STATISTISK ANALYS AV ETT CALLCENTER - MODELLERING AV INKOMMANDE SAMTAL

Statistical theory suggests that call arrivals to a telephone exchange follow a Poisson process and that time between successive calls is exponentially distributed. Previous studies indicate that the average number of arrivals changes over time, and thus follow a time-inhomogeneous Poisson distribution. The purpose of this thesis is to assess if the characteristics of daily calls to a call center operated by ISS Facility Services AB (ISS), is consistent with statistical theory and previous studies. The methods used include the Kolmogorov-Smirnov test, computer simulation, the Ljung–Box test, and linear regression. Our results indicate that daily calls appear to be a time-inhomogeneous Poisson process, but that that the time between successive calls is not always exponentially distributed. However, it is still concluded that call arrivals to ISS can be modeled as a single time-inhomogeneous Poisson process. According to our simulations, the way in which calls are transmitted between the main telephone exchange and the different call centers should skew the probability distribution to the right. Yet, the results of the simulations do not seem to be consistent with the empirical distribution. Moreover, an increased call volume might also distort the distribution

Re-arthrodesis after primary ankle fusion: 134/1,716 cases from the Swedish Ankle Registry

Background and purpose — Arthrodesis is the most common treatment of severe ankle arthritis. Large studies on the occurrence of re-arthrodesis are few, especially with information in terms of risk. We used the National Swedish Ankle Registry to assess incidence and risk factors for re-arthrodesis. Patients and methods — In the Registry, we examined the occurrence of re-arthrodesis in 1,716 patients with a primary ankle arthrodesis. We also analyzed associations between the re-arthrodesis risk and sex, diagnosis, and surgical method. Results — The risk of first re-arthrodesis at 2.5 years was 7.4% and the rate at 9 years 7.8%. The risk following arthroscopic surgery with fixation by screws was 15%, which is statistically significantly higher than the 8% following the gold standard technique with open screw fixation, the 5% following fixation by intramedullary nailing, and the 3% following fixation by plate and screws. Patients with either idiopathic osteoarthritis or posttraumatic arthritis had a higher risk of re-arthrodesis than patients with rheumatoid arthritis. We could not find that the risk of re-arthrodesis was associated with sex. Interpretation — In Sweden, the re-arthrodesis risk varied by primary technique and was especially high after arthroscopic surgery. Reasons are unknown but poor surgical technique and/or surgeon inexperience may contribute, as may patient selection

Decline in FEV1 and hospitalized exacerbations in individuals with severe alpha-1 antitrypsin deficiency

Background and aim: The value of the forced expiratory volume in one second (FEV1) is useful in the diagnosis and prognosis of chronic obstructive pulmonary disease (COPD). Previous studies on lung function in individuals with severe alpha-1 antitrypsin deficiency (AATD) have shown a variable annual decline in FEV1 (∆FEV1). The aim of this study was to analyze ∆FEV1 and to identify risk factors for ∆FEV1 in individuals with severe AATD.Material and methods: Data on smoking habits, symptoms, results of lung function tests and exacerbations were obtained from the Swedish AATD Register and the Swedish National Patient Register (SNPR). The ∆FEV1 was analyzed by random-effects modeling and adjusted for age and FEV1 at baseline.Results: One hundred and four (9%) current smokers, 539 (48%) ex-smokers and 489 (43%) never-smokers were included in the study and followed-up from 1991 to 2016. A total of 584 (52%) individuals with severe AATD had COPD at inclusion. The median (IQR) annual severe exacerbation rate was 0.66 (1.4). The adjusted mean ∆FEV1 was significantly higher in the current smokers compared with the ex-smokers and never-smokers (70 [95% CI 56–83] vs 42 [95% CI 36–48] and 32 [95% CI 25–38) mL·yr−1,], in the middle–aged individuals compared with the young individuals (48 [95% CI 41–55] vs 32 [95% CI 18–45] mL·yr−1,), in the individuals with respiratory symptoms at inclusion compared with the asymptomatic individuals (46 [95% CI 40–52] vs 30 [95% CI 22–38]mL·yr−1,), and in the individuals with frequent exacerbations compared with those with infrequent exacerbations (57 [95% CI 47–68] vs 27 [95% CI 17–37] mL·yr−1,).Conclusion: Active smoking, age, respiratory symptoms at baseline and repeated severe exacerbations of COPD are factors associated with an accelerated decline of lung function in individuals with severe AATD

