Dairy Consumption and Associations with Nutritional Status of Chinese Children and Adolescents / 生物医学与环境科学（英文）

OBJECTIVE@#This study aimed to describe frequency and quantity of total dairy consumption of Chinese children and adolescents and explore the associations between dairy consumption and nutrition status, including stunting, wasting, overweight, and obesity.@*METHODS@#Participants included 28,250 children and adolescents aged 6-17 years old. A food frequency questionnaire (FFQ) including 100 kinds of food was used to collect information about frequency and quantity of dairy consumption. Determination of stunting was with a height cutoff value for age and gender, and determination for wasting, overweight, and obesity was with BMI for age and gender.@*RESULTS@#Of the total sample, 36.1% of children aged 6-17 reported consuming dairy food more than once per day (⪖ 1/day). The average total dairy intake of all the participants was 126.7 g/day. For boys, dairy consumption had an inverse correlation with stunting and wasting after controlling for confounders. For girls, dairy consumption was negatively associated with stunting and obesity after controlling for confounders as above.@*CONCLUSION@#Dairy consumption in Chinese children and adolescents was relatively lower than that in developed countries, and was negatively associated with stunting and wasting for boys and with stunting and obesity for girls.

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 (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>

Food water sources analysis of adults in four cities of China in summer / 中华预防医学杂志

<p><b>OBJECTIVE</b>To investigate the food water sources of adults in the four cities of China in summer.</p><p><b>METHODS</b>A total of 64 adults aged 18 - 60 yrs from four cities (Beijing, Shanghai, Chengdu and Guangzhou)were selected using convenient sampling method. The food samples were collected by using duplicate portion method and the water content of food samples were determined by using the national standard. The information on amounts and types of daily drinking soup was recorded by subjects using a quantitative measurement.</p><p><b>RESULTS</b>A total of 63 subjects had completed the investigation. The median of daily water from food of subjects was 1157 ml, while water from staple food was 480 ml, the median ratio of which accounting for 41.8% of water from food. Water from dishes was 427 ml, the median ratio of which accounting for 37.9% of water from food. Water from soups was 133 ml, the median ratio of which accounting for 13.8% of water from food. Water from snacks was 0 ml, the median ratio of which accounting for 6.4% of water from food. The medians of water from staple food (384, 388 and 435 ml, respectively) in Beijing, Shanghai and Guangzhou was significant lower than that of Chengdu subjects' (900 ml, χ(2) = 21.27, P = 0.000). But the median proportion of water from staple food of subjects in Beijing (47.7%) was significantly higher than that in Chengdu (43.2%), Shanghai (42.9%) and Guangzhou (33.9%) (χ(2) = 8.69, P = 0.034). The median of amount and proportion of water from soups of subjects in Guangzhou (267 ml, 24.4%) and Chengdu(278 ml, 15.7%) was significantly higher than that in Shanghai (133 ml, 9.0%) and Beijing (100 ml, 5.8%) (amount: χ(2) = 22.52, P = 0.000;proportion: χ(2) = 16.27, P = 0.001).</p><p><b>CONCLUSION</b>The staple food and dishes are the main sources of daily food water.</p>

Water intake sources analysis of adults in four cities of China in summer / 中华预防医学杂志

<p><b>OBJECTIVE</b>To investigate the water intake sources of adults in the four cities of China in summer.</p><p><b>METHODS</b>A total of 64 adults aged 18 - 60 yrs from the four cities (Beijing, Shanghai, Chengdu and Guangzhou) were selected using convenient sampling method. The information on amounts and types of daily drinking water was recorded by subjects for three consecutive days using a quantitative measurement. The food samples were collected by using duplicate portion method and the water content of food samples were determined.</p><p><b>RESULTS</b>The median of daily total water intake of 63 subjects was 3045 ml, while daily total drinking water was 1600 ml, the median ratio of which accounting for 55.8% of total water intake. Water from food was 1157 ml, the median ratio of which accounting for 41.4% of total water intake. The median of daily total water intake (3566 ml) and the ratio of water from food (55.3%) of subjects in Chengdu was significantly higher than subjects in Guangzhou (2929 ml, 45.4%), Shanghai (2748 ml, 33.1%) and Beijing (2743 ml, 31.3%) (daily total water intake: χ² = 10.42, P = 0.015;the proportion of water: χ² = 28.48, P < 0.01). Daily total water intake in men (3302 ml) was significantly higher than that in women (2900 ml) (Z = 2.35, P = 0.019).</p><p><b>CONCLUSION</b>Daily total water intake of subjects in summer was more than the current Chinese recommended total water intake (2200 ml), with the main part of drinking water and water from food.</p>

