Drinking in different periods of a day of primary and middle school students in four cities of China / 中华预防医学杂志

<p><b>OBJECTIVE</b>To investigate intake of water in different periods of a day of primary and middle school students in Beijing, Shanghai, Guangzhou and Chengdu of China.</p><p><b>METHODS</b>A total of 5914 primary and middle school students from Beijing, Shanghai, Guangzhou and Chengdu were recruited using multiple-stage random sampling method from September to October 2011. Among them, 5868 students completed the survey. The information of amounts and types of drinking in 8 time periods, morning, afternoon, night as well as in meal and non-meal time in 24 hours of a day was recorded by subjects for seven consecutive days using a quantitative measurement. This information was analyzed by different periods.</p><p><b>RESULTS</b>The amount of drinking water among 8 periods of a day was (99 ± 101), (130 ± 106), (191 ± 155), (96 ± 107), (246 ± 172), (90 ± 101), (188 ± 135) and (50 ± 81) ml, respectively for before breakfast, during breakfast, after breakfast, during lunch, after lunch, during dinner, after dinner, and midnight (F = 1679.77, P < 0.01). Based on three periods of a day, the amount of drinking water in the morning (420 ± 242) ml was the statistically significantly most, followed by afternoon (341 ± 199) ml, and the least in the evening (327 ± 195) ml (F = 325.23, P < 0.01). The distribution trend of plain water in three periods was the same as total drinking water, with (270 ± 209), (250 ± 179) and (224 ± 177) ml, respectively (F = 84.89, P < 0.01) ; but beverage consumption was the most in the morning(151 ± 133) ml, then in the evening (103 ± 122) ml, and the least in the afternoon (91 ± 199) ml (F = 373.56, P < 0.01). The daily plain water consumption in meal time was (316 ± 247) ml, while it in non-meal time was (773 ± 445) ml with statistically significant difference (Z = 65.2, P < 0.01). There was no significant difference in meal time between plain water (165 ± 194) ml and beverage (151 ± 152) ml (Z = 0.59, P = 0.56) whilst plain water (579 ± 408) ml in non-meal time was significantly higher than beverages (194 ± 204) ml (Z = 64.5, P < 0.01).</p><p><b>CONCLUSION</b>The amount of drinking water of primary and middle school students in different periods of a day was different in four cities of China.</p>

Water intake of primary and middle school students in four cities of China / 中华预防医学杂志

<p><b>OBJECTIVE</b>To investigate total intake of drinking water of primary and middle school students in four cities of China, and to provide scientific evidence for developing standard of intake of drinking water for primary and middle school students in China.</p><p><b>METHODS</b>A total of 5914 primary and middle school students were selected from Beijing, Shanghai, Chengdu and Guangzhou using multi-stage random sampling method and 5868 subjects completed the survey. The information on the amounts of daily drinking water was recorded for seven consecutive days using a 24 hour measurement. The amounts of daily drinking water among different cities and ages and between boys and girls or urban and rural were analyzed.</p><p><b>RESULTS</b>The average daily total drinking water of subjects was (1089 ± 540) ml, with significant differences among the four cities ((1165 ± 549), (1126 ± 544), (866 ± 421), (1185 ± 568) ml in Beijing, Shanghai, Chengdu and Guangzhou, respectively; F = 114.28, P < 0.05). The average daily drinking water was significantly higher in boys (1157 ± 575) ml than in girls (1026 ± 498) ml (Z = 8.88, P < 0.05), and in urban (1185 ± 578) ml than in rural (991 ± 480) ml (Z = 13.94, P < 0.05). The difference among different ages was statistically significant (F = 91.53, P < 0.05) with ascending order in 7 - 10, 11 - 13 and 14 - 17 years old ((953 ± 483), (1134 ± 551) and (1170 ± 557) ml respectively).</p><p><b>CONCLUSION</b>The daily consumption of total drinking water is different in primary and middle school students among different cities, regions, genders and ages.</p>

The relationship between within-day drinking occasion and intake amount of water of primary and middle school students in four cities of China / 中华预防医学杂志

