BackgroundChildhood obesity is a serious public health concern. School-based interventions hold great promise to combat the rising trend of childhood obesity. This systematic review aimed to assess the overall effects of school-based obesity prevention interventions, and to investigate characteristics of intervention components that are potentially effective for preventing childhood obesity.MethodsWe systematically searched MEDLINE, CENTRAL and Embase databases to identify randomized- or cluster randomized- controlled trials of school-based obesity interventions published between 1990 and 2019. We conducted meta-analyses and subgroup analyses to determine the overall effects of obesity prevention programs and effect differences by various characteristics of intervention components on body mass index (BMI) or BMI Z-score of children.ResultsThis systematic review included a total of 50 trials (reported by 56 publications). Significant differences were found between groups on BMI (− 0.14 kg/m2 (95% confidence interval: − 0.21, − 0.06)) and BMI Z-score (− 0.05 (− 0.10, − 0.01)) for single-component interventions; significant differences were also found between groups on BMI (− 0.32 (− 0.54, − 0.09) kg/m2) and BMI Z-score (− 0.07 (− 0.14, − 0.001)) for multi-component interventions. Subgroup analyses consistently demonstrated that effects of single-component (physical activity) interventions including curricular sessions (− 0.30 (− 0.51, − 0.10) kg/m2 in BMI) were stronger than those without curricular sessions (− 0.04 (− 0.17, 0.09) kg/m2 in BMI); effects of single-component (physical activity) interventions were also strengthened if physical activity sessions emphasized participants’ enjoyment (− 0.19 (− 0.33, − 0.05) kg/m2 in BMI for those emphasizing participants’ enjoyment; − 0.004 (− 0.10, 0.09) kg/m2 in BMI for those not emphasizing participants’ enjoyment). The current body of evidence did not find specific characteristics of intervention components that were consistently associated with improved efficacy for multi-component interventions (P > 0.05).ConclusionsSchool-based interventions are generally effective in reducing excessive weight gain of children. Our findings contribute to increased understandings of potentially effective intervention characteristics for single-component (physical activity) interventions. The impact of combined components on effectiveness of multi-component interventions should be the topic of further research. More high-quality studies are also needed to confirm findings of this review.

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Dentine hypersensitivity (DH) is a common condition that is frequently encountered in dental practice. The aim of this multi-centre and cross-sectional study was to establish the prevalence of DH in the general population in China. A total of 6843 subjects were questioned and examined using a triple syringe with a blast of cold air to confirm the diagnosis of DH. The sensitive surface, loss of attachment and gingival recession of sensitive teeth were measured and recorded. Of the 2932 subjects reporting hypersensitive symptoms, 2363 subjects were further diagnosed as DH, giving an overall prevalence of 34·5%. The greatest number of subjects with DH were within the 50-59 years age group (P < 0·01). The most commonly affected teeth were the premolars and the most provoking factor was the presence of a cold stimulus. The prevalence of DH in a representative sample of the general population in China was 34·5%, indicating that DH is a common oral problem. Therefore, the recognition of the condition and subsequent treatment by the dentist is therefore essential if the condition is to be managed correctly.

Background: To assess the association between plasma retinol-binding protein 4 (RBP4) levels both in the first trimester and second trimester and risk of gestational diabetes mellitus (GDM). Methods: Plasma RBP4 levels and insulin were measured among 135 GDM cases and 135 controls nested within the Peking University Birth Cohort in Tongzhou. Multivariable linear regression analysis was conducted to assess the influence of RBP4 levels on insulin resistance. Conditional logistic regression models were used to compute the odds ratio (OR) and 95% confidence interval (CI) between RBP4 levels and risk of GDM. Results: The GDM cases had significantly higher levels of RBP4 in the first trimester than controls (medians: 18.0 μg/ L vs 14.4 μg/L; P < 0.05). Plasma RBP4 concentrations in the first and second trimester were associated with fasting insulin, homeostasis model assessment for insulin resistance (HOMA-IR), and the quantitative insulin sensitivity check index (QUICKI) in the second trimester (all P < 0.001). With adjustment for diet, physical activity, and other risk factors for GDM, the risk of GDM increased with every 1-log μg/L increment of RBP4 levels, and the OR (95% CI) was 3.12 (1.08-9.04) for RBP4 in the first trimester and 3.38 (1.03-11.08) for RBP4 in the second trimester. Conclusions: Plasma RBP4 levels both in the first trimester and second trimester were dose-dependently associated with increased risk of GDM.

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