| 1. |
- Melchior, Maria, et al.
(författare)
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Using sickness absence records to predict future depression in a working population : prospective findings from the GAZEL cohort.
- 2009
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Ingår i: American journal of public health. - 1541-0048. ; 99:8, s. 1417-22
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Tidskriftsartikel (refereegranskat)abstract
- OBJECTIVES: We tested the hypothesis that sickness absence from work predicts workers' risk of later depression. METHODS: Study participants (n = 7391) belonged to the French GAZEL cohort of employees of the national gas and electricity company. Sickness absence data (1996-1999) were obtained from company records. Participants' depression in 1996 and 1999 was assessed with the Center for Epidemiologic Studies-Depression (CES-D) scale. The analyses were controlled for baseline age, gender, marital status, occupational grade, tobacco smoking status, alcohol consumption, subthreshold depressive symptoms, and work stress. RESULTS: Among workers who were free of depression in 1996, 13% had depression in 1999. Compared with workers with no sickness absence during the study period, those with sickness absence were more likely to be depressed at follow-up (for 1 period of sickness absence, fully adjusted odds ratio [OR] = 1.53, 95% confidence interval [CI] = 1.28, 1.82; for 2 or more periods, fully adjusted OR = 1.95, 95% CI = 1.61, 2.36). Future depression was predicted both by psychiatric and nonpsychiatric sickness absence (fully adjusted OR = 3.79 [95% CI = 2.81, 5.10] and 1.41 [95% CI = 1.21, 1.65], respectively). CONCLUSIONS: Sickness absence records may help identify workers vulnerable to future depression.
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| 4. |
- Westerlund, Camilla, et al.
(författare)
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Dynamics of urban snowmelt and runoff during different climatic conditions
- 2006
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- Within the European Union, and maybe especially in Scandinavia, access to clean water is taken for granted without a second thought. However, it is not often realized that many of the human activities put a great burden on water quality and quantity. All polluted water, whether polluted by households, industry, agriculture, or traffic returns back, in some way, to the environment and may cause damage to human health or the environment. The increasing demand for cleaner rivers and lakes, groundwater and coastal beaches was the driving force for the EU Water Framework Directive which overall aim is to obtain, and keep a "good status" for water within EU. The protection should include all waters, surface waters and groundwater and should be achieved before year 2015. With these increasing demands upon water quality, further research is required in terms of the quantity and quality of road runoff.Further research is required particularly in areas with a cold climate since special conditions occur - storage of precipitation and pollutants in snowpacks during extended time periods, processes in the snowpack influencing the availability of pollutants, and dissimilar surface and transport network due to snow and ice. As a result, the runoff quantity and quality will differ compared to snow and-ice free climates (Marsalek, 2003). Also, it is of importance to realise that areas with cold climate can be subdivided into smaller areas with different climatic zones. For example, when looked upon Sweden, the winter could be divided into two different types. One type of winter climate, which is found in the south of Sweden, has a temperature often fluctuating around zero. Snowfall is received occasionally when the temperature is below zero, however, the snow is melting instantaneously or shortly after the snowfall. The other type of winter climate is what could be found in the north of Sweden, having long periods with temperatures below zero degrees. During this time there is an accumulation of snow and pollutants until the spring time when the temperature is fluctuating around zero and the snowmelt begins. This melt period resemble the winter climate found in the south of Sweden and is critical when it comes to risks connected to both quality and quantity. The highest concentrations of pollutants and the highest flows are found during snowmelt and rain-on-snow events respectively. There are many differences between the two different winter climates. The usage of salt on roads as a slipperiness control measure is more common in the southern parts of Sweden. Since the temperature often is around zero during winter time, the build-up of ice layers on roads are common. In the north of Sweden, it is often too cold to have a build-up of ice and the de-icers do not work at these low temperatures. Another difference is that the build up of pollutants is more significant for the winter climates with long, cold periods since the freezing-thawing cycles are not as frequent. When this accumulated snow is starting to melt, we get large quantities of water and also high concentrations of pollutants. However, to decrease the impacts from road runoff in cold regions, it is critical to not only understand the dynamics of pollutants, but also to use this knowledge in models to predict and prevent environmental damage. In this article the winter season will be subdivided into three different climategroups, one group where the temperature stays below zero during the whole winter period, the second group where the temperature is fluctuating between plus and minus five degrees, and the third group where the temperature is above zero degrees during the whole winter period. Processes and influencing factors will be investigated for all three groups in terms of dynamics of snowmelt and runoff and the quality of stormwater during the different conditions, see Figure 1. Also, a selection of commonly used models of today will be investigated and compared to see what equations are describing these physical and chemical processes. Figure1. Factors affecting the stormwater quantity and quality. Marsalek, J. (2003). Road salts in urban stormwater: an emerging issue in stormwater management in cold climate. Water, Science and Technology, vol. 48, No.9, pp 61-70.