<p><b>OBJECTIVE</b>To investigate the number of drinking occasions per day and average amount consumed per drinking occasion of primary and middle school students in four cities of China, and understand the relationship among drinking occasion, average amount consumed per drinking occasion and total drinking water.</p><p><b>METHODS</b>A total of 5914 primary and middle school students from Beijing, Shanghai, Guangzhou and Chengdu were selected using multiple-stage random sampling method, and 5868 students completed the study from September to October in 2011. The detailed information of amounts and types of daily drinking water was recorded by subjects using a 24 hours measurement for seven consecutive days. Analysis of the relationship among drinking occasion, average amount consumed per drinking occasion and total drinking water was carried out.</p><p><b>RESULTS</b>The daily total drinking water of subjects was (1089 ± 540) ml; the daily number of drinking occasions was (4.7 ± 1.8) times, with 79.1% (4639/5868) of subjects reporting 6 or less drinking occasions. The amount consumed per drinking occasion was (239 ± 96) ml, plain water (231 ± 112) ml, and beverages (237 ± 112) ml. The number of drinking occasions of subjects was positively correlated with total drinking water (r = 0.614, P < 0.05), and negatively correlated with the average amount consumed per drinking occasion (r = -0.211, P < 0.05). Total drinking water and the average amount consumed per drinking occasion was positively correlated (r = 0.598, P < 0.05).</p><p><b>CONCLUSION</b>The number of drinking occasion of primary and middle school students more than 6 times was fewer in four cities of China, but the average amount of beverages consumed per drinking occasion was relatively more. With the increasing of drinking occasion, the average amount consumed per drinking occasion decreased, but total drinking water increased.</p>

Daily intake of plain water and beverages of primary and middle school students in four cities of China / 中华预防医学杂志

<p><b>OBJECTIVE</b>To describe the daily consumption of plain water and beverages of primary and middle school students in four cities of China.</p><p><b>METHODS</b>A total of 5914 students from Beijing, Shanghai, Guangzhou and Chengdu were selected using multiple-stage random sampling method, and 5868 students completed the study from September to October 2011. The information on amounts and types of drinking water was recorded using a 24 hour measurement for seven consecutive days. The amount of plain water and beverages was analyzed for subjects in different gender, grades and cities.</p><p><b>RESULTS</b>The daily consumption of plain water of subjects was (744 ± 484) ml (68.3% of total drinking water) with statistically significant difference among the Guangzhou, Beijing, Shanghai and Chengdu ((869 ± 528), (818 ± 518), (702 ± 471), and (573 ± 333) ml; F = 113.74, P < 0.05). The amount of plain water in boys (809 ± 534) ml was significantly higher than in girls (683 ± 436) ml (Z = 9.58, P < 0.05) while higher in urban (792 ± 531) ml than in rural (695 ± 427) ml (Z = -6.09, P < 0.05). The consumption of plain water in high school students was the highest (829 ± 513) ml, and that in primary students was the lowest (672 ± 426) ml (F = 55.23, P < 0.05). The average daily consumption of beverages was (345 ± 287) ml (31.7% of total drinking water) and the highest in Shanghai (424 ± 304) ml, then in Beijing (347 ± 303) ml and in Guangzhou (316 ± 267) ml, the lowest in Chengdu (293 ± 255) ml (F = 58.94, P < 0.05). The consumption of beverages for students in urban areas (394 ± 301) ml was higher than that in rural areas (296 ± 264) ml (Z = -14.48, P < 0.05), but no significant difference between boys (348 ± 306) ml and girls (342 ± 269) ml (Z = -1.44, P > 0.05). The consumption of beverages of high school students (356 ± 309) ml and middle school students (360 ± 301) ml were higher than primary school students (328 ± 263) ml (F = 8.37, P < 0.05).</p><p><b>CONCLUSION</b>The major drinking water of primary and middle school students in four cities of China was plain water. The amounts of consumption of plain water and beverages varied in different cities, urban and rural and levels of education.</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>

