Owe Löfman

Landslide susceptibility mapping at Hoa Binh province (Vietnam) using an adaptive neuro-fuzzy inference system and GIS

The objective of this study is to investigate a potential application of the Adaptive Neuro-Fuzzy Inference System (ANFIS) and the Geographic Information System (GIS) as a relatively new approach for landslide susceptibility mapping in the Hoa Binh province of Vietnam. Firstly, a landslide inventory map with a total of 118 landslide locations was constructed from various sources. Then the landslide inventory was randomly split into a testing dataset 70% (82 landslide locations) for training the models and the remaining 30% (36 landslides locations) was used for validation purpose. Ten landslide conditioning factors such as slope, aspect, curvature, lithology, land use, soil type, rainfall, distance to roads, distance to rivers, and distance to faults were considered in the analysis. The hybrid learning algorithm and six different membership functions (Gaussmf, Gauss2mf, Gbellmf, Sigmf, Dsigmf, Psigmf) were applied to generate the landslide susceptibility maps. The validation dataset, which was not considered in the ANFIS modeling process, was used to validate the landslide susceptibility maps using the prediction rate method. The validation results showed that the area under the curve (AUC) for six ANFIS models vary from 0.739 to 0.848. It indicates that the prediction capability depends on the membership functions used in the ANFIS. The models with Sigmf (0.848) and Gaussmf (0.825) have shown the highest prediction capability. The results of this study show that landslide susceptibility mapping in the Hoa Binh province of Vietnam using the ANFIS approach is viable. As far as the performance of the ANFIS approach is concerned, the results appeared to be quite satisfactory, the zones determined on the map being zones of relative susceptibility.

Landslide Susceptibility Assessment in Vietnam Using Support Vector Machines, Decision Tree, and Naïve Bayes Models

The objective of this study is to investigate and compare the results of three data mining approaches, the support vector machines (SVM), decision tree (DT), and Naive Bayes (NB) models for spatial prediction of landslide hazards in the Hoa Binh province (Vietnam). First, a landslide inventory map showing the locations of 118 landslides was constructed from various sources. The landslide inventory was then randomly partitioned into 70% for training the models and 30% for the model validation. Second, ten landslide conditioning factors were selected (i.e., slope angle, slope aspect, relief amplitude, lithology, soil type, land use, distance to roads, distance to rivers, distance to faults, and rainfall). Using these factors, landslide susceptibility indexes were calculated using SVM, DT, and NB models. Finally, landslide locations that were not used in the training phase were used to validate and compare the landslide susceptibility maps. The validation results show that the models derived using SVM have the highest prediction capability. The model derived using DT has the lowest prediction capability. Compared to the logistic regression model, the prediction capability of the SVM models is slightly better. The prediction capability of the DT and NB models is lower.

Changes in Hip Fracture Epidemiology: Redistribution Between Ages, Genders and Fracture Types

Abstract: After several reports of increasing hip fracture incidence some studies have suggested a trend-break. In a previous study of hip fractures we forecast a 70% increase in the total number of fractures from 1985 up to year 2000. We therefore studied the incidence trend for the last 15 years and supply a new prognosis up to year 2010. We recorded all incident hip fractures treated in the county of Östergötland, Sweden (≈ 400 000 inhabitants) 1982–96. A total of 11 517 hip fractures in men and women aged 50 years and above were included in the study after cross-validation between a computerized register of radiologic investigations and the hospital records. The projected number of fractures up to year 2010 was estimated by a Poisson regression model, considering both age and year of fracture in every single year 1982–96 for the respective fracture type and gender, and applied to the projected population. The annual number of hip fractures increased by 39% in men and 25% in women during the study period. Amongst men, the age-adjusted incidence of cervical fractures increased from 188 to 220/100 000 and of trochanteric fractures from 138 to 170/100 000. In women the incidence of cervical fractures decreased from 462/100 000 to 418/100 000 and of trochanteric fractures from 407/100 000 to 361/100 000. Cervical/trochanteric fracture incidence rate ratio leveled off, and also the female/male fracture rate ratio declined. A prognosis assuming that the incidence development will continue as during 1982–96, and a population in agreement with the forecast, predicts that the total age- and sex-adjusted number of hip fractures will decrease by 11% up to year 2010 compared with 1996. In women and men, however, a decrease of 19% and an increase of 7% respectively were projected. If the age- and sex-specific incidence remains at the same level as at the end of the study period, no significant change in the total numbers will occur. A trend-break was thus found in hip fracture incidence for women but not for men. Whether this is due to therapeutic and/or preventive measures in women is unknown. According to the most probable scenario a substantial increase in male trochanteric fractures (36%) is expected up to 2010, while all other hip fractures in both genders will decrease by 4–32% resulting in a total reduction of 11%.