Association between circulating furin levels, obesity and pro-inflammatory markers in children

Aim: To, in children, investigate the associations between serum furin, obesity, overweight, body fat and circulating markers reflecting adipose tissue or systemic inflammation. Methods: We analysed furin, leptin, adipocyte fatty acid–binding protein, triglycerides, interleukin (IL)-6, IL-8 and C-reactive protein in serum from 166 children in the Pediatric Osteoporosis Prevention (POP) study collected at mean age (SD) 9.9 (0.6) years. Children were classified as low-to-normal weight, overweight or obese. Total body fat mass (kg), trunk fat mass (kg) and total body lean mass (kg) were measured by dual-energy X-ray absorptiometry. Body fat percentage (%) was calculated. Results: We found that circulating furin levels were higher in children with obesity and overweight compared with children with low-to-normal weight (p < 0.001 and p = 0.006, respectively). Also, there were positive correlations between circulating furin, total body fat mass, trunk fat mass, body fat percentage, triglycerides, adipokines and pro-inflammatory markers. Conclusion: This study indicates associations between furin, adiposity and a pro-inflammatory milieu in children. We suggest that future studies investigate the role of furin in fat tissue inflammation and associated increased risk of cardiometabolic diseases in children. Studies should also investigate whether higher furin levels could be a link between obesity and severe coronavirus disease 2019 in children

Serum Renin Levels Increase With Age in Boys Resulting in Higher Renin Levels in Young Men Compared to Young Women, and Soluble Angiotensin-Converting Enzyme 2 Correlates With Renin and Body Mass Index

Background: Age, sex, and body constitution may affect the shedding of membrane bound angiotensin-converting enzyme 2 (mACE2) and lead to a relative mACE2 deficiency. However, it is unclear if differences, reflected by serum renin levels, exist in the basal renin-angiotensin-system (RAS) between children and adults, boys, and girls as well as young women and young men. Furthermore, it remains to be investigated if renin and soluble ACE2 (sACE2) levels are correlated with body mass index (BMI) in children and young adults. The aim of this observational study was to assess age-and sex differences in serum renin, and the relationship between renin, soluble angiotensin-converting enzyme 2, and body mass index in a prospectively followed population-based cohort of children which were followed into young adulthood. Study Design: We analyzed renin and sACE2 in serum in a prospectively followed population-based cohort at 9.9 (0.6) [mean (SD)] (n = 173), 11.7 (0.6) (n = 156), 14.8 (0.8) (n = 149), 18.8 (0.3) (n = 93), and 23.5 (0.7) (n = 152) years of age. Height (cm) and weight (kg) was measured and body mass index (BMI) was calculated as weight (kg)/height (m)2. Sex-related differences in renin levels were calculated using analysis of covariance, adjusted for age. Correlations were assessed by calculating the correlation coefficient (R2) using a multivariable linear mixed model. Results: Both sexes had low renin levels up to 12 years of age. Thereafter renin levels increased more in boys than in girls. Males from the age of 15 had significantly higher levels than females (p < 0.001). There was a positive linear relationship between renin and sACE2 levels in male and female subjects (p < 0.001), and between sACE2 levels and BMI in males (p < 0.001). Conclusion: Renin levels increase with age, are higher in men than in women since around puberty, and are correlated with sACE2 levels. Furthermore, sACE2 levels are correlated with body mass index in males. These findings indicate that high renin levels in males and females and a high BMI in males may activate pathways which increase the shedding of mACE2, with possible implications for the risk of severe coronavirus disease 2019

