Guidelines for Canadian bariatric surgical and medical centres: a statement from the Canadian Association of Bariatric Physicians and Surgeons.

SummaryThe goal of this statement is to offer standardization in bariatric care across Canada, to provide patients with optimal access to obesity treatment and potentially improve outcomes by reducing complications, length of hospital stay and readmission rate. The definition of Canadian standards also aims to promote a comprehensive, multidisciplinary approach to patients with obesity, to define the minimal qualifications for surgical and medical training and to offer credentialling for bariatric surgical and medical centres. In addition, we emphasize the importance of developing a national registry for the assessment of quality of care across the country and to evaluate outcomes of long-term treatment. These recommendations are based on expert opinion as well as the most recent clinical evidence.

Probability Distributome: A Web Computational Infrastructure for Exploring the Properties, Interrelations, and Applications of Probability Distributions.

Probability distributions are useful for modeling, simulation, analysis, and inference on varieties of natural processes and physical phenomena. There are uncountably many probability distributions. However, a few dozen families of distributions are commonly defined and are frequently used in practice for problem solving, experimental applications, and theoretical studies. In this paper, we present a new computational and graphical infrastructure, the Distributome, which facilitates the discovery, exploration and application of diverse spectra of probability distributions. The extensible Distributome infrastructure provides interfaces for (human and machine) traversal, search, and navigation of all common probability distributions. It also enables distribution modeling, applications, investigation of inter-distribution relations, as well as their analytical representations and computational utilization. The entire Distributome framework is designed and implemented as an open-source, community-built, and Internet-accessible infrastructure. It is portable, extensible and compatible with HTML5 and Web2.0 standards (http://Distributome.org). We demonstrate two types of applications of the probability Distributome resources: computational research and science education. The Distributome tools may be employed to address five complementary computational modeling applications (simulation, data-analysis and inference, model-fitting, examination of the analytical, mathematical and computational properties of specific probability distributions, and exploration of the inter-distributional relations). Many high school and college science, technology, engineering and mathematics (STEM) courses may be enriched by the use of modern pedagogical approaches and technology-enhanced methods. The Distributome resources provide enhancements for blended STEM education by improving student motivation, augmenting the classical curriculum with interactive webapps, and overhauling the learning assessment protocols.

In vivo precision of the GE lunar iDXA for the assessment of lumbar spine, total hip, femoral neck, and total body bone mineral density in severely obese patients.

No study has evaluated the precision of the GE Lunar iDXATM (GE Healthcare) in measuring bone mineral density (BMD) among severely obese patients. The purpose of the study was to evaluate the precision of the GE Lunar iDXATM for assessing BMD, including the lumbar spine L1-L4, L2-L4, the total hip, femoral neck, and total body in a severely obese population (body mass index [BMI]>40 kg/m(2)). Sixty-four severely obese participants with a mean age of 46 ± 11 yr, BMI of 49 ± 6 kg/m(2), and a mean body mass of 136.8 ± 20.4 kg took part in this investigation. Two consecutive iDXA scans (with repositioning) of the total body (total body BMD [TBBMD]), lumbar spine (L1-L4 and L2-L4), total hip (total hip BMD [THBMD]), and femoral neck (femoral neck BMD [FNBMD]) were conducted for each participant. The coefficient of variation (CV), the root mean square (RMS) averages of standard deviations of repeated measurements, the corresponding 95% least significant change, and intraclass correlations (ICCs) were calculated. In addition, analysis of bias and coefficients of repeatability were calculated. The results showed a high level of precision for total body (TBBMD), lumbar spine (L1-L4), and total hip (THBMD) with values of RMS: 0.013, 0.014, and 0.011 g/cm(2); CV: 0.97%, 1.05%, and 0.99%, respectively. Precision error for the femoral neck was 2.34% (RMS: 0.025 g/cm(2)) but still represented high reproducibility. ICCs in all dual-energy X-ray absorptiometry measurements were 0.99 with FNBMD having the lowest at 0.98. Coefficients of repeatability for THBMD, FNBMD, L1-L4, L2-L4, and TBBMD were 0.0312, 0.0688, 0.0383, 0.0493, and 0.0312 g/cm(2), respectively. The Lunar iDXA demonstrated excellent precision for BMD measurements and is the first study to assess reproducibility of the GE Lunar iDXA with severely obese adults.

