Development of a core outcome set for school-based intervention studies on preventing childhood overweight and obesity: study protocol.

INTRODUCTION: Prevention of childhood overweight is an important health priority. Evidence synthesis from studies evaluating school-based overweight preventive interventions is hampered by the wealth of different outcomes across studies. Therefore, consensus on a core set of outcomes for school-based overweight prevention studies is needed. This paper presents the protocol for the development of a core outcome set (COS) for school-based intervention studies aimed at childhood overweight prevention. METHODS AND ANALYSIS: First, a scoping review will be performed to identify outcomes included in studies evaluating school-based overweight prevention interventions in 6-12 year-old children. Additionally, child focus groups will be organised in three countries to list the outcomes children consider important in school-based interventions. Next, an expert panel will identify all unique outcomes (eg, body composition) from the results of the scoping review and focus groups, ruling out how outcomes were defined and measured (eg, body mass index, body fat). In the next phase, a group of international stakeholders will participate in a Delphi study in which they will rate all unique outcomes on a 9-point Likert scale over three rounds to reach consensus on a COS. Participants will include healthcare professionals, policymakers, teachers, school leaders and parents of 6-12 year-olds. All rated outcomes will be presented to stakeholders in two online consensus meetings. ETHICS AND DISSEMINATION: The Medical Ethics Committee of the VU Medical Center approved the child focus group study in the Netherlands (nr. 2020.071) and the Delphi study-including the consensus meeting (nr. 2022.0295). Other sites will obtain ethics approval for focus groups in their country. The University of Strathclyde School of Psychological Sciences ethics committee approved the Delphi study-including consensus meeting (nr. 72.27.04.2022 .A). The final COS will be disseminated through the diverse networks of all authors and participants. TRIAL REGISTRATION NUMBER: This COS initiative is registered with the Core Outcome Measures in Effectiveness initiative (registration nr. 971).

Cross-validation of cut-points in preschool children using different accelerometer placements and data axes.

The present study cross-validated various cut-points to assess physical activity and sedentary behaviour in preschoolers, using hip- and wrist-worn accelerometers and both vertical axis and vector magnitude data. Secondly, we examined the influence of epoch length on time estimates of physical activity and sedentary behaviour. Sixty-four preschoolers (34 girls) wore two accelerometers, on their right hip and dominant wrist, during 1 hour of free play. Preschoolers' activities were observed by two trained researchers. Area under the curve (AUC) was calculated for the receiving operating characteristic (ROC) curves as a measure of precision. AUC ranges were 0.603-0.723 for sedentary behaviour, 0.472-0.545 for light physical activity and 0.503-0.661 for moderate-to-vigorous physical activity (MVPA), indicating poor to fair precision. Percentage of time classified as sedentary behaviour, light or MVPA according to observation and accelerometer data varied largely between cut-points, accelerometer placements and axes. The influence of epoch length on time estimates was minimal across cut-points, except for one hip-based vector magnitude cut-point. Across all accelerometer placements and data axes, no set of cut-points demonstrated adequate precision for sedentary behaviour, light physical activity and MVPA. The highly variable and omnidirectional activity pattern of preschoolers may explain the lack of adequate cut-points.

Clinical indicators associated with the mode of twin delivery: an analysis of 22,712 twin pairs.

OBJECTIVE: To identify clinical indicators associated with the planned and actual mode of delivery in women with a twin pregnancy. STUDY DESIGN: We performed a retrospective cohort study in women with a twin pregnancy who delivered at a gestational age of 32+0-41+0 weeks and days between 2000 and 2008 in the Netherlands. Data were obtained from a nationwide database. We identified maternal, pregnancy-related, fetal, neonatal and hospital-related indicators that were associated with planned cesarean section (CS) and, for women with planned vaginal delivery (VD), for intrapartum CS. The associations between indicators and mode of delivery were studied with uni- and multivariate logistic regression analyses. RESULTS: We included 22,712 women with a twin pregnancy, of whom 4,310 women (19.0%) had a planned CS. Of the 18,402 women who had a planned VD, 14,034 (76.3%) delivered vaginally, 3,545 (19.3%) had an intrapartum CS, while 823 (4.5%) delivered twin A vaginally and twin B by intrapartum CS. The clinical indicators for a planned CS and an intrapartum CS were comparable: non-cephalic position of both twins (aOR 25.32; 95% CI 22.50-28.50, and aOR 21.94; 95% CI 18.67-25.78, respectively), non-cephalic position of twin A only (aOR 21.67 95% CI 19.12-24.34, and aOR 13.71; 95% CI 11.75-16.00, respectively), previous CS (aOR 3.69; 95% CI 3.12-4.36, and aOR 7.00; 95% CI 5.77-8.49, respectively), nulliparity (aOR 1.51; 95% CI 1.32-1.72, and aOR 4.20; 95% CI 3.67-4.81, respectively), maternal age ≥41 years (aOR 3.00; 95% CI 2.14-4.22, and aOR 2.50; 95% CI 1.75-3.59, respectively), and pre-eclampsia (aOR 2.12; 95% CI 1.83-2.46, and aOR 1.34; 95% CI 1.16-1.56, respectively). CONCLUSION: Both planned and intrapartum CS in twins had comparable predictors: non-cephalic position of both twins or twin A only, previous CS, nulliparity, advanced maternal age, and pre-eclampsia.