints. These three prayers were required knowledge for a peasant woman or man and were put to the test in order to become a godparent, and were therefore made available in the vernacular by the parish priests. Ways to maintain the prayer cultures were through mnemonic techniques, and indulgences stipulating and confirming prayers used or to be used in connection with certain churches, days and places within the churches. Name saints could also be used, since the person and the name saint were considered to have a special bond. Prayer could also be used as protection for the living; since a prayer was considered to generate either merits or favours from a celestial patron to his or her client. The prayer life of those belonging to peasant communities was both elaborate and full of nuances.
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| 3. |
- Hertz, Erik, 1956-
(författare)
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Methodologies for Approximation of Unary Functions and Their Implementation in Hardware
- 2016
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Applications in computer graphics, digital signal processing, communication systems, robotics, astrophysics, fluid physics and many other areas have evolved to become very computation intensive. Algorithms are becoming increasingly complex and require higher accuracy in the computations. In addition, software solutions for these applications are in many cases not sufficient in terms of performance. A hardware implementation is therefore needed. A recurring bottleneck in the algorithms is the performance of the approximations of unary functions, such as trigonometric functions, logarithms and the square root, as well as binary functions such as division. The challenge is therefore to develop a methodology for the implementation of approximations of unary functions in hardware that can cope with the growing requirements. The methodology is required to result in fast execution time, low complexity basic operations that are simple to implement in hardware, and – sincemany applications are battery powered – low power consumption. To ensure appropriate performance of the entire computation in which the approximation is a part, the characteristics and distribution of the approximation error are also things that must be possible to manage. The new approximation methodologies presented in this thesis are of the type that aims to reduce the sizes of the look-up tables by the use of auxiliary functions. They are founded on a synthesis of parabolic functions by multiplication – instead of addition, which is the most common. Three approximation methodologies have been developed; the two last being further developments of the first. For some functions, such as roots, inverse and inverse roots, a straightforward solution with an approximation is not manageable. Since these functions are frequent in many computation intensive algorithms, it is necessary to find very efficient implementations of these functions. New methods for this are also presented in this thesis. They are all founded on working in a floating-point format, and, for the roots functions, a change of number base is also used. The transformations not only enable simpler solutions but also increased accuracy, since the approximation algorithm is performed on a mantissa of limited range. Tools for error analysis have been developed as well. The characteristics and distribution of the approximation error in the new methodologies are presented and compared with existing state-of-the-art methods such as CORDIC. The verification and evaluation of the solutions have to a large extent been made as comparative ASIC implementations with other approximation methods, separately or embedded in algorithms. As an example, an implementation of the logarithm made using the third methodology developed, Harmonized Parabolic Synthesis (HPS), is compared with an implementation using the CORDIC algorithm. Both implementations are designed to provide 15-bit resolution. The design implemented using HPS performs 12 times better than the CORDIC implementation in terms of throughput. In terms of energy consumption, the new methodology consumes 96% less. The chip area is 60% smaller than for the CORDIC algorithm. In summary, the new approximation methodologies presented are found to well meet the demanding requirements that exist in this area.
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| 4. |
- Sundström, Johan, Professor, 1971-, et al.
