RESUMEN
CONTEXT: Childhood and adolescence are critical periods for lifelong bone health. The impact of obesity on these phases is controversial, which may be due to the lack of standards for age-, sex-, and puberty-specific Bone turnover markers (BTMs) which could sensitively reflect bone metabolism. OBJECTIVE: To generate age-, sex, and puberty stage-specific BTMs reference curves in children and adolescents and to explore the effect of obesity on bone metabolism in the Chinese population. METHODS: Our study was part of the Evaluation and Monitoring on School-based Nutrition and Growth in Shenzhen study. 800 participants aged 6â¼18 years with normal body mass index (BMI) were selected to establish BTM reference curves for boys and girls at different ages under different pubertal development stages. Additionally, 200 participants with obesity (BMI >P95th) were matched with healthy children from the original cohort at a 1:1 ratio. All participants underwent bone mineral density assessment, and serum levels of P1NP and ß-CTX were measured. RESULTS: The BTMs values presented significant age, sex, and puberty stage differences. Analysis of serum BTMs based on the established reference revealed a higher percentage of low-level P1NP in boys with obesity (P=0.005); no significant difference was observed in girls. However, the obese group showed a significantly higher proportion of high ß-CTX levels for girls, not boys (P=0.022). CONCLUSIONS: We provide age-, sex-, and puberty stage-specific P1NP and ß-CTX reference curve. According to these, obesity appeared to be a negative factor for bone formation in boys and for bone resorption in girls.
RESUMEN
BACKGROUND: Shenzhen has made great efforts to address the tobacco epidemic in the past decade. This study aims to evaluate the current status of the tobacco epidemic among adolescent in Shenzhen, China. METHODS: The multi-stage random cluster sampling method was used in the school-based cross-sectional study in 2019 and a total of 7,423 junior and high school (both senior and vocational) students were recruited. Information on cigarette use was collected by the electronic questionnaire. Logistic regression analysis was used to examine the associations between current cigarette use and associated factors. ORs with their 95% CIs were reported. RESULTS: The prevalence of current cigarette use among adolescents was 2.3%, with boys (3.4%) significantly higher than girls (1.0%). Smoking rates in junior high schools, senior high schools, and vocational senior high schools were 1.0%, 2.7%, and 4.1%, respectively. The results of multivariate logistic regression analysis indicated that gender, age, parental smoking, teachers smoking in schools, friends smoking, exposure to tobacco marketing, and misconceptions about cigarette use were associated factors for adolescent smoking behaviour. CONCLUSIONS: The prevalence of current smoking was relatively low among adolescent in Shenzhen, China. Personal characteristics, family, and school were associated with current adolescent smokers.