Randomised prostate cancer screening trial: 20 year follow-up

Objective To assess whether screening for prostate cancer reduces prostate cancer specific mortality. Design Population based randomised controlled trial. Setting Department of Urology, Norrköping, and the South-East Region Prostate Cancer Register. Participants All men aged 50-69 in the city of Norrköping, Sweden, identified in 1987 in the National Population Register (n=9026). Intervention From the study population, 1494 men were randomly allocated to be screened by including every sixth man from a list of dates of birth. These men were invited to be screened every third year from 1987 to 1996. On the first two occasions screening was done by digital rectal examination only. From 1993, this was combined with prostate specific antigen testing, with 4 µg/L as cut off. On the fourth occasion (1996), only men aged 69 or under at the time of the investigation were invited. Main outcome measures Data on tumour stage, grade, and treatment from the South East Region Prostate Cancer Register. Prostate cancer specific mortality up to 31 December 2008. Results In the four screenings from 1987 to 1996 attendance was 1161/1492 (78%), 957/1363 (70%), 895/1210 (74%), and 446/606 (74%), respectively. There were 85 cases (5.7%) of prostate cancer diagnosed in the screened group and 292 (3.9%) in the control group. The risk ratio for death from prostate cancer in the screening group was 1.16 (95% confidence interval 0.78 to 1.73). In a Cox proportional hazard analysis comparing prostate cancer specific survival in the control group with that in the screened group, the hazard ratio for death from prostate cancer was 1.23 (0.94 to 1.62; P=0.13). After adjustment for age at start of the study, the hazard ratio was 1.58 (1.06 to 2.36; P=0.024). Conclusions After 20 years of follow-up the rate of death from prostate cancer did not differ significantly between men in the screening group and those in the control group. Trial registration Current Controlled Trials, ISRCTN06342431.

Bone Mineral Density in Coeliac Disease

Patients with coeliac disease may have osteomalacia or osteoporosis, even in the absence of abdominal symptoms. Little is known about the effects of a gluten-free diet and villous restitution on the bone mineral density in adult patients with coeliac disease. Of the 288 patients with coeliac disease in our unit, 13 (5%) had persistent villous atrophy of the small bowel despite dietary recommendations over at least the previous 4 years. For each of these 13 patients, 1 or 2 controls with coeliac disease, matched for age, gender, menopausal state, and dermatitis herpetiformis, whose intestinal mucosa had normalized at least 4 years earlier, were identified (n = 17). Bone mineral density was measured in the forearm using single-photon absorptiometry and in the femoral neck and trochanter using dual-energy X-ray absorptiometry. Bone mineral density was reduced at all sites in patients with persistent villous atrophy compared with patients responsive to diet and healthy controls. Bone mineral density in patients responsive to diet did not differ from that in healthy controls. Persistent villous atrophy is associated with low bone mineral density, underlining the importance of keeping to a proper diet.