(författare)
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Risk factors for subarachnoid haemorrhage : a nationwide cohort of 950 000 adults
- 2019
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Ingår i: International Journal of Epidemiology. - : Oxford University Press. - 0300-5771 .- 1464-3685. ; 48:6, s. 2018-2025
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: Subarachnoid haemorrhage (SAH) is a devastating disease, with high mortality rate and substantial disability among survivors. Its causes are poorly understood. We aimed to investigate risk factors for SAH using a novel nationwide cohort consortium.METHODS: We obtained individual participant data of 949 683 persons (330 334 women) between 25 and 90 years old, with no history of SAH at baseline, from 21 population-based cohorts. Outcomes were obtained from the Swedish Patient and Causes of Death Registries.RESULTS: During 13 704 959 person-years of follow-up, 2659 cases of first-ever fatal or non-fatal SAH occurred, with an age-standardized incidence rate of 9.0 [95% confidence interval (CI) (7.4-10.6)/100 000 person-years] in men and 13.8 [(11.4-16.2)/100 000 person-years] in women. The incidence rate increased exponentially with higher age. In multivariable-adjusted Poisson models, marked sex interactions for current smoking and body mass index (BMI) were observed. Current smoking conferred a rate ratio (RR) of 2.24 (95% CI 1.95-2.57) in women and 1.62 (1.47-1.79) in men. One standard deviation higher BMI was associated with an RR of 0.86 (0.81-0.92) in women and 1.02 (0.96-1.08) in men. Higher blood pressure and lower education level were also associated with higher risk of SAH.CONCLUSIONS: The risk of SAH is 45% higher in women than in men, with substantial sex differences in risk factor strengths. In particular, a markedly stronger adverse effect of smoking in women may motivate targeted public health initiatives.
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| 5. |
- Elf, Kristin, 1976-
(författare)
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Secondary Insults in Neurointensive Care of Patients with Traumatic Brain Injury
- 2005
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Traumatic brain injury (TBI) is a major cause of death and disability. Intracranial secondary insults (e.g. intracranial haematoma, brain oedema) and systemic secondary insults (e.g. hypotension, hypoxaemia, hyperthermia) lead to secondary brain injury and affect outcome adversely. In order to minimise secondary insults and to improve outcome in TBI-patients, a secondary insult program and standardised neurointensive care (NIC) was implemented. The aim of this thesis was to describe patient outcome and to explore the occurrence and prognostic value of secondary insults after the implementation.Favourable outcome was achieved in 79% and 6% died of the 154 adult TBI patients treated in the NIC unit 1996-97. In an earlier patient series from the department, 48% made a favourable outcome and 31% died. Hence, the outcome seems to have improved when NIC was standardised and dedicated to avoiding secondary insults. Secondary insults counted manually from hourly recordings on surveillance charts did not hold any independent prognostic information. When utilising a computerised system, which enables minute-by-minute data collection, the proportion of monitoring time with systolic blood pressure > 160 mm Hg decreased the odds of favourable outcome independent of admission variables (odds ratio 0.66). Hyperthermia was related to unfavourable outcome. Hypertension was correlated to hyperthermia and may be a part of a hyperdynamic state aggravating brain oedema. Increased proportion of monitoring time with cerebral perfusion pressure (CPP) < 60 mm Hg increased the odds of favourable outcome (odds ratio 1.59) in patients treated according to an intracranial pressure (ICP)-oriented protocol (Uppsala). In patients given a CPP-oriented treatment (Edinburgh), CPP <60 mm Hg was coupled to an unfavourable outcome. It was shown that pressure passive patients seem to benefit from an ICP-oriented protocol and pressure active patients from a CPP-oriented protocol. The overall outcome would improve if patients were given a treatment fit for their condition.
