The Topographic Wetness Index (TWI) is a commonly used proxy for soil moisture. The predictive capability of TWI is influenced by the flow‐routing algorithm and the resolution of the Digital ...Elevation Model (DEM) that TWI is derived from. Here, we examine the predictive capability of TWI using 11 flow‐routing algorithms at DEM resolutions 1–30 m. We analyze the relationship between TWI and field‐quantified soil moisture using statistical modeling methods and 5,200 study plots with over 46 000 soil moisture measurements. In addition, we test the sensitivity of the flow‐routing algorithms against vertical height errors in DEM at different resolutions. The results reveal that the overall predictive capability of TWI was modest. The highest r2 (23.7%) was reached using a multiple‐flow‐direction algorithm at 2 m resolution. In addition, the test of sensitivity against height errors revealed that the multiple‐flow‐direction algorithms were also more robust against DEM errors than single‐flow‐direction algorithms. The results provide field‐evidence indicating that at its best TWI is a modest proxy for soil moisture and its predictive capability is influenced by the flow‐routing algorithm and DEM resolution. Thus, we encourage careful evaluation of algorithms and resolutions when using TWI as a proxy for soil moisture.
Plain Language Summary
Soil moisture is a microclimate variable that can vary from one meter to another. The spatial variation of soil moisture is related to many patterns in nature. Often, soil moisture data is based on single point measurements, which are hard to extend over large areas. Therefore, it is useful to have proxies of soil moisture that can be used instead of field data. We investigated how well a commonly used moisture proxy, the Topographic Wetness Index, is related to field measurements of soil moisture. Our results revealed that at its best, the predictive capability of the proxy was modest. We found that algorithm and resolution of the proxy influenced how well the proxy related to soil moisture. This is important because a poor choice of algorithm and resolution can underestimate the role of soil moisture for instance in ecosystem models. Therefore, we encourage researchers to carefully consider which is the most suitable algorithm and resolution for their study.
Key Points
The predictive capability of Topographic Wetness Index as a proxy for soil moisture varied from very low to modest
The predictive capability was dictated by the flow‐routing algorithm and the resolution of the Digital Elevation Model (DEM)
Multiple‐flow‐direction algorithms had higher explanatory power and more robustness against DEM errors than single‐flow‐direction algorithms
To study the association between overweight and lumbar disc degeneration.
Population-based 4-y follow-up magnetic resonance imaging (MRI) study.
The subjects were 129 working middle-aged men selected ...to the baseline magnetic resonance imaging (MRI) study from a cohort of 1832 men representing three occupations: machine drivers, construction carpenters, and office workers. The selection was based on the paticipants' age (40-45 y) and place of residence. MR images of the lumbar spines were obtained at baseline and at 4-y follow-up.
Signal intensity of the nucleus pulposus of the discs L2/L3-L4/L5 was visually assessed by two readers using the adjacent cerebrospinal fluid as an intensity reference. The weight (at age 25 and 40-45 y) and height of the subjects, history of car driving, smoking, and back injuries were assessed by questionnaire.
Multiple regression analyses allowing for occupation, history of car driving, smoking, and back injuries showed that persistent overweight (body mass index (BMI) > or =25 kg/m(2) at both ages) associated strongly with an increased risk of the number of lumbar discs with decreased signal intensity of nucleus pulposus at follow-up, adjusted odds ratio (OR) being 4.3 (95% confidence intervals (95% CIs) 1.3-14.3). Overweight at young age (risk ratio (RR) 3.8; 95% CI 1.4-10.4) was a stronger predictor of an increase in the number of degenerated discs during follow-up than overweight in middle age (RR 1.3; 95% CI 0.7-2.7).
The study provides evidence that the BMI above 25 kg/m(2) increases the risk of lumbar disc degeneration. Overweight at young age seems to be particularly detrimental.
Based on a hypothesis that interleukin 1 (IL-1) activity is associated with low back pain (LBP), we investigated relationships between previously described functional IL-1 gene polymorphisms and LBP. ...The subjects were a subgroup of a Finnish study cohort. The IL-1alpha(C(889)-T), IL-1beta(C(3954)-T) and IL-1 receptor antagonist (IL-1RN)(G(1812)-A, G(1887)-C and T(11100)-C) polymorphisms were genotyped in 131 middle-aged men from three occupational groups (machine drivers, carpenters and office workers). A questionnaire inquired about individual and lifestyle characteristics and the occurrence of LBP, the number of days with pain and days with limitation of daily activities because of pain, and pain intensity, during the past 12 months. Lumbar disc degeneration was determined with magnetic resonance imaging. Carriers of the IL-1RNA(1812) allele had an increased risk of LBP (OR 2.5, 95% CI 1.0-6.0) and carriers of this allele in combination with the IL-1alphaT(889) or IL-1betaT(3954) allele had a higher risk of and more days with LBP than non-carriers. Pain intensity was associated with the simultaneous carriage of the IL-1alphaT(889) and IL-1RNA(1812) alleles (OR 3.7, 95% CI 1.2-11.9). Multiple regression analyses allowing for occupation and disc degeneration showed that carriage of the IL-1RNA(1812) allele was associated with the occurrence of pain, the number of days with pain and days with limitations of daily activities. Carriage of the IL-1betaT(3954) allele was associated with the number of days with pain. The results suggest a possible contribution of the IL-1 gene locus polymorphisms to the pathogenesis of LBP. The possibility of chance findings cannot be excluded due to the small sample size.