Laparoscopic bariatric surgery can be performed safely in secondary health care centres with a dedicated service corridor to an affiliated tertiary health care centre.

BACKGROUND: Canada needs to increase capacity for bariatric surgery to reduce the wait for this cost-effective, life-saving surgery. The aim of this study was to test whether laparoscopic bariatric surgery, including gastric bypass, can be delivered safely in secondary health care centres (SHCCs). METHODS: In this prospective cohort study, patients received bariatric surgery at an SHCC that had no intensive care unit but had a dedicated operating room and ward teams and a patient-monitoring environment. Patients with life-threatening complications were transferred to an affiliated tertiary health care centre (THCC) via a dedicated "service corridor." RESULTS: In all, 830 patients were treated: 676 at the SHCC and 154 at the THCC. Gastric bypass was performed in 85.4%, gastric band in 11.1% and gastric sleeve in 3.5%. The body mass index (BMI) was significantly higher in the THCC than the SHCC group (mean 54.4 [standard deviation (SD) 9.7] v. 47.5 [SD 7.4]). Obesity-associated diseases were similar between the groups. Major complications occurred in 2.6% of SHCC patients and 1.7% of THCC patients. Seven patients (1%) required direct transfer to the THCC, and all were treated successfully. There were 2 deaths (1.3%) in the THCC and none in the SHCC groups (combined mortality 0.2%). Weight loss was equivalent up to the fourth year of the study. CONCLUSION: With proper patient selection, a dedicated health care team and a service corridor to an affiliated THCC, laparoscopic bariatric surgery, including gastric bypass can be performed safely in SHCCs. Further study is needed to determine whether the model can be applied across Canada.

CONTEXTE: Le Canada doit accroître sa capacité en chirurgie bariatrique afin de réduire les temps d'attente pour cette intervention rentable qui sauve des vies. Le but de cette étude était de vérifier si la chirurgie bariatrique laparoscopique, y compris le pontage gastrique laparoscopique, peut se pratiquer en toute sécurité dans les centres hospitaliers de soins de deuxième ligne (CHDL). MÉTHODES: Dans cette étude de cohorte prospective, les patients ont subi une chirurgie bariatrique dans un CHDL sans unité de soins intensifs mais pourvu d'un bloc opératoire et d'équipes soignantes spécialisées, ainsi que d'un système de surveillance des patients. Les patients qui ont présenté des complications gravissimes ont été transférés dans un centre hospitalier de soins tertiaires (CHST), par le bais d'un « corridor de service ¼ réservé. RÉSULTANTS: En tout, 830 patients ont subi le traitement; 676 au CHDL et 154 au CHST. On a procédé par pontage gastrique chez 85,4 % patients, pose d'un anneau gastrique chez 11,1 % et gastrectomie longitudinale en manchon (gastric sleeve) chez 3,5 % des patients. L'indice de masse corporelle (IMC) était significativement plus élevé dans le groupe transféré au CHST que dans le groupe traité au CHDL (moyenne 54,4 [écart-type (ET) 9,7 c. 47,5 [ET 7,4]). Les maladies associées à l'obésité étaient similaires entre les groupes. Des complications majeures sont surve - nues chez 2,6 % des patients du CHDL et 1,7 % des patients du CHST. Sept patients (1 %) ont dû être transférés directement au CHST et ils ont tous été traités avec succès. On a déploré 2 décès (1,3 %) dans le groupe du CHST; aucun n'est survenu chez les patients du CHDL (mortalité combinée 0,2 %). La perte de poids a été équivalente jusqu'à la quatrième année de l'étude. CONCLUSIONS: Avec une sélection adéquate des patients, une équipe soignante spécialisée et un corridor de service vers un CHST affilié, il est possible d'effectuer sécuritairement des chirurgies bariatriques laparoscopiques, y compris par pontage gastrique, dans les CHDL. Il faudra approfondir la recherche pour déterminer si ce modèle peut être appliqué partout au Canada.

Web-based tools for modelling and analysis of multivariate data: California ozone pollution activity.