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| 6. |
- Hultdin, Johan, 1964-
(författare)
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Homocysteine in cardiovascular disease with special reference to longitudinal changes
- 2005
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Abnormalities in homocysteine metabolism have been suggested as risk factors for stroke and myocardial infarction. In retrospective studies, elevated levels of total plasma homocysteine (tHcy) and/or methylenetetrahydrofolate reductase (MTHFR) 677C>T polymorphism have indicated an increase in risk. However, the fewer prospective studies have not been as conclusive. To further explore this, tHcy was studied in four prospective settings. The first was a prospective nested case-referent cohort within the Västerbotten Intervention Program (VIP) and WHO MONICA project on 312 ischemic and 60 haemorrhagic first-ever strokes. The aim was to study tHcy and its main genetic determinant MTHFR. Risk for haemorrhagic stroke increased exponentially through tHcy quartiles, independent of hypertension and BMI, and increased for MTHFR 677 CT and TT. MTHFR 1298A>C appeared to be protective. In multivariate models, after adjustment for tHcy, BMI and hypertension, both tHcy and MTHFR remained as independent predictors for hemorrhagic stroke. Neither tHcy, nor the two MTHFR polymorphisms were significant predictors for ischemic strokes. The second was a prospective long-term follow-up study within the VIP and MONICA cohorts to determine whether a first-ever myocardial infarction (AMI) causes increased levels of tHcy. Fifty cases developing AMI after the first screening participated in a second screening (mean follow-up 8.5 years) with 56 matched referents. Increase in tHcy did not differ between cases and referents. tHcy was related to AMI at follow-up, but not at baseline and no longer significant after adjusting for creatinine and albumin. The third was a method study to determine if cystatin C, creatinine, albumin and other lipoprotein risk markers of cardiovascular disease could be analysed in Stabilyte™ plasma stored at -80°C. It was found to be suitable for all analyses tested and using this tube would simplify sampling for epidemiological studies. The fourth study was a prospective longitudinal long-term study of 735 subjects (340 men and 395 women, age 25-64 at first screening), participating in two MONICA screenings nine years apart, who donated blood in Stabilyte™ tubes to study change over time in tHcy and its determinants. We confirmed the age dependency in a cross sectional setting. In contrast, if followed longitudinally over time, no change in tHcy or in the prevalence of hyperhomocysteinemia was found. Cystatin C and creatinine increased, and albumin decreased. In multivariate models baseline levels of albumin, creatinine, cystatin C, and to some extent hs-CRP, were predictors of tHcy at follow-up but gender differences were seen. Age was not a major determinant of change in tHcy over nine years. In conclusion, tHcy and MTHFR are risk factors for first-ever haemorrhagic, but not ischemic stroke in a prospective setting. A first myocardial infarction does not cause an increase in tHcy. No long-term changes were seen in tHcy over a nine-year period in neither men, nor in women.
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| 7. |
- Kriit, Hedi Katre, et al.
(författare)
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A health economic assessment of air pollution effects under climate neutral vehicle fleet scenarios in Stockholm, Sweden
- 2021
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Ingår i: Journal of Transport and Health. - : Elsevier BV. - 2214-1405. ; 22
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Tidskriftsartikel (refereegranskat)abstract
- Introduction: Electric vehicles (EVs) are heavily promoted as beneficial for climate and health. In most studies, it is assumed that EVs contribution to urban air pollution is zero due to no tailpipe emissions, ignoring the contribution of non-exhaust particles (brake, tire and road wear), which are unregulated in EU. This study of Stockholm, Sweden, aims to 1) assess how a future vehicle fleet impacts concentrations of particles of size less than 2.5 μm (PM2.5) and evaluate the expected health outcomes economically and 2) compare this with CO2 savings. Methods: Source specific dispersion models of exhaust and non-exhaust PM2.5 was used to estimate the population weighted concentrations. Thereafter exposure differences within a business as usual (BAU2035) and a fossil free fuel (FFF2035) scenario were used to assess expected health and economic impacts. The assessment considered both exhaust and non-exhaust emissions, considering the vehicle weight and the proportion of vehicles using studded winter tires. Health economic costs were retrieved from the literature and societal willingness to pay was used to value quality-adjusted life-years lost due to morbidity and mortality. Results: The mean population weighted exhaust PM2.5 concentration decreased 0.012 μg/m3 (39%) in FFF2035 as compared to BAU2035. Assuming 50% higher road and tire wear PM2.5 emission because of higher weight among EVs and 30% less brake wear emissions, the estimated decrease in wear particle exposures were 0.152 (22%) and 0.014 μg/m3 (1.9%) for 0 and 30% use on studded winter tires, respectively. The resulting health economic costs were estimated to €217M and €32M, respectively. An increase by 0.079 μg/m3 (11%) was however estimated for 50% use of studded winter tires, corresponding to an €89M increase in health costs. Conclusion: Considering both exhaust and wear generated particles, it is not straight forward that an increase of EVs will decrease the negative health impacts.