Objectives. To investigate the effect of mechanical stress on finger osteoarthritis (OA) by comparing women from two occupations with different hand load but the same socio-economic grade, and to ...investigate whether hand load may affect the pattern of joint involvement in OA. Methods. Radiographs of both hands of 295 dentists and 248 teachers were examined. Each interphalangeal (distal, proximal and thumb interphalangeal) and the metacarpophalangeal joints were graded (0 = no OA, 4 = severe OA) separately by using reference images. The co-involvement of different hand joints was analysed by logistic regression. Results. The distal interphalangeal joints were the most frequently involved joints. The non-dominant hand was more frequently affected by OA of grade 2 or more than the dominant hand. The prevalence of OA of grade 2 or more in any finger joint and also in any distal interphalangeal joint was higher among the teachers compared with the dentists (59 vs 48%, P = 0.020 and 58 vs 47%, P<0.010 respectively). Finger OA showed more clustering in the ring and little fingers and more row clustering and symmetry in the teachers than in the dentists age-adjusted odds ratio (OR) = 1.57, 95% confidence interval (CI) 1.10–2.23, OR = 1.84, 95% CI 1.28–2.64, and OR = 1.98, 95% CI 1.38–2.86 respectively. The OR of more severe OA (grade 3 or more) in the right-hand thumb and the index and middle fingers was significantly elevated among the dentists compared with the teachers (OR 2.61, 95% CI 1.03–6.59). Conclusion. Our findings indicate that finger OA in middle-aged women is highly prevalent and often polyarticular. Hand use may have a protective effect on finger joint OA, whereas continuing joint overload may lead to joint impairment.
Cross-sectional magnetic resonance imaging (MRI) study.
To study the relation of low back pain (LBP) to disc degeneration in the lumbar spine.
Controversy still prevails about the relationship ...between disc degeneration and LBP. Classification of disc degeneration and symptoms varies, hampering comparison of study results.
Subjects comprised 164 men aged 40-45 years-53 machine drivers, 51 construction carpenters, and 60 office workers. The data of different types of LBP, individual characteristics, and lifestyle factors were obtained from a questionnaire and a structured interview. Degeneration of discs L2/L3-L5/S1 (dark nucleus pulposus and posterior and anterior bulge) was assessed with MRI.
An increased risk of LBP (including all types) was found in relation to all signs of disc degeneration. An increased risk of sciatic pain was found in relation to posterior bulges, but local LBP was not related to disc degeneration. The risks of LBP and sciatic pain were strongly affected by occupation.
Low back pain is associated with signs of disc degeneration and sciatic pain with posterior disc bulges. Low back pain is strongly associated with occupation.
Objectives:To examine the efficacy of a participatory ergonomics intervention in preventing musculoskeletal disorders among kitchen workers. Participatory ergonomics is commonly recommended to reduce ...musculoskeletal disorders, but evidence for its effectiveness is sparse.Methods:A cluster randomised controlled trial among the 504 workers of 119 kitchens in Finland was conducted during 2002–2005. Kitchens were randomised to an intervention (n = 59) and control (n = 60) group. The duration of the intervention that guided the workers to identify strenuous work tasks and to seek solutions for decreasing physical and mental workload, was 11 to 14 months. In total, 402 ergonomic changes were implemented. The main outcome measures were the occurrence of and trouble caused by musculoskeletal pain in seven anatomical sites, local fatigue after work, and sick leave due to musculoskeletal disorders. Individual level data were collected by a questionnaire at baseline and every 3 months during the intervention and 1-year follow-up period. All response rates exceeded 92%.Results:No systematic differences in any outcome variable were found between the intervention and control groups during the intervention or during the 1-year follow-up.Conclusions:The intervention did not reduce perceived physical work load and no evidence was found for the efficacy of the intervention in preventing musculoskeletal disorders among kitchen workers. It may be that a more comprehensive redesign of work organisation and processes is needed, taking more account of workers’ physical and mental resources.