This article presents a hands-on web-based activity motivated by the relation between human health and ozone pollution in California. This case study is based on multivariate data collected monthly at 20 locations in California between 1980 and 2006. Several strategies and tools for data interrogation and exploratory data analysis, model fitting and statistical inference on these data are presented. All components of this case study (data, tools, activity) are freely available online at: http://wiki.stat.ucla.edu/socr/index.php/SOCR_MotionCharts_CAOzoneData. Several types of exploratory (motion charts, box-and-whisker plots, spider charts) and quantitative (inference, regression, analysis of variance (ANOVA)) data analyses tools are demonstrated. Two specific human health related questions (temporal and geographic effects of ozone pollution) are discussed as motivational challenges.

SOCR Motion Charts: An Efficient, Open-Source, Interactive and Dynamic Applet for Visualizing Longitudinal Multivariate Data.

The amount, complexity and provenance of data have dramatically increased in the past five years. Visualization of observed and simulated data is a critical component of any social, environmental, biomedical or scientific quest. Dynamic, exploratory and interactive visualization of multivariate data, without preprocessing by dimensionality reduction, remains a nearly insurmountable challenge. The Statistics Online Computational Resource (www.SOCR.ucla.edu) provides portable online aids for probability and statistics education, technology-based instruction and statistical computing. We have developed a new Java-based infrastructure, SOCR Motion Charts, for discovery-based exploratory analysis of multivariate data. This interactive data visualization tool enables the visualization of high-dimensional longitudinal data. SOCR Motion Charts allows mapping of ordinal, nominal and quantitative variables onto time, 2D axes, size, colors, glyphs and appearance characteristics, which facilitates the interactive display of multidimensional data. We validated this new visualization paradigm using several publicly available multivariate datasets including Ice-Thickness, Housing Prices, Consumer Price Index, and California Ozone Data. SOCR Motion Charts is designed using object-oriented programming, implemented as a Java Web-applet and is available to the entire community on the web at www.socr.ucla.edu/SOCR_MotionCharts. It can be used as an instructional tool for rendering and interrogating high-dimensional data in the classroom, as well as a research tool for exploratory data analysis.

Small bowel obstruction due to retrograde intussusception after laparoscopic Roux-en-Y gastric bypass.

A 39-year-old female presented 4 years after laparoscopic Roux-en-Y gastric bypass with colicky abdominal pain, vomiting and inability to pass flatus. She had lost 100% of her excess weight after surgery and her body mass index had dropped from 46 to 22 kg/m(2). At exploration, a retrograde intussusception of the small bowel was noted distally to the jejunojejunostomy causing obstruction of the alimentary and biliopancreatic limb and gastric remnant. The intussusception was irreducible with signs of bowel ischaemia and required excision. The patient made an uneventful recovery. Colicky abdominal pain in a bariatric patient persisting more than 4 h mandates urgent investigation with abdominal computed tomography. Emergency care doctors should be aware of this specific complication in bariatric patients and seek expert advice.

Impact of obesity and bariatric surgery on survival.

Bariatric surgery is the only reliable treatment that offers sustained, long-term weight loss. This results in cure or improvement in almost all of the obesity-associated diseases and translates into reduction in the relative risk of death or increased longevity of the operated morbidly obese population. Since the treatment of obesity-associated conditions is very costly, bariatric surgery also results in significant reductions in healthcare costs with a return on investment of 3 years. It is not just weight loss, it is health gain.

Five-year outcomes of laparoscopic adjustable gastric banding and laparoscopic Roux-en-Y gastric bypass in a comprehensive bariatric surgery program in Canada.