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| 8. |
- Kriit, Hedi Katre, et al.
(författare)
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Increase in sick leave episodes from short-term fine particulate matter exposure : a case-crossover study in Stockholm, Sweden
- 2024
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Ingår i: Environmental Research. - : Elsevier. - 0013-9351 .- 1096-0953. ; 244
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Tidskriftsartikel (refereegranskat)abstract
- Air pollution's short-term effects on a wide range of health outcomes have been studied extensively, primarily focused on vulnerable groups (e.g., children and the elderly). However, the air pollution effects on the adult working population through sick leave have received little attention. This study aims to 1) estimate the associations between particulate matter ≤2.5 μm3 (PM2.5) and sick leave episodes and 2) calculate the attributable number of sick leave days and the consequential productivity loss in the City of Stockholm, Sweden. Individual level daily sick leave data was obtained from Statistics Sweden for the years 2011–2019. Daily average concentrations of PM2.5 were obtained from the main urban background monitoring station in Stockholm. A case-crossover study design was applied to estimate the association between short-term PM2.5 and onset of sick leave episodes. Conditional logistic regression was used to estimate the relative increase in odds of onset per 10 μg/m3 of PM2.5, adjusting for temperature, season, and pollen. A human capital method was applied to estimate the PM2.5 attributable productivity loss. In total, 1.5 million (M) individual sick leave occurrences were studied. The measured daily mean PM2.5 concentration was 4.2 μg/m3 (IQR 3.7 μg/m3). The odds of a sick leave episode was estimated to increase by 8.5% (95% CI: 7.8–9.3) per 10 μg/m3 average exposure 2–4 days before. Sub-group analysis showed that private sector and individuals 15–24 years old had a lower increase in odds of sick leave episodes in relation to PM2.5 exposure. In Stockholm, 4% of the sick leave episodes were attributable to PM2.5 exposure, corresponding to €17 M per year in productivity loss. Our study suggests a positive association between PM2.5 and sick leave episodes in a low exposure area.
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| 9. |
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| 10. |
- Kriit, Hedi Katre, et al.
(författare)
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Using Distributed Lag Non-Linear Models to Estimate Exposure Lag-Response Associations between Long-Term Air Pollution Exposure and Incidence of Cardiovascular Disease
- 2022
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Ingår i: International Journal of Environmental Research and Public Health. - : MDPI AG. - 1661-7827 .- 1660-4601. ; 19:5
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Tidskriftsartikel (refereegranskat)abstract
- Long-term air pollution exposure increases the risk for cardiovascular disease, but little is known about the temporal relationships between exposure and health outcomes. This study aims to estimate the exposure-lag response between air pollution exposure and risk for ischemic heart disease (IHD) and stroke incidence by applying distributed lag non-linear models (DLNMs). Annual mean concentrations of particles with aerodynamic diameter less than 2.5 µm (PM2.5 ) and black carbon (BC) were estimated for participants in five Swedish cohorts using dispersion models. Simultaneous estimates of exposure lags 1–10 years using DLNMs were compared with separate year specific (single lag) estimates and estimates for lag 1–5-and 6–10-years using moving average exposure. The DLNM estimated no exposure lag-response between PM2.5 total, BC, and IHD. However, for PM2.5 from local sources, a 20% risk increase per 1 µg/m3 for 1-year lag was estimated. A risk increase for stroke was suggested in relation to lags 2–4-year PM2.5 and BC, and also lags 8–9-years BC. No associations were shown in single lag models. Increased risk estimates for stroke in relation to lag 1–5-and 6–10-years BC moving averages were observed. Estimates generally supported a greater contribution to increased risk from exposure windows closer in time to incident IHD and incident stroke. © 2022 by the authors. Licensee MDPI, Basel, Switzerland.
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