Knowledge on drinking water of adults in four cities of China / 中华预防医学杂志

<p><b>OBJECTIVE</b>To understand the status on knowledge of drinking water among adults aged 18 - 60 yrs in Beijing, Shanghai, Chengdu and Guangzhou of China.</p><p><b>METHODS</b>A total of 1483 adults aged 18 - 60 yrs from the four cities (Beijing, Shanghai, Chengdu and Guangzhou) were selected using multiple-stage random sampling method. The information was collected by face-to-face interview. Through face to face interview, investigators surveyed the daily water intake, the harm of dehydration, time of drinking water and healthy drinks knowledge using a questionnaire. Knowledge awareness was compared through χ(2) test for different cities, urban and rural, genders.</p><p><b>RESULTS</b>The unawareness rate of minimum drinking water volume (1200 ml/d) was 28.4% (421/1483). The rate in Chengdu was the highest (41.8%, 156/373). The rate in women (32.4%, 241/745) was significantly higher than that in men (24.4%, 180/738) (χ(2) = 11.55, P < 0.01). The unawareness rate of the harm of dehydration was 14.4% (213/1483). The rate in Chengdu (18.5%, 69/373) and Guangzhou (18.3%, 68/371) was higher than that in the other cities. The rate in rural (18.6%, 137/736) was significantly higher than that in urban (10.2%, 76/747) (χ(2) = 21.47, P < 0.01). The people who considered drinking water when they felt thirsty as healthy behavior accounted for 48.3% (716/1483). The rate in Chengdu was the highest (59.0%, 220/373). The unawareness rate of plain water being the best accounted for 18.9% (280/1483), while 17.9% (50/280) of them considered beverages as the best.</p><p><b>CONCLUSIONS</b>The knowledge of drinking water among 18 - 60 yrs residents in the four cities is not comprehensive. We should enhance propaganda of healthy drinking water.</p>

Water intake of adults in four cities of China in summer / 中华预防医学杂志

<p><b>OBJECTIVES</b>To investigate total drinking water intake of adults in the four cities of China in summer.</p><p><b>METHODS</b>A total of 1483 adults aged 18 - 60 yrs from Beijing, Shanghai, Chengdu and Guangzhou were selected using multiple-stage random sampling method. The information of amounts and types of daily drinking water was recorded by subjects for seven consecutive days using a quantitative measurement. The amounts and types of daily drinking water among different cities and between men and women or urban and rural was analyzed.</p><p><b>RESULTS</b>The median of daily total drinking water of subjects was 1488 ml, with significant difference among the four cities (1579, 1793, 1150, 1467 ml in Beijing, Shanghai, Chengdu and Guangzhou city, respectively, χ(2) = 154.31, P = 0.000). The median of daily drinking water was significantly higher in men (1679 ml) than women (1370 ml) (Z = 8.34, P = 0.000), but no significant difference was found between urban (1514 ml) and rural (1466 ml) daily drinking water median (Z = -0.81, P = 0.420). The median of daily consumption of plain water, tea and beverages were 786, 109, 186 ml, respectively. Among four cities, the highest consumption of plain water was in subjects of Guangzhou (917 ml), while the highest tea consumption in Shanghai (257 ml) and the highest beverages consumption in Shanghai (323 ml) and Beijing (264 ml). Consumption of tea in men (229 ml) was significantly higher than that in women (57 ml) (Z = 7.52, P = 0.000). Subjects in urban (693 ml) had lower consumption of plain water than those in rural (914 ml). The proportion was 32.4% (480/1483) for subjects with water drinking less than 1200 ml per day.</p><p><b>CONCLUSION</b>The daily consumption of total drinking water, including plain water, tea and beverages is different in adults among different cities and is different in gender and regions. It is nearly 1/3 of subjects with daily total drinking water less than current Chinese recommended water intake (1200 ml).</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.

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.