BACKGROUND: Bariatric surgery remains the most effective modality to induce sustainable weight loss in the morbidly obese. Our aim was to compare outcomes between the laparoscopic Roux-en-Y gastric bypass (LRYGBP) and the laparoscopic adjustable gastric banding device (LAGBD) method with 5-year follow-up in a Canadian bariatric surgery centre. METHODS: This is a retrospective outcomes analysis of 1035 laparoscopic bariatric procedures performed over 7 years. We extracted data from our prospectively collected bariatric surgery registry from Feb. 1, 2002, to Jun. 30, 2008. We evaluated patient demographics, weight loss, complications, mortality and need for revision surgery by procedure type. RESULTS: We examined outcomes in 149 (14.4%) LAGBD and 886 (85.6%) LRYGBP procedures. The mean body mass index (BMI) was significantly higher in the LRYGBP group (50.9, standard deviation [SD] 8.9, v. 45.0, SD 6.7) whereas age and sex ratio were the same. There were 3 deaths (0.3%) in the LRYGBP group and no deaths in the LAGBD group. Sixteen patients (10.8%) in the LAGBD group needed conversion to LRYGBP because of poor weight loss, band intolerance, band erosion or slippage, and 6 patients (0.7%) in the LRYGBP group required revision because of inability to achieve the desired weight loss. The percent excess-weight loss was 41, 49, 59, 60 and 61 at 1, 2, 3, 4 and 5 years postsurgery for the LAGBD patients who kept their band, and 70, 79, 79, 79 and 75 for the LRYGBP patients. CONCLUSION: Laparoscopic weight loss surgery can be performed safely with acceptable mortality. Our study suggests superior weight loss and low revision requirement for the LRYGBP, making this a more durable procedure in a publicly funded health care system.

Bariatric surgery waiting times in Canada.

BACKGROUND: Severe obesity is reaching epidemic proportions throughout the world, including Canada. The only permanent treatment of severe or morbid obesity is bariatric surgery. Access to bariatric surgery is very limited in Canada. We sought to collect accurate data on waiting times for the procedure. METHODS: We carried out a survey of members of the Canadian Association of Bariatric Physicians and Surgeons and performed a more detailed analysis within Quebec and at one Canadian bariatric surgery centre where a prospectively collected bariatric surgery registry has been maintained since 1983. RESULTS: The survey response rate was 85%. All centres determined whether patients were eligible for bariatric surgery based on the National Institutes of Health criteria. Patients entered the queue as "office contacts" and moved through the queue, with the exit point being completion of the procedure. In 2007, a total of 6783 patients were waiting for bariatric surgery and 1313 procedures were performed in Canada. Assuming these trends are maintained, the calculated average waiting time for bariatric surgery in Canada is just over 5 years (6783/1313). The Fraser Institute and the Wait Times Alliance benchmarks for reasonable surgical waiting times vary from 8 weeks for cancer surgery to 18 months for cosmetic surgery. At one Canadian centre, 12 patients died while waiting for bariatric surgery. CONCLUSION: The waiting times for bariatric surgery are the longest of any surgically treated condition. Given the significant reduction in the relative risk of death with bariatric surgery (40%-89% depending on the study), the current waiting times for the procedure in Canada are unacceptable.

Law of Large Numbers: the Theory, Applications and Technology-based Education.

Modern approaches for technology-based blended education utilize a variety of recently developed novel pedagogical, computational and network resources. Such attempts employ technology to deliver integrated, dynamically-linked, interactive-content and heterogeneous learning environments, which may improve student comprehension and information retention. In this paper, we describe one such innovative effort of using technological tools to expose students in probability and statistics courses to the theory, practice and usability of the Law of Large Numbers (LLN). We base our approach on integrating pedagogical instruments with the computational libraries developed by the Statistics Online Computational Resource (www.SOCR.ucla.edu). To achieve this merger we designed a new interactive Java applet and a corresponding demonstration activity that illustrate the concept and the applications of the LLN. The LLN applet and activity have common goals - to provide graphical representation of the LLN principle, build lasting student intuition and present the common misconceptions about the law of large numbers. Both the SOCR LLN applet and activity are freely available online to the community to test, validate and extend (Applet: http://socr.ucla.edu/htmls/exp/Coin_Toss_LLN_Experiment.html, and Activity: http://wiki.stat.ucla.edu/socr/index.php/SOCR_EduMaterials_Activities_LLN).

Compensatory exercise hyperventilation is restored in the morbidly obese after bariatric surgery.

