National Nutrition and Health Systematic Survey for Children 0-17 Years of Age in China / 生物医学与环境科学（英文）

The main purpose of the National Nutrition and Health Systematic Survey for children 0-17 years of age in China (CNHSC) was to collect basic data on the nutrition, development, and health status for children in different regions across China using evidence-based, reliable, and cost-effective approaches. Children and their parents or guardians from seven regions (south, southwest, north, northwest, eastern, central, and northeast China) in China were recruited. A multi-stage stratified randomized sampling method was used. Two provinces were randomly sampled from each of the seven regions, from which one urban district and one rural country were also randomly sampled, resulting in a total of 28 survey counties/districts. Dietary surveys, health examinations, laboratory testing, and questionnaires were used to collect dietary intake, nutritional status, child development, and health status information. Nutrition, health, and lifestyle assessment of children and their parents was determined using the Knowledge Attitude Practice (KAP) survey. Greater than 100,000 children (38,000 children < 6 years of age and 66,000 children 6-17 years of age) completed the survey. The survey provided comprehensive data on child nutrition and health status for future studies and will serve as the basis for an integrated nutrition and health improvement strategies proposal for children in China.

Changes in Waist Circumference and Abdominal Obesity among Chinese Adults over a Ten-year Period / 生物医学与环境科学（英文）

<p><b>OBJECTIVE</b>The aim of this study was to describe changes in waist circumference (WC) and prevalence of abdominal obesity over a period of 10 years among Chinese adults in different socio-economic status (SES).</p><p><b>METHODS</b>Data derived from the China Nutrition and Health Surveillance during 2002 and 2010-2012. We calculated the mean WC and the prevalence of abdominal obesity by gender, place of residence, SES indicators (education, income, and marital status), and body mass index (BMI) categoriesand used pooled t-tests to assess the differences between the two time periods.</p><p><b>RESULTS</b>26.0% of men and 25.3% of women had abdominal obesity in 2010-2012. The age-adjusted mean WC increased by 2.7 cm among men and 2.1 cm among women; the age-adjusted prevalence of abdominal obesity increased by 7.7% among men and 5.3% among women. The rising trends were observed in all subgroups except for a negative growth in high-income women. People living in rural areas with low education and income and with a BMI of 18.5 to 23.9 kg/m2 had a greater absolute and relative increase in WC. People living in rural areas with low income had a greater relative increase in abdominal obesity.</p><p><b>CONCLUSION</b>The mean WC and prevalence of abdominal obesity among Chinese adults have increased during the past 10 years. Gender differences were noted using various SES indicators.</p>

Comparison of Undernutrition Prevalence of Children under 5 Years in China between 2002 and 2013 / 生物医学与环境科学（英文）

<p><b>OBJECTIVE</b>To describe the undernutrition status of children under 5-year in China, and study the trend between 2002 and 2013).</p><p><b>METHODS</b>The study was based on two national surveys. Undernutrition was determined against WHO's 2006 growth standards. The prevalence in 2013 and 2002 was weighted by China sixth National Population Census (2010). The relationship between undernutrition and gender/age groups/different areas use weighted logistic regression.</p><p><b>RESULTS</b>The results indicated the overall prevalence of stunting, underweight, and wasting of Chinese children under 5-year was 8.1%, 2.4%, and 1.9% in 2013, respectively. The prevalence of stunting was higher for children aged 12-47 month, while underweight was higher for children aged 48-59 month. The prevalence of undernutrition was higher in rural areas than in urban areas, especially in poor rural areas. There was a decline of stunting, underweight, and wasting between 2002 and 2013 among the children, with greater reduction in rural areas than in urban areas.</p><p><b>CONCLUSION</b>The prevalence of undernutrition of children under 5-year remains high in rural areas especially in poor rural areas in China. It is urgent to take action to control undernutrition in the vulnerable areas and subgroups.</p>

Report on childhood obesity in China (10): association of sleep duration with obesity / 生物医学与环境科学（英文）