Report on childhood obesity in China (9): sugar-sweetened beverages consumption and obesity / 生物医学与环境科学（英文）

<p><b>OBJECTIVE</b>To explore the associations between sugar-sweetened beverage (SSB) consumption and obesity as well as obesity-related cardiometabolic disorders among children in China.</p><p><b>METHODS</b>A total of 6974 (boys 3558, girls 3412) children aged 6-13 years participated in the study. Each participant's height, weight, waist circumference, fasting glucose, triglycerides, total cholesterol, high-density lipoprotein cholesterol, and low-density lipoprotein cholesterol were measured. The type of beverage consumption was determined using a self-administered questionnaire.</p><p><b>RESULTS</b>SSBs were consumed regularly by 46.1% of the children. The prevalence [adjusted odds ratio (95% confidence internal (CI)] of obesity was 7.6% [as the reference group (ref.)], 10.1% [1.36(1.07, 1.74)], and 11.6% [1.46(1.21, 1.75)], among children who regularly drank milk, other beverages and SSBs, respectively. Regularly drinking SSBs elevated the likelihood of abdominal obesity [adjusted odds ratio (95% CI): 1.36 (1.17, 1.59)]. The prevalence [adjusted odds ratio (95% CI)] of obesity among children who regularly drank sports/caloric beverages, carbonated beverages, sweet tea, and plant protein beverages was 16.8% [2.00(1.31, 3.07)], 12.7% [1.52(1.23, 1.88)], 11.5% [1.52(1.18, 1.95)], and 10.4% [1.41(1.03, 1.94)], respectively, which was higher than that of regular milk drinkers [7.6 % (ref.)]. The prevalence [adjusted odds ratio (95% CI)] of abdominal obesity among children who regularly drank sweet tea, fruit/vegetable juices, and carbonated beverages was 17.7% [1.55(1.26, 1.90)], 16.2% [1.36(1.09, 1.70)], and 15.3% [1.24(1.03, 1.50)], respectively, which was much higher than that of regular milk drinkers [12.8% (ref.)].</p><p><b>CONCLUSIONS</b>Regular SSB consumption was positively related to obesity and abdominal obesity. This relationship should be investigated further using a longitudinal study design.</p>

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.

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.

Report on childhood obesity in China (8): effects and sustainability of physical activity intervention on body composition of Chinese youth / 生物医学与环境科学（英文）

<p><b>OBJECTIVES</b>To determine whether a large-scale physical activity intervention could affect body composition in primary school students in Beijing, China.</p><p><b>METHODS</b>The study design was one-year cluster randomized controlled trial of physical activity intervention (20 min of daily exercise in the classroom) with an additional year of follow-up among 4 700 students aged 8-11 years at baseline.</p><p><b>RESULTS</b>After the one-year intervention, BMI increased by 0.56 kg/m(2) (SD 1.15) in the intervention group and by 0.72 kg/m(2) (SD 1.20) in the control group, with a mean difference of -0.15 kg/m(2) (95% CI: -0.28 to -0.02). BMI z score decreased by -0.05 (SD 0.44) in the intervention group, but increased by 0.01 (SD 0.46) in the control group, with a mean difference of -0.07 (-0.13 to -0.01). After another year of follow up, compared to the control group, children in the intervention group had significantly lower BMI (-0.13, -0.25 to -0.01), BMI z score (-0.05, -0.10 to -0.01), fat mass (-0.27 kg, -0.53 to -0.02) and percent body fat (-0.53, -1.00 to -0.05). The intervention had a more pronounced effect on weight, height, BMI, BMI z score, and body composition among obese children than among normal weight or overweight children. Compared to the control group, the intervention group had a significantly higher percentage of children who maintained or reduced their BMI z score at year 1 (P=0.008) and year 2 (P=0.04).</p><p><b>CONCLUSIONS</b>These findings suggest that 20 min of daily moderate to vigorous physical activity during the school year is a feasible and effective way to prevent excessive gain of body weight, BMI, and body fatness in primary school students.</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>