BACKGROUND: Morbidly obese individuals may have poor compensatory hyperventilation during exercise. The objective was to examine pulmonary gas exchange and the compensatory hyperventilatory response during exercise pre- and post-weight reduction surgery in obese subjects. METHODS: Fifteen patients (age=39+/-8 years, body mass index=47+/-6 kg/m2), with an excess weight of 69+/-17 kg, were recruited. Pulmonary function at rest was assessed and arterial-blood gases were sampled at rest and all levels of exercise pre- and 10+/-3 weeks postsurgery. RESULTS: There was a loss of excess weight 21+/-6 kg (p<0.01). Waist and hip circumference decreased by 13+/-9 and 8+/-7 cm, respectively (p<0.01). Prior to surgery, there was no compensatory hyperventilation between rest and peak exercise as arterial PCO2 (PaCO2) remained unchanged (37+/-3 mm Hg). However, postsurgery, there was compensatory hyperventilation as PaCO2 decreased to 33+/-2 mm Hg at peak exercise (p<0.01), with no change in peak oxygen consumption (VO2peak in L/min). Multiple linear regression revealed that the restored ventilatory response to exercise was most strongly associated with the reduction in overall fat mass (adjusted r2=0.25; p=0.03). Total weight loss of 21 kg induces adequate compensatory hyperventilation that begins to show at about 50% of VO2peak, resulting in improved gas exchange at moderate to peak exercise intensities. CONCLUSION: Improvement in compensatory hyperventilation is most closely related to loss in overall fat mass.

Alveolar-membrane diffusing capacity improves in the morbidly obese after bariatric surgery.

BACKGROUND: Morbidly obese individuals may have impaired alveolar-membrane diffusing capacity (DmCO). The purpose of this study was to measure pulmonary diffusing capacity for NO (DLNO) as an index of DmCO pre- and postbariatric surgery in the morbidly obese. METHODS: Twenty-one patients [age = 40 +/- 9 years, body mass index (BMI) = 48.5 +/- 7.2 kg/m2] with an excess weight of 72 +/- 17 kg scheduled for bariatric surgery were recruited. Pulmonary function and arterial blood-gases were measured pre- and postsurgery. RESULTS: DmCO was 88 +/- 23% of predicted before surgery (p < 0.05). There was loss in BMI and excess weight of 7.7 +/- 2.0 kg/m2 and 31 +/- 8%, respectively. Because DmCO = DLNO/2.42, the increase in DLNO postsurgery resulted in a normalization of the predicted DmCO to 97 +/- 29% predicted, or an improvement of DLNO by 11 +/- 18 (95% CI = 3.5, 19.1; p = 0.01) milliliters per minute per millimeter of mercury without any improvement in DLCO. The DLNO/DLCO ratio and alveolar volume both increased, respectively (p < 0.05), and pulmonary capillary blood volume to DmCO ratio decreased postsurgery (p < 0.01). Multiple linear regression revealed that the change in DLNO was most strongly associated with changes in alveolar volume and the waist-to-hip ratio (adjusted r2 = 0.76; p < 0.001) and was not related to the reduction in the alveolar-to-arterial PO2 difference. CONCLUSION: Alveolar-membrane diffusion normalizes within 10 weeks after bariatric surgery. This is likely due to the increase in alveolar volume from the reduction in the waist-to-hip ratio.

Preoperative gender differences in pulmonary gas exchange in morbidly obese subjects.

BACKGROUND: Morbidly obese men may have poorer pulmonary gas exchange compared to morbidly obese women (see Zavorsky et al., Chest 131:362-367, 2007). The purpose was to compare pulmonary gas exchange in morbidly obese men and women at rest and throughout exercise. METHODS: Twenty-five women (age=38+/-10 years, 164+/-7 cm, body mass index or BMI = 51+/-7 kg/m(2), peak oxygen consumption or VO(2peak)=2.0+/-0.4 l/min) and 17 men (age=43+/-9 years, 178+/-7 cm, BMI=50+/-10 kg/m(2), VO(2peak)=2.6+/-0.8 l/min) were recruited to perform a graded exercise test on a cycle ergometer with temperature-corrected arterial blood-gas samples taken at rest and every minute of exercise, including peak exercise. RESULTS: At rest, women were 98% predicted for pulmonary diffusion compared to 88% predicted in men. At rest, women had better pulmonary gas exchange compared to the men which was related to women having a lower waist-to-hip ratio (WHR; p<0.01). Only 20% of the subjects had an excessive alveolar-to-arterial oxygen partial pressure difference (>or=25 mmHg) at peak exercise, but 75% of the subjects showed inadequate compensatory hyperventilation at peak exercise (arterial carbon dioxide pressure >35 mmHg), and both were not different between genders. CONCLUSION: At rest, morbidly obese men have poorer pulmonary gas exchange and pulmonary diffusion compared to morbidly obese women. The better gas exchange in women is related to the lower WHR in the women. During exercise, few subjects showed disturbances in pulmonary gas exchange despite demonstrating poor compensatory hyperventilation at peak exercise.