<p><b>OBJECTIVES</b>To explore the association of sleep duration with obesity among children in urban areas of China.</p><p><b>METHODS</b>A total of 6 576 children (3 293 boys and 3 283 girls) aged 7-11 years were randomly selected from 36 primary schools in 6 metropolitan cities in China. A 7-day Physical Activity Recall was used to assess the sleep duration and physical activity level. The height, weight, waist circumference (WC) and percentage of body fat (%BF, as determined by bioelectrical impedance analysis technique) were measured by following the standardized operation procedures. The information on demography, lifestyle and eating habits was collected with a self-administered questionnaire from participants and their parents.</p><p><b>RESULTS</b>The average sleep duration per night in the children was 9.7 h with the decreasing trends along with the increase of age (P < 0.05). The sleep duration was negatively associated with body mass index (BMI) and WC in both boys and girls after adjustment for confounders (beta value -0.23 and -0.82 for boys, -0.24 and -0.91 for girls, respectively, P < 0.01). However, no significant association of sleep duration with %BF was found. Children who slept less than 9.0 h per night had a higher risk for overweight and obesity (OR = 1.29, 95% CI: 1.01, 1.64) and abdominal obesity (OR=1.38, 95% CI: 1.04, 1.83) as compared with those who slept for 10.0-10.9 h.</p><p><b>CONCLUSIONS</b>Short sleep duration is associated with obesity. It is important to ensure adequate sleep duration of children and foster their healthy lifestyle at an early stage of life.</p>

Waist circumference reference values for screening cardiovascular risk factors in Chinese children and adolescents / 生物医学与环境科学（英文）

<p><b>OBJECTIVES</b>To explore the optimal threshold values of waist circumference (WC) for detecting cardiovascular (CV) risk factors among Chinese children and adolescents.</p><p><b>METHODS</b>Association of WC with CV risk factors was studied among 65,898 children aged 7-18 years whose data were pooled from nine previous studies in China. CV risk factors in this study included hypertension (blood pressure above 95 percentile levels), dyslipidemia (with one or more of the following three indexes: TG > or = 1.7 mmol/L, TC > or = 5.18 mmol/L, and HDL-C < or = 1.04 mmol/L) and elevated glucose level (fasting plasma glucose > or = 5.6 mmol/L). Receive-operating characteristic analysis (ROC) and logistic regression were employed to derive optimal age- and sex-specific waist circumference references for predicting CV risk factors.</p><p><b>RESULTS</b>A slight increasing trend of CV risk factors was observed starting from the 75th percentile of waist circumference in the study population, while a remarkable increasing trend occurred from the 90th percentile. The optimal waist circumference thresholds for predicting high blood pressures were at the 75th percentile for both boys and girls, which was at the 90th percentiles for detecting at least two of the above three CV risk factors. In comparison with children with waist circumference below the 75th percentile, the odds ratio of two CV risk factors doubled among children with waist circumference between the 75th and the 90th percentile, and increased by 6 times among children with waist circumference above the 90th percentile. The trend of high blood pressure increasing with waist circumference remained significant after having been stratified by BMI category.</p><p><b>CONCLUSION</b>The 75th and the 90th percentiles of WC are the optimal cut-off points for predicting an increased and a substantially increased risk of CV factors in Chinese children and adolescents, respectively.</p>

Relationship of body mass index, waist circumference and cardiovascular risk factors in Chinese adult / 生物医学与环境科学（英文）