OBJECTIVES To evaluate the effects of work related and individual factors as well as physical activity and sports on the incidence and persistence of shoulder pain among forestry workers. METHODS ...Workers in a large Finnish forestry company replied to a questionnaire (a modified version of the Nordic questionnaire) on musculoskeletal pain and its possible risk factors for 4 consecutive years 1992–5. This 1 year follow up study covers the time 1994–5. Year 1994 was chosen as baseline because in that year the questionnaire contained for the first time more detailed questions about different sports. The response rate in 1995 was 90%. The effects of the predictors on 1 year incidence and persistence of shoulder pain were studied with multivariate logistic regression modelling. RESULTS At baseline, 2094 subjects had been free of shoulder pain during the preceding 12 months. After 1 year, 14% (n=285) reported having mild or severe shoulder pain. Higher age, obesity, and mental stress as well as physically strenuous work and working with trunk forward flexed or with a hand above shoulder level increased the risk of incident shoulder pain. Of the different sports activities, dancing increased the risk of incident pain whereas jogging decreased the risk significantly. Of those 419 workers who had severe shoulder pain at baseline, 55% (n=230) still had severe pain 1 year later. Higher age, overload at work, and working with a hand above shoulder level increased the risk of persistent severe shoulder pain whereas cross country skiing and general sports activity decreased the risk. CONCLUSION Our results support the current view that shoulder pain is the result of many factors, including occupational and individual factors. In this longitudinal study, physical work with a heavy load, awkward work postures, mental stress, and obesity were the risk factors at which preventive measures could be aimed. As a new finding, physical exercise had more protective than impairing effects on the shoulders.
Objectives To evaluate the effects of work-related and individual factors as well as physical activity and sports on the incidence and persistence of knee pain among a working population.
Design ...Employees of a large Finnish forestry company replied to a questionnaire (a modified version of the Nordic Questionnaire) on musculoskeletal pain and its possible risk factors at the baseline of this study. A cohort of 2122 workers free of knee pain and another cohort of 333 workers with severe knee pain were followed up for one year. The effects of the risk factors on the incidence and persistence of knee pain were studied using multivariable logistic regression models.
Results A total of 214 (10%) workers developed knee pain during the follow-up. Significant predictors of incident knee pain in the multivariable model were higher age, overweight, smoking, and previous knee injuries. Also, working with the trunk forward flexed in kneeling or standing position and physically strenuous work were non-significant predictors of incident knee pain. Of those 333 workers with severe knee pain at baseline, 220 (66%) still reported severe knee pain after one year. Higher age and job dissatisfaction increased the risk of persistent symptoms. General physical exercise and different sports activities did not predict the incidence or persistence of knee pain.
Conclusions In this large prospective study, the risk factors for self-reported knee pain seemed to be highly similar to the risk factors for knee osteoarthritis (OA) reported in other papers. Age, previous knee injuries, overweight, and knee-straining work were those risk factors, which contributed to the incidence of knee pain. Psychosocial elements of work were more involved in the persistence of the symptoms in the knee. Copyright 2002 OsteoArthritis Research Society International. Published by Elsevier Science Ltd. All rights reserved.
Aims: To examine associations of leisure time physical activity and physical strenuousness of work with physical functioning 28 years later. Methods: A cohort (n = 902) of metal industry employees ...was studied for exercise and housework activity in 1973 and 1978, and for BMI, current smoking, strenuousness of work, grip strength, and chronic diseases in 1973. Of the 670 survivors in 2000, 529 (79%) responded to all studied items in a follow up questionnaire including the SF-36 Physical Functioning (PF) scale. Belonging to the lower quartile of the PF scale denoted poor functioning. Results: Vigorous exercise and housework activity were inversely associated with poor PF 28 years later in both white-collar and blue-collar workers. Engaging in activities of any intensity was similarly associated among the blue-collar workers. In a multiple logistic regression model including as independent variables age, sex, occupational class, the number of chronic diseases, vigorous leisure time physical activity, BMI, physical work strenuousness, and smoking (all measured at baseline), the risk of poor PF at follow up was decreased by vigorous leisure time physical activity and increased by high physical strenuousness of work, high BMI, and smoking. The effect of work strenuousness was mainly due to that among the blue-collar group. Allowing for baseline grip strength did not materially alter the results. Conclusion: Vigorous leisure time physical activity decreased the risk of poor physical functioning as perceived considerably later in life, while high work strenuousness, smoking, and overweight increased it. Among blue-collar workers a beneficial association was observed with all leisure time activity, including that of lower intensity.
OBJECTIVES To study the effects of work related and individual factors affecting radiating neck pain. METHODS A longitudinal study was carried out with repeated measurements. A total of 5180 Finnish ...forest industry workers replied to a questionnaire survey in 1992 (response rate 75%). Response rates to follow up questionnaires in 1993, 1994, and 1995 were 83%, 77%, and 90%, respectively. The outcome variable was the number of days with radiating neck pain during the preceding 12 months with three levels (<8, 8–30, >30 days). The generalised estimating equations method was used to fit a marginal model and a transition model was used in a predictive analysis. RESULTS Items showing associations with radiating neck pain in both analyses were sex, age, body mass index, smoking, duration of work with a hand above shoulder level, mental stress, and other musculoskeletal pains. In the transition model, radiating neck pain in a previous questionnaire was included in the model. Although it was a strong predictor, the variables already mentioned retained their significance. CONCLUSION Programmes targeted to reduce physical load at work, mental stress, being overweight, and smoking could potentially prevent radiating neck pain.
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