The association between vitamin D and bone mineral density of urban postmenopausal women in Beijing / 中华预防医学杂志

<p><b>OBJECTIVE</b>To study the association between vitamin D status and bone mineral density(BMD) in urban postmenopausal women in Beijing.</p><p><b>METHODS</b>A total of 400 community-dwelling women older than 60 (median age 67.8 years) were selected randomly from 17 community of 3 districts in Beijing by cluster sampling method from May to July, 2008. Serum 25(OH)D concentrations were measured by radioimmunoassay, using the DiaSorin kit, America. The objects were assigned into four groups: vitamin D deficient group (group A, 25(OH)D < 25 nmol/L), insufficient group(group B, 25 nmol/L < 25(OH)D < or = 50 nmol/L), normal group (group C, 50 nmol/L < 25(OH)D < or = 75 nmol/L) and enough group (group D, 25(OH)D > 75 nmol/L). The BMD at total, lumbar spine (L(2-4)) and proximal femur were measured by dual-energy X-ray absorptiometry (DEXA).</p><p><b>RESULTS</b>The mean concentration of serum 25(OH)D concentration was (36.0 +/- 14.6) nmol/L, BMD at total and proximal femur were respectively (0.829 +/- 0.090) and (0.679 +/- 0.106) g/cm(2). The mean BMD at total of group A, B, C + D were respectively (0.811 +/- 0.077), (0.825 +/- 0.088) and (0.864 +/- 0.112) g/cm(2)(F = 16.93, P < 0.01), and BMD at proximal femur of group A, B, C + D were respectively (0.666 +/- 0.107), (0.673 +/- 0.099) and (0.725 +/- 0.117) g/cm(2)(F = 18.36, P < 0.01). The 25(OH)D level was positively correlated with BMD at total body and proximal femur (r values were 0.17 and 0.18, both P values < 0.05).</p><p><b>CONCLUSION</b>Vitamin D status was highly correlated with BMD at lumbar spine (L(2-4)), proximal femur, pelvis and limbs for the postmenopausal older women.</p>

Body vitamin D content and its relationship with body composition of children in Huairou district of Beijing / 中华流行病学杂志

Objective To analyze vitamin D concentration and its association with body composition of children in Huairou district of Beijing, to provide evidence for evaluation and improvement of nutritional status of vitamin D in children. Methods Totally, 381 children aged 7-11 years were recruited in Huairou district of Beijing(40.3°N). Samples of overnight fasting venous blood (drawn between 0630 and 0900) were obtained in late March. Serum 25-hydroxyvitamin D [25(OH)D] concentration was determined by ELISA kits (IDS Ltd, UK). Body composition indices of the whole body, the distal and proximal forearm were measured using dual-energy X-ray absorptiometry (DEXA, Norland, US A). Results The average serum 25 (OH) D concentration of all subjects was (44.4±12.5) nmol/L. The percentage of vitamin D insufficient [serum 25(OH) D≤ 50 nmol/L ] reached as high as 68.5% (261 people). The 25 (OH) D concentration of boys (46.3 nmol/L± 13.3 nmol/L) was significantly higher than that of girls (42.0 nmol/L±11.1 nmol/L), (t=3.38,P< 0.01). Between the serum 25(OH)D concentration and lean body mass of proximal forearm, distal forearm, whole body, and four limbs, significant positive correlations (r=0.13-0.19,P<0.05) were observed. After age, gender, height and weight were under controlled for, correlations between the serum 25(OH)D concentration and lean body mass at proximal forearm, and the two lower limbs still existed (r=0.12-0.14,P<0.05). The serum 25(OH)D concentration, the percentage of body fat at proximal forearm, and distal forearm were negatively correlated (r=-0.14, P<0.05;r=-0.11, P< 0.05). However, after adjusting for confounding effects, this correlation disappeared. No significant correlation between the serum 25 (OH)D concentration and body fat was observed at any position. Conclusion Vitamin D deficiency was common in children of suburb area of Beijing. Vitamin D status was positively associated with the lean body mass.