<p><b>OBJECTIVE</b>To compare the relative risk of waist circumference (WC) and/or BMI on cardiovascular risk factors.</p><p><b>METHODS</b>A cross-sectional data of 41 087 adults (19 567 male and 21 520 female) from the 2002 China National Nutrition and Health Survey were examined. According to the obesity definition of WGOC (BMI, 24 kg/m2 and 28 kg/m2; WC, male 85 cm and 95 cm for male, 80 cm and 90 cm for female), the study population were divided into 9 groups. The prevalence and odds ratio (ORs) of cardiovascular disease (CVD) risk factors (hypertension, high fasting plasma glucose and dyslipidemia) were compared among these 9 groups. Stepwise linear regression analyses were used to compare the likelihood of BMI and/or WC on CVD risk factors. RESULTS Both the indexes levels and the odds ratios of CVD risk factors were significantly increased (decreased for HDL-C levels) along with the increase of WC and/or BMI, even when the effect of age, sex, income, education, sedentary activity and dietary factors were adjusted. The variances (R2) in CVD risk factors explained by WC only and BMI only were quite similar, but a little bit larger when WC and BMI were combined. The standard beta was higher of BMI when predicting systolic BP and was higher of WC when predicting TG TC and HDL.</p><p><b>CONCLUSIONS</b>BMI and WC had independent effects on CVD risk factors and combination of BMI and WC would be more predictive. Findings from the present study provided substantive evidence for the WGOC recommendation of a combined use of BMI and WC classifications.</p>

Waist circumference reference values for screening cardiovascular risk factors in Chinese children and adolescents aged 7-18 years / 中华流行病学杂志

Objective To explore the optimal threshold values of waist circumference (WC) in detecting the risk on cardiovascular (CV) among the Chinese children and adolescents. Methods Association of WC and CV risk factors were studied among 65 898 children and adolescents aged 7-18 years whose data were pooled from nine studies carried out in China. Receive-operating characteristic analysis (ROC) and logistic regression were employed to derive optimal age- and sex-specific waist circumference references for predicting the CV risk factors. Results A slight increasing trend of CV risk factors was observed starting from the 75th percentile of waist circumference in the study population, while a remarkable increasing trend occurred from the 90th percentile. The optimal waist circumference thresholds for predicting high blood pressures were at the 75th percentile for both boys and girls, and at the 90th percentiles it could detect at least two of the above three CV risk factors. In comparison with children whose waist circumference was below the 75th percentile, the odds ratio of two CV risk factors doubled among children with waist circumference between 75th and 90th percentile, and increased by 6 times among children with waist circumference above the 90th percentile. The trend of high blood pressure increasing remained significant with waist circumference after having been stratified by BMI category. Conclusion The 75th and the 90th percentile of WC appeared to be the optimal cut-off points for predicting an increased and a substantially increased risk of CV factors in Chinese children and adolescents.

Odds ratio on cardiovascular risk factors of obesity defined by waist and body mass index / 中华流行病学杂志

Objective To compare the odds ratio of waist circumference (WC) and/or body mass index (BMI) on cardiovascular risk factors. Methods Data on a cross-sectional study involving 41 087 adults (19 567 male, 21 520 female) from the 2002 China National Nutrition and Health Survey were examined. According to the obesity definition of the Chinese Working Group on Obesity for Children (WGOC) (BMI, 24 and 28 kg/m2; WC, male 85 cm, female 80 cm), the study population were divided into 9 groups. The prevalence and odds ratio (OR) of cardiovascular disease (CVD) risk factors were compared among these 9 groups. Variation and standard β were indexes being used to compare the likelihood of BMI and/or WC on CVD risk factors. Results Within each of the BMI categories, with few exceptions, indices levels on CVD risk factors were significantly increased (decreased for HDL-C levels) with the increase of WC, and vice versa. After adjusting the effects of age, sex, income, education, sedentary activity and dietary factors, the ORs of hypertension in adults with higher WC within each of the BMI categories were higher than adults with lower WC, and the ORs of hypertension in adults with higher BMI within each of the WC categories were higher than adults with lower BMI. Similar trends were found for high fast plasma glucose (FPG) and dyslipidemia. The variation in CVD risk factors explained only by WC and BMI were quite similar,but slightly larger when combined WC with BMI. Standard β was higher on BMI when predicting systolic BP and was higher on WC when predicting TG, TC and HDL-C. Conclusion BMI and WC were independently associated with the risk factors on CVD.To combine the BMI and WC, the results could accurately evaluate the risk of CVD, thus to provide substantive evidence that the WGOC cutoff points for the WC might help in identifying those population under increased risk.