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| 5. |
- Westerlund, Camilla, et al.
(författare)
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Modelling of snowmelt and rainfall runoff : dynamics of road runoff and suspended solid transport
- 2005
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Ingår i: Urban drainage 2005. - London : IWA Publishing. - 1843395746
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Konferensbidrag (refereegranskat)abstract
- In this paper, a simple model concept is presented to describe the dynamics of road runoff and suspended-solid transport from a small urban catchment in northern Sweden. The study period stretches from March 28 to May 28, 2000, including both snowmelt and rainfall. A modified degree-day method is used to describe the snowmelt and the transport of suspended solids is described by a linear build-up function and a wash-off model. The model was verified through measurements taken from March 22 to May 22, 2001. The results from the simulations showed that the simple model concept was capable of describing the dynamics of road runoff and suspended solids rather well, based on the continuous course of events for the whole modelling period. However, if the model was used for simulating a snowmelt period, or single events during snowmelt, the model approach would be too simple.
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| 6. |
- Westerlund, Camilla, et al.
(författare)
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Modelling sediment transport during snowmelt- and rainfall-induced road runoff
- 2008
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Ingår i: Nordic Hydrology. - : IWA Publishing. - 0029-1277 .- 1996-9694. ; 39:2, s. 113-122
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Tidskriftsartikel (refereegranskat)abstract
- In this paper, a simple conceptual model is presented to describe the dynamics of total suspended solid (TSS) transport during snowmelt- and rainfall-induced road runoff from a small urban runoff plot in northern Sweden. The study period (28 March to 28 May 2000) included both snowmelt and rainfall. A temperature-index method is used to describe snowmelt and the accumulation and transport of TSS is described by a linear build-up function and a wash-off model. The model was verified through measurements taken from 22 March to 22 May 2001. The simulation results showed that the simple model concept was capable of describing the dynamics of road runoff and TSS well, based on the continuous course of events for the whole modelling period. However, if the model was used for simulating a snowmelt period, or single events during snowmelt, the model approach would be too simple.
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| 7. |
- Westerlund, Camilla, et al.
(författare)
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Particles and associated metals in road runoff during snowmelt and rainfall
- 2006
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Ingår i: Science of the Total Environment. - : Elsevier BV. - 0048-9697 .- 1879-1026. ; 362:1-3, s. 143-156
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Tidskriftsartikel (refereegranskat)abstract
- This study analysed road runoff in northern Sweden with respect to the concentrations of and the loads of particles in different size fractions (4-6, 6-9, 9-15, 15-25, 25-40, and 40-120 μm) between a snowmelt period and a rainfall period, as well as during events within each period. There are also comparisons of the transport of different particle sizes between the two periods and during events within the periods and discussions on how different metals are associated with the varying particle sizes. The results showed, on average, eight times higher concentrations and five times higher loads of particles during the snowmelt period compared to the rain period for all particle size intervals. Using a t-test with 14 degrees of freedom, at a 90% and 95% confidence level, the mean- and the event mean concentrations of all particle size intervals were higher during the melt period compared to the rain period. Also, the particle concentrations for both periods decrease as the particle size increases. During the snowmelt and rainfall period, important factors influencing the concentrations and loads were the availability of material, the intensity of the lateral flow for the transport of the particles, and, additionally, for the rain period, the length of dry weather in between events. During the melt period, investigated particle sizes and TSS were highly correlated with total concentrations of Cd, Cu, Ni, Pb, and Zn. During the rain period, the correlations between total metal concentrations and the different particle sizes were not as significant.