Anastomotic leaks after bariatric surgery: it is the host response that matters.

BACKGROUND: Anastomotic leaks after bariatric surgery can lead to severe complications and adverse outcomes. We tested the hypothesis that not all patients with an anastomotic leak after bariatric surgery present with clinical symptoms and that their outcome is dependent on the aggressiveness of the host inflammatory response. METHODS: This was a retrospective analysis of prospectively collected clinical data from 2384 bariatric surgeries from 1983 to 2006. All anastomotic leaks were identified from the database, and the vital signs, hematologic and biochemical data, mode of diagnosis, treatment, and outcome were recorded and analyzed. RESULTS: We identified 55 anastomotic leaks (2.3%) at a median of 4 days (range 1-26) after surgery. In 37 patients (67.3%), the leaks were identified at a median of 5 days (range 1-26) postoperatively because of clinical signs and symptoms of a systemic inflammatory response (SIRS leaks). In contrast, in 18 patients (32.7%), the leaks were identified at a median of 1.5 days (range 1-16) postoperatively only after routine contrast studies (non-SIRS leaks). Treatment included antibiotics and open drainage in 41.8%, laparoscopic drainage in 21.8%, computed tomography-guided drainage in 12.7%, conservative treatment in 14.5%, and other in 9.2%. All 6 deaths (4 men and 2 women, 10.9%) occurred in the SIRS group. Using logistic regression analysis, temperature (inflammatory response) and body mass index were independent predictors of mortality. CONCLUSION: The results of our study have shown that one third of patients with anastomotic leaks after bariatric surgery present with minimal clinical symptoms (non-SIRS) and are only detected if contrast studies are performed. Such leaks are unlikely to lead to death. Two thirds of patients with anastomotic leaks present with a systemic inflammatory response to the leak. Such leaks require urgent treatment that might not always prevent death.

Use of critical care resources after laparoscopic gastric bypass: effect on respiratory complications.

BACKGROUND: Before 2005, all subjects undergoing laparoscopic gastric bypass with a body mass index >50 kg/m(2), age >40 years, and documented obstructive sleep apnea (OSA) were admitted to the intensive care unit (ICU) in our institution. Starting in January 2005, only patients with a body mass index >60 kg/m(2) and severe OSA were admitted. This study assessed the incidence of respiratory complications in patients undergoing laparoscopic gastric bypass before and after implementation of the new ICU admission criteria. METHODS: The records of the laparoscopic gastric bypass patients who had undergone laparoscopic gastric bypass from January 2004 to December 2005 were reviewed regarding demographic data (age, sex, body mass index, American Society of Anesthesiologists classification); OSA; use of home continuous positive airway pressure; length of stay in postanesthesia care unit, ICU, and hospital; postoperative ventilation and hypoxemia (oxygen saturation <90%), and unplanned ICU admission. RESULTS: A total of 250 charts were analyzed (122 from 2004 and 128 from 2005). The demographic data were comparable between the 2 groups. Although OSA was more frequent in the 2004 than in the 2005 cohort (P = .02), the incidence of OSA requiring home continuous positive airway pressure was comparable (P = .47). The length of hospital stay was greater in 2004 than in 2005 (P = .003). More patients were admitted to the ICU in 2004 (P <.001). All unplanned ICU admissions were because of surgical anastomotic/staple line leaks (7 patients in 2004 versus 0 in 2005; P = .006). Overall, the incidence of postoperative respiratory complications was low (6% in 2004 and 4% in 2005) and comparable in both groups. CONCLUSION: Limiting ICU admission after laparoscopic gastric bypass to patients with a body mass index >60 kg/m(2) and severe OSA did not increase the overall incidence of postoperative respiratory complications or hospital stay.

Bariatric surgery reduces cancer risk in morbidly obese patients.

