Self-reported Anthropometric Tools for Screening Children with Overweight/Obesity Status and A Clustering of Cardiometabolic Risk Factors

Background;The increasing rate of overweight/obesity in children is a serious public health problem worldwide. Childhood obesity has been shown to be associated with a clustering of cardiometabolic risk factors (CMRFs) leading to cardiovascular diseases and diabetes mellitus in later life and premature mortality. Puberty has a complex, entwined relationship with the various CMRFs particularly high body mass index (BMI) and large waist circumference (WC). Self-report method is commonly used for obtaining anthropometric measures and pubertal assessment data because of its simplicity, low cost and non-invasiveness. Self-reported body weight (SRBW) and self-reported body height (SRBH) derived BMI (SRDBMI) and self-reported WC (SRWC) may be useful assessment tools for screening and monitoring the prevalence of overweight/obesity. We assessed the agreement of self-reported Tanner pubertal questionnaire and self-reported Pubertal Development Scale (PDS), SRBW, SRBH and SRWC with measured values. We also examined the diagnostic ability of SRDBMI and SRWC in classifying children with overweight/obesity status and CMRFs clustering. Furthermore, we explored whether consideration of pubertal staging is needed for identifying children/adolescents with a clustering of CMRFs and its moderating effect on predicting cardiometabolic risk by WC or BMI.;Methods;This thesis is composed of two cross-sectional studies and all children/adolescents were recruited from school settings. The first study recruited children/adolescents from a convenience sample aged between 8 and 18 years. The aim of the first study was to assess the agreement of the Tanner pubertal self-reported questionnaire and the self-reported PDS with raters' assessments. Children/adolescents were given Chinese versions of the Tanner pubertal questionnaires, followed by a Chinese PDS to fill out, before undergoing visual depiction physical examination by a same gender rater who was experienced in Tanner staging in a private room. The raters were unaware of the results of the two self-reported questionnaires. The second study recruited children/adolescents, aged between 6 and 18 years using cluster random sampling, from February 2007 to April 2008. A self-administered questionnaire which included questions on demographic data, the two validated self-reported pubertal questionnaires and anthropometric measurements was given to children/adolescents to bring home for completion. Anthropometric measurements, blood pressure (BP) and fasting blood samples for measurements of fasting plasma glucose and lipid profile were taken by trained research staff after the children/adolescents returned the questionnaire on the day of the survey.;Results;Analyses demonstrated good consistency between Tanner self-reported pubertal questionnaire, self-reported PDS, SRBW, SRBH, SRWC and measured values. The SRDBMI and SRWC showed similar diagnostic ability to their measured counterparts to identify children/adolescents with overweight, obesity status and CMRFs clustering. Although no significant association was found between pubertal stages and CMRFs clustering, which may be due to the small numbers of children/adolescents having CMRFs clustering, pubertal stage was found to be significantly associated with individual CMRFs namely large WC, increased triglycerides, and elevated BP in boys and large WC and elevated BP in girls. Pubertal stage has a significant moderator effect on the prediction of CMRFs by WC or BMI.;Conclusion;SRDBMI and SRWC are valuable screening anthropometric tools to identify children/adolescents with overweight/obesity in community settings and public health/epidemiological research in Hong Kong when cost, privacy and other concerns preclude the use of physical assessment. Furthermore, the effect of puberty on the prediction of CMRFs warrants further research into the relationship between puberty, obesity and CMRFs.