Outcomes of trabecular metal total ankle replacement : a longitudinal observational cohort study of 239 consecutive cases from the Swedish Ankle Registry

Background and purpose — Information on outcomes after some modern total ankle replacement (TAR) designs is scarce. We therefore examined outcomes after trabecular metal (TM) TAR in Sweden by use of data from the national registry. Patients and methods — On December 31, 2020, 239 primary TM TARs had been reported to the Swedish Ankle Registry. We analyzed prosthesis survival probability, using exchange or permanent extraction of components as end-point for 239 protheses with mean follow-up of 2.2 years (0.1–6.6), risk of revision, as well as patient-reported outcome measures (SEFAS/EQ-5D/EQ-VAS) and satisfaction with surgery. Results — 7/239 prostheses (3%) had been revised by December 31, 2020. We found an overall prosthesis survival probability of 95% (95% CI 89–98) after 3 years. 2 years after surgery 81% of the answering patients were satisfied or very satisfied with surgery and patients reported median SEFAS 36 (max 48), EQ-5D 0.90 (max 1), and EQ-VAS 80 (max 100). Interpretation — We found short-to mid-term outcomes after TM TAR to be at least as good as after other TAR designs regarding prosthesis survival and patient-reported satisfaction

Association between circulating furin levels, obesity and pro‐inflammatory markers in children

Aim: To, in children, investigate the associations between serum furin, obesity, overweight, body fat and circulating markers reflecting adipose tissue or systemic inflammation. Methods: We analysed furin, leptin, adipocyte fatty acid–binding protein, triglycerides, interleukin (IL)-6, IL-8 and C-reactive protein in serum from 166 children in the Pediatric Osteoporosis Prevention (POP) study collected at mean age (SD) 9.9 (0.6) years. Children were classified as low-to-normal weight, overweight or obese. Total body fat mass (kg), trunk fat mass (kg) and total body lean mass (kg) were measured by dual-energy X-ray absorptiometry. Body fat percentage (%) was calculated. Results: We found that circulating furin levels were higher in children with obesity and overweight compared with children with low-to-normal weight (p < 0.001 and p = 0.006, respectively). Also, there were positive correlations between circulating furin, total body fat mass, trunk fat mass, body fat percentage, triglycerides, adipokines and pro-inflammatory markers. Conclusion: This study indicates associations between furin, adiposity and a pro-inflammatory milieu in children. We suggest that future studies investigate the role of furin in fat tissue inflammation and associated increased risk of cardiometabolic diseases in children. Studies should also investigate whether higher furin levels could be a link between obesity and severe coronavirus disease 2019 in children

Physical Activity at Growth Induce Bone Mass Benefits Into Adulthood : A 15-Year Prospective Controlled Study

Daily school physical activity (PA) improves musculoskeletal traits. Whether or not benefits remain in adulthood is debated. We included in this study 131 children that took part in an intervention with 40 minutes of PA per school day (200 minutes per week) from age 6 to 9 years (grade one) to age 14 to 16 years (grade nine), whereas 78 children continued with national recommended school physical education of 60 minutes per week. Measurements were done with dual-energy X-ray absorptiometry (bone mineral content [BMC], bone mineral density [BMD], and bone area), and a computerized knee dynamometer (peak torque muscle strength) at study start, at the end of the intervention, and 7 years after the intervention. Group differences from study start and end of the intervention to 7 years thereafter were estimated by analyses of covariance (adjusted for sex and follow-up time). Musculoskeletal gains from study start to 7 years after termination of the intervention were higher in the intervention group (total body less head BMC +182.5 g [95% confidence interval {CI}, 55.1–309.9] and BMD +0.03 g/cm2 [95% CI, 0.003–0.05], femoral neck area + 0.2 cm2 [95% CI, 0.1–0.4], and knee flexion peak torque muscle strength at 60 degrees per second +9.2 Nm [95% CI, 2.9–15.5]). There was no attenuation during the 7 years that followed termination of the intervention (all group comparisons p > 0.05). Benefits in musculoskeletal gains remain 7 years after termination of a daily school-based PA program, without attenuation after termination of the program. Daily school PA may counteract low bone mass and inferior muscle strength in adulthood