Bone Mineral Density in Normal Swedish Women

We examined 429 women, aged 20-80 years, randomly selected from the population register to establish normal values for bone mineral density (BMD) in Swedish women. BMD of the spine and hip was measured by dual-energy X-ray absorptiometry (DEXA; Hologic QDR 1000) and in the forearm by single photon absorptiometry (SPA; Molsgaard ND-1100). The recalled age of menarche was negatively correlated to BMD at all ages. There was no significant change in BMD from 20-49 years at any site except a slight decline at Wards triangle. Bone loss was rapid at all sites during the first decade after menopause. Thereafter, BMD declined slowly in the trochanter and total hip but more rapidly in the forearm, femoral neck, and Wards triangle. BMD in the spine even increased in the eighth decade probably due to osteoarthritis. The average change in forearm BMD during the 15 perimenopausal years comprising mean age for menopause +/- 2 SD (43-57 years) was -0.4% per year in premenopausal females and -1.6% per year in postmenopausal females. The corresponding annual percental change was, for the spine, +0.2 and -1.7; neck, -0.7 and -1.7; trochanter, +0.5 and -1.5; and Wards triangle, -0.1% and -2.2%, respectively. Our normal values for lumbar spine BMD prior to menopause did not differ from published values or the manufacturers normal values; however, our spine BMD values for the first decade after menopause were significantly lower (approximately 10%) than in other studies. Our femoral neck BMD values for younger women were, like those of several other groups, significantly lower than the manufacturers normal values, but our sample of young women in this study was small. The prevalence of osteoporosis, if defined as t score < -2.5 is highly dependent on the sampling of the reference population of young adult women, and also on the choice of skeletal site. Further studies on bone mineral density in healthy young adult women are needed.

Three Years' Follow-up of Bone Density in Adult Coeliac Disease: Significance of Secondary Hyperparathyroidism

BACKGROUND The mechanisms of disturbances in bone mineral density (BMD) in coeliac disease are not completely understood. The aim of this prospective study was to investigate the possible significance of secondary hyperparathyroidism (SHPT) with regard to BMD in patients with untreated coeliac disease. METHODS One hundred and five adult patients with untreated coeliac disease were examined for BMD and serum parathyroid hormone (PTH) concentration. BMD in the hip, lumbar spine, and forearm were examined up to 3 years after the introduction of a gluten-free diet. RESULTS SHPT was found in 27% (28 of 105) of the patients. In patients with SHPT serum levels of 25-hydroxy-vitamin D were lower and those of alkaline phosphatase higher than in patients with normal PTH, but ionized serum calcium did not differ between the two groups. BMD was more severely reduced in patients with SHPT. Although the BMD increment was more rapid in patients with than in those without SPTH, only in the latter group did mean BMD became normal after 1-3 years on a gluten-free diet (GFD). After 3 years on a GFD more than half of the patients with initial SHPT still had low BMD in both the hip and the forearm. Furthermore, in patients with SHPT the intestinal mucosa more often remained atrophic at the 1-year follow-up, despite good compliance with the diet. CONCLUSIONS Low BMD in patients with untreated coeliac disease is often associated with SHPT. After 3 years on a GFD the BMD remains low only in patients with initial SHPT. We therefore suggest that PTH should be measured when the diagnosis of coeliac disease is made, as an indicator of more serious intestinal disorder and complicating bone disease.Background: The mechanisms of disturbances in bone mineral density (BMD) in coeliac disease are not completely understood. The aim of this prospective study was to investigate the possible significance of secondary hyperparathyroidism (SHPT) with regard to BMD in patients with untreated coeliac disease. Methods: One hundred and five adult patients with untreated coeliac disease were examined for BMD and serum parathyroid hormone (PTH) concentration. BMD in the hip, lumbar spine, and forearm were examined up to 3 years after the introduction of a gluten-free diet. Results: SHPT was found in 27% (28 of 105) of the patients. In patients with SHPT serum levels of 25-hydroxy-vitamin D were lower and those of alkaline phosphatase higher than in patients with normal PTH, but ionized serum calcium did not differ between the two groups. BMD was more severely reduced in patients with SHPT. Although the BMD increment was more rapid in patients with than in those without SPTH, only in the latter group did mean BMD became normal after 1-3 years on a gluten-free diet (GFD). After 3 years on a GFD more than half of the patients with initial SHPT still had low BMD in both the hip and the forearm. Furthermore, in patients with SHPT the intestinal mucosa more often remained atrophic at the 1-year follow-up, despite good compliance with the diet. Conclusions: Low BMD in patients with untreated coeliac disease is often associated with SHPT. After 3 years on a GFD the BMD remains low only in patients with initial SHPT. We therefore suggest that PTH should be measured when the diagnosis of coeliac disease is made, as an indicator of more serious intestinal disorder and complicating bone disease.

