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Natalie Woods,1,2 Kristy Wittmeier,1– 3 Kathy Mulder,1 Brenden Dufault,4 Brian Black5,6 1Physiotherapy Department, Health Sciences Centre Winnipeg – Shared Health, Winnipeg, MB, Canada; 2Children’s Hospital Research Institute of Manitoba, Winnipeg, MB, Canada; 3Department of Pediatrics and Child Health, Rady Faculty of Health Sciences, University of Manitoba, Winnipeg, MB, Canada; 4Data Sciences Platform, George & Fay Yee Centre for Healthcare Innovation, Winnipeg, MB, Canada; 5Department of Pediatric Orthopedic Surgery, University of Manitoba, Winnipeg, MB, Canada; 6Child Health Program, Health Sciences Centre Winnipeg – Shared Health, Winnipeg, MB, CanadaCorrespondence: Brian Black, Child Health Program, Health Sciences Centre Winnipeg – Shared Health, 840 Sherbrook Street, Winnipeg, MB, R3A 1S1, Canada, Tel +1-204-787-4204, Fax +1-204-787-2460, Email BBlack@hsc.mb.caPurpose: To evaluate the relationship between body mass index (BMI) and spinal curvature in patients presenting with idiopathic scoliosis at a major pediatric tertiary care centre.Patients and Methods: Retrospective chart review (2015– 2019). Data extracted from patient’s first visit included age, sex, height, weight, spinal curvature (magnitude, location), referral source, physical activity participation (yes/no), pain (yes/no). Demographics were analyzed descriptively. The relationship between BMI and spinal curve magnitude was analyzed using Spearman correlation coefficient. Linear regression was applied to determine the relationship between BMI, curve magnitude, and curve location. Exploratory univariate analyses were conducted for BMI and referral source, pain, and skeletal maturity, and physical activity and pain.Results: A total of 206 patient charts were included (177 females, 29 males). Patients presented with double major (41.3%), thoracic (26.7%), thoracolumbar (22.8%), and lumbar (9.2%) curves. Mean (SD) BMI percentile was 48.3 (30.5). No relationship existed between BMI percentile and curve magnitude with curve locations combined. However, a test for interaction revealed a positive relationship between BMI percentile and curve magnitude for adolescents with double major curves, and a negative relationship for adolescents with thoracic curves. Exploratory analyses suggested a relationship between BMI percentile and presence of pain, and between referral source and curve magnitude. No relationship was observed between BMI and skeletal maturity, or physical activity and pain.Conclusion: The relationship between BMI varied by curve location within this cohort, in which most patients presented with a BMI < 85th percentile. Findings highlight the importance of sensitive history taking and careful physical examination for early detection of scoliosis.Keywords: scoliosis, body mass index, curve magnitude, screening, chart review

The Earth's surface volcanism exerts first-order controls on the composition of the atmosphere and the climate. On Earth, the majority of surface volcanism occurs at mid-ocean ridges. In this study, based on the dependence of melt fraction on temperature, pressure, and composition, we compute melt production and degassing rate at mid-ocean ridges from three-dimensional global mantle convection models with plate motion history as the surface velocity boundary condition. By incorporating melting in global mantle convection models, we connect deep mantle convection to surface volcanism, with deep and shallow mantle processes internally consistent. We compare two methods to compute melt production: a tracer method and an Eulerian method. Our results show that melt production at mid-ocean ridges is mainly controlled by surface plate motion history, and that changes in plate tectonic motion, including plate reorganizations, may lead to significant deviation of melt production from the expected scaling with seafloor production rate. We also find a good correlation between melt production and degassing rate beneath mid-ocean ridges. The calculated global melt production and CO2 degassing rate at mid-ocean ridges varies by as much as a factor of 3 over the past 200 Myr. We show that mid-ocean ridge melt production and degassing rate would be much larger in the Cretaceous, and reached maximum values at ∼150–120 Ma. Our results raise the possibility that warmer climate in the Cretaceous could be due in part to high magmatic productivity and correspondingly high outgassing rates at mid-ocean ridges during that time.