Musculoskeletal Benefits from a Physical Activity Program in Primary School are Retained 4 Years after the Program is Terminated

Daily school physical activity (PA) improves musculoskeletal traits. This study evaluates whether the benefits remain 4 years after the intervention. We followed 45 boys and 36 girls who had had 40 min PA/school day during the nine compulsory school years and 21 boys and 22 girls who had had 60 min PA/school week (reference), with measurements at baseline and 4 years after the program terminated. Bone mineral content (BMC; g) and bone mineral density (BMD; g/cm2) were measured by dual-energy X-ray absorptiometry and knee flexion peak torque relative to total body weight (PTflexTBW) at a speed of 180 degrees/second with a computerized dynamometer. Group differences are presented as mean differences (adjusted for sex and duration of follow-up period) with 95% confidence intervals. The total gain bone mass [mean difference in spine BMC +32.0 g (14.6, 49.4) and in arms BMD of +0.06 g/cm2 (0.02, 0.09)] and gain in muscle strength [mean difference in PTflex180TBW +12.1 (2.0, 22.2)] were greater in the intervention than in the control group. There are still 4 years after the intervention indications of benefits in both bone mass and muscle strength gain. Daily school PA may counteract low bone mass and inferior muscle strength in adult life. ClinicalTrials.gov.NCT000633828 retrospectively registered 2008-11-0

Time trends in pediatric hand fracture incidence in Malmö, Sweden, 1950–2016

Background: The hand is the second most fractured region in children. It is therefore important to update fracture epidemiology to be able to identify time trends for adequate health care planning. This study reports pediatric hand fracture incidence 2014–2016 and, using published data, also long-term time trends in 1950–2016. Patients and methods: The Swedish city of Malmö, with 328,494 inhabitants in 2016, has only one hospital. We used the hospital radiological archive, medical charts, and diagnosis registry to identify hand fractures in city residents < 16 years in 2014–2016. These data were compared to those from three published studies that evaluated periods in 1950–2006. Differences between two periods were calculated as both unadjusted and age- and sex-adjusted incident rate ratios (IRR) with 95% confidence intervals (95% CI). We used joinpoint regression to estimate time trends during the entire period and present annual percent changes (APC) with 95% CI. Results: In 2014–2016 phalangeal fractures accounted for 71% of all hand fractures, metacarpal fractures for 24%, and carpal fractures for 5%. We identified 615 hand fractures (419 in boys and 196 in girls) during 181,617 person-years in 2014–2016, resulting in an unadjusted pediatric hand fracture incidence of 339/100,000 person-years (boys 452/100,000 person-years and girls 220/100,000 person-years). The age-adjusted incidence 2014–2016 was similar to 2005–2006, the most recently evaluated period (IRR in boys 0.9; 95% CI 0.8 to 1.01, and in girls 1.0; 95% CI 0.8 to 1.2). Looking at the entire period 1950–2016, we found that age-adjusted incidence increased in 1950–1979, in boys by APC + 3.8%; 95% CI 3.0 to 4.5 and in girls by + 3.9%; 95% CI 2.8 to 5.0, but decreased in 1979–2016, in boys by − 0.7%; 95% CI − 1.4 to − 0.003, and girls by − 1.3%; 95% CI − 2.4 to − 0.1. Conclusions: Phalangeal fractures accounted for about three quarters of all hand fractures. The age-adjusted hand fracture incidence increased in both sexes in 1950–1979 and decreased in 1979–2016. Level of evidence: II