BACKGROUND: To assess the effect of bariatric surgery on the cancer risk of patients with morbid obesity because evidence is mounting of an association between obesity and cancer. METHODS: We performed an observational 2-cohort study. The treatment cohort (n = 1035) included patients who had undergone bariatric surgery from 1986 to 2002. The control group (n = 5746) included age- and gender-matched morbidly obese patients who had not undergone weight-reduction surgery and who were identified from a single-payor administrative database. The subjects with physician or hospital visits for a cancer-related diagnosis or treatment within the 6 months previous to the beginning of the study were excluded. The cohorts were followed up for a maximum of 5 years from study inception. RESULTS: Bariatric surgery resulted in a significant reduction in the mean percentage of excess weight loss (67.1%, P <.001). The surgery patients had significantly fewer physician/hospital visits for all cancer diagnoses (n = 21, 2.0%) compared with the controls (n = 487, 8.45%; relative risk .22, 95% confidence interval .143-.347; P = .001). The physician/hospital visits for common cancers such as breast cancer were significantly reduced in the surgery group (P = .001). For all other cancers, the physician/hospital visits showed a trend toward being lower in the surgery group. Because of the low frequencies, statistical significance could not be demonstrated for individual cancer diagnoses. CONCLUSION: The data suggest that bariatric surgery improves the cancer outcomes in some morbidly obese patients.

Pedagogical Utilization and Assessment of the Statistic Online Computational Resource in Introductory Probability and Statistics Courses.

Technology-based instruction represents a new recent pedagogical paradigm that is rooted in the realization that new generations are much more comfortable with, and excited about, new technologies. The rapid technological advancement over the past decade has fueled an enormous demand for the integration of modern networking, informational and computational tools with classical pedagogical instruments. Consequently, teaching with technology typically involves utilizing a variety of IT and multimedia resources for online learning, course management, electronic course materials, and novel tools of communication, engagement, experimental, critical thinking and assessment.The NSF-funded Statistics Online Computational Resource (SOCR) provides a number of interactive tools for enhancing instruction in various undergraduate and graduate courses in probability and statistics. These resources include online instructional materials, statistical calculators, interactive graphical user interfaces, computational and simulation applets, tools for data analysis and visualization. The tools provided as part of SOCR include conceptual simulations and statistical computing interfaces, which are designed to bridge between the introductory and the more advanced computational and applied probability and statistics courses. In this manuscript, we describe our designs for utilizing SOCR technology in instruction in a recent study. In addition, present the results of the effectiveness of using SOCR tools at two different course intensity levels on three outcome measures: exam scores, student satisfaction and choice of technology to complete assignments. Learning styles assessment was completed at baseline. We have used three very different designs for three different undergraduate classes. Each course included a treatment group, using the SOCR resources, and a control group, using classical instruction techniques. Our findings include marginal effects of the SOCR treatment per individual classes; however, pooling the results across all courses and sections, SOCR effects on the treatment groups were exceptionally robust and significant. Coupling these findings with a clear decrease in the variance of the quantitative examination measures in the treatment groups indicates that employing technology, like SOCR, in a sound pedagogical and scientific manner enhances overall the students' understanding and suggests better long-term knowledge retention.

Central Limit Theorem: New SOCR Applet and Demonstration Activity.

Modern approaches for information technology based blended education utilize a variety of novel instructional, computational and network resources. Such attempts employ technology to deliver integrated, dynamically linked, interactive content and multifaceted learning environments, which may facilitate student comprehension and information retention. In this manuscript, we describe one such innovative effort of using technological tools for improving student motivation and learning of the theory, practice and usability of the Central Limit Theorem (CLT) in probability and statistics courses. Our approach is based on harnessing the computational libraries developed by the Statistics Online Computational Resource (SOCR) to design a new interactive Java applet and a corresponding demonstration activity that illustrate the meaning and the power of the CLT. The CLT applet and activity have clear common goals; to provide graphical representation of the CLT, to improve student intuition, and to empirically validate and establish the limits of the CLT. The SOCR CLT activity consists of four experiments that demonstrate the assumptions, meaning and implications of the CLT and ties these to specific hands-on simulations. We include a number of examples illustrating the theory and applications of the CLT. Both the SOCR CLT applet and activity are freely available online to the community to test, validate and extend (Applet: http://www.socr.ucla.edu/htmls/SOCR_Experiments.html and Activity: http://wiki.stat.ucla.edu/socr/index.php/SOCR_EduMaterials_Activities_GeneralCentralLimitTheorem).