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| 8. |
- Westerlund, Camilla, et al.
(författare)
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Stormwater in cold climates
- 2007
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Ingår i: DayWater. - London : IWA Publishing. - 9781843391609 ; , s. 231-246
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Bokkapitel (övrigt vetenskapligt/konstnärligt)
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| 9. |
- Westerlund, Camilla, et al.
(författare)
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Transport of total suspended solids during snowmelt : influence by road salt, temperature and surface slope
- 2008
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Ingår i: Water, Air and Soil Pollution. - : Springer Science and Business Media LLC. - 0049-6979 .- 1573-2932. ; 192:1-4, s. 3-10
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Tidskriftsartikel (refereegranskat)abstract
- In the beginning of March 2006, polluted snow from a roadside in Luleå, in the north of Sweden, with a traffic intensity of approximately 7,400 vehicles per day, was collected. The snow was homogenously mixed and divided into samples of 30 litres. The initial volumes and densities of the snow samples were measured and calculated. The snow samples were melted in climate rooms, with four different experimental configurations, to investigate the influence of road salt, temperature, and surface slope upon the transport of total suspended solids (TSS) (three replicates for each experimental configuration). The total volume of snowmelt runoff was collected and analysed for pH, conductivity, and concentrations of TSS and chlorides. The results showed that measured concentrations, calculated mass loads, and performed statistical t-tests of TSS for the snowmelt of the four different configurations implied that the transported mass load of TSS was higher with the addition of road salt and at higher ambient temperatures. However, the results showed a lower mass load of transported TSS for the lower slope.
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| 10. |
- Westerlund, Hugo, et al.
(författare)
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Self-rated health before and after retirement in France (GAZEL) : a cohort study.
- 2009
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Ingår i: Lancet. - 1474-547X. ; 374:9705, s. 1889-96
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: Governments need to increase the proportion of the population in work in most developed countries because of ageing populations. We investigated longitudinally how self-perceived health is affected by work and retirement in older workers. METHODS: We examined trajectories of self-rated health in 14 714 employees (11 581 [79%] men) from the French national gas and electricity company, the GAZEL cohort, for up to 7 years before and 7 years after retirement, with yearly measurements from 1989 to 2007. We analysed data by use of repeated-measures logistic regression with generalised estimating equations. FINDINGS: Overall, suboptimum health increased with age. However, between the year before retirement and the year after, the estimated prevalence of suboptimum health fell from 19.2% (95% CI 18.5-19.9) to 14.3% (13.7-14.9), corresponding to a gain in health of 8-10 years. We noted this retirement-related improvement in men (odds ratio 0.68, 95% CI 0.64-0.73) and women (0.74, 0.67-0.83), and across occupational grades (low 0.72, 0.63-0.82; high 0.70, 0.63-0.77), and it was maintained throughout the 7 years after retirement. A poor work environment and health complaints before retirement were associated with a steeper yearly increase in the prevalence of suboptimum health while still in work, and a greater retirement-related improvement; however, people with a combination of high occupational grade, low demands, and high satisfaction at work showed no such retirement-related improvement. INTERPRETATION: These findings suggest that the burden of ill-health, in terms of perceived health problems, is substantially relieved by retirement for all groups of workers apart from those with ideal working conditions, and that working life for older workers needs to be redesigned to achieve higher labour-market participation. FUNDING: Swedish Council for Working Life and Social Research, Academy of Finland, INSERM (France), BUPA Foundation (UK), European Science Foundation, and Economic and Social Research Council (UK).
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