Screening for carcinoma of the prostate by digital rectal examination in a randomly selected population.

OBJECTIVE--To study the acceptability, costs, psychosocial consequences, and organisation of screening for carcinoma of the prostate. DESIGN--A randomly selected population was personally invited for digital rectal examination by a urologist and a general practitioner. Further examinations were performed if induration was felt. Each man completed a questionnaire on his response to the examination. SETTING--General practices in the area of Norrköping. PATIENTS--1494 Men aged 50-69 randomly selected from a population of 9026. MAIN OUTCOME MEASURE--Prostates having a firm nodular consistency. RESULTS--Carcinoma of the prostate was suspected in 45 of 1163 patients examined; in 10 by the general practitioners, in 10 by the urologists, and in 25 by both. Forty four men had a fine needle aspiration biopsy, and carcinomas were found in 13 cases. Of these, one had been suspected by the general practitioner, four by urologists, and eight by both. The cost for each man was 11.60 pounds, and the cost for each case of carcinoma detected and treated by potentially curative methods was 2477 pounds. Of the 13 men with carcinoma, 10 underwent radical prostatectomy and one radiotherapy. One man had advanced disease and was given endocrine treatment, another was not treated. Only 193 men felt distress during the initial examination. Of the 44 men who had an aspiration biopsy, 25 experienced anxiety. CONCLUSIONS--Screening for carcinoma of the prostate by a urologist or a general practitioner using digital rectal examination is a cost effective method of early diagnosis. Whether such screening leads to prolonged survival, however, remains doubtful.

Bone Mineral Density in Diagnosis of Osteoporosis: Reference Population, Definition of Peak Bone Mass, and Measured Site Determine Prevalence

A population-based study was performed in order to compare different definitions of peak bone mass, and to apply the corresponding T-scores for different skeletal sites to a cohort of 70-yr-old women for studying the prevalence of osteoporosis. Bone mineral density (BMD) of the hip, lumbar spine, and forearm was measured by dual X-ray absorptiometry (Hologic 4500) in 296 women ages 16-31 yr and 210 women age 70 yr. Peak bone mass occurred in women in their early 20s at the proximal femur and at 28 and 31 yr at the spine and forearm, respectively. BMD cutoff levels were compared to machine-specific cutoff values for the different sites. When applied to our cohort of 70-yr-old women, the prevalence of osteoporosis at the total hip was 9-25%, depending on which peak bone mass the T-score of -2.5 was based. The prevalence in the spine was 28-33% and in the forearm 45-67%. Osteoporosis in at least one of the three measured sites was documented in 49-72% of the population sample. Our results show that the use of T-score to define osteoporosis results in a highly different prevalence rate in a given population depending on the reference population and the skeletal sites chosen for measurement.

Determination of alkaline phosphatase isoenzymes in serum by high-performance liquid chromatography with post-column reaction detection.

A weak anion-exchange high-performance liquid chromatographic procedure with post-column reaction detection for simultaneous determination of alkaline phosphatase (EC 3.1.3.1, ALP) isoenzymes is described. We identified six peaks with ALP isoenzyme activity in normal serum. The peaks were, in order of elution, one intestinal/bone, two bone and three liver ALP isoenzymes. This new assay with automatic injection, on-line post-column reaction detection and powerful integration data system could be of significant value in the routine clinical biochemistry laboratory. The advantages include improved sensitivity and selectivity over previous methods for the determination of ALP isoenzymes.