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>

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 / 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>

Association of estrogen receptor-alpha gene Pvull polymorphisms with the effect of calcium supplementation on skeletal development in Chinese pubertal girls / 生物医学与环境科学（英文）

<p><b>OBJECTIVE</b>To investigate the association of estrogen receptor alpha (ER-alpha) PvuII polymorphisms with the effect of calcium supplementation on bone development in Chinese pubertal girls, and to study the importance of calcium supplementation by maximizing the peak bone mass at their pubertal stage for bone development and osteoporosis prevention and the role of estrogen in regulating bone mass.</p><p><b>METHODS</b>Ninety-four pubertal girls were recruited in the study and divided into two groups and three sub-groups according to the ER-alpha PvuII polymorphisms. One year before and after calcium supplementation, bone mineral density (BMD) was measured by DEXA, while BGP, BAP, TRACP5b, and 25-OH-VitD(3), as well as estrogen were detected by ELISA. Analysis of covariance was used to examine the effect of ER-alpha polymorphisms on bone development.</p><p><b>RESULTS</b>The absolute increase and percentage change of BGP were significantly higher in the supplemented group than in the control group (P<0.05). In the intervened group, The increase and percentage change of the total body and radio distal 1/3 BMD were higher in PP than in PP genotype (P<0.05), and the increase of BAP in Pp was also higher than PP in the same group (P<0.05).</p><p><b>CONCLUSION</b>PP genotype shows a better response to calcium supplementation than the other PvuII polymorphisms.</p>

Application of the WHO growth reference (2007) to assess the nutritional status of children in China / 生物医学与环境科学（英文）

<p><b>OBJECTIVE</b>To assess the nutrition status of children and adolescents in China using the WHO growth reference (2007) in comparison with that defined by the International Obesity Task Force (IOTF) and the Working Group on Obesity in China (WGOC).</p><p><b>METHODS</b>Overweight and obesity were defined by age-, sex-, specific BMI reference developed by WHO (2007), IOTF (2000), and WGOC (2004), respectively. Stunting and thinness were defined as height and BMI less than two standard deviations (SD) of the WHO growth reference (2007), respectively. Data of children and adolescents aged 5 to 19 years (n=54,857, 28,273 boys, 26,584 girls) from the 2002 China National Nutrition and Health Survey (CNNHS) were used in the study.</p><p><b>RESULTS</b>The prevalence of overweight, obesity, stunting and thinness among Chinese children and adolescents aged 5-19 years was 5.0%, 1.2%, 13.8%, and 7.4%, respectively when the WHO growth reference (2007) was used, whereas the estimated absolute total number affected by these 4 conditions were 14.6, 3.7, 40.6, and 21.8 million, respectively. The prevalence of overweight and obesity was 18.1% in large cities, while the stunting prevalence was 25.1% in rural 4. Obesity prevalence assessed by the WHO growth reference was higher than that as assessed by the IOTF reference, and obesity prevalence assessed by the WGOC reference was lower than that as assessed by the IOTF reference.</p><p><b>CONCLUSION</b>The nutritional status of children and adolescents is not equal in different areas of China. Stunting is still the main health problem of the poor, while overweight and obesity are the main health problems in large cities.</p>

Interactions between effects of estrogen receptor gene polymorphisms on BMD and experiences of the first spermorrhea in Chinese Han boys / 生物医学与环境科学（英文）

<p><b>OBJECTIVE</b>To study the interaction between polymorphisms of estrogen receptor (ER) gene and puberty on bone mineral density (BMD).</p><p><b>METHODS</b>One hundred and forty-six boys aged 13-17 years were divided into two groups according to their first spermorrhea. DNA was analyzed for Xba I and Pvu II genotypes by PCR-RFLP. BMD of the total body, forearm and lumbar spine was measured by dual-energy X-ray absorptiometry (DXA). The relationship between polymorphisms of ER gene and BMD in these two groups was analyzed.</p><p><b>RESULTS</b>The BMD at all sites in the spermorrhea group was significantly higher than that in the un-spermorrhea group. The independent contribution of ER genotypes to BMD at two pubertal stages was analyzed after adjusting co-variables. In the un-spermorrhea group, the BMD at distal 1/10 and 1/3 forearm of those carrying pp genotype was significantly higher than that of the non-carries, whereas in the spermorrhea group BMD in those carrying the same genotype was significantly lower than that in the non-carriers. Similar results were obtained by haplotype analysis. Multiple stepwise regression analysis showed that body weight, age and the first spermorrehea were the dominant determinants for BMD. BMD at forearm might be influenced by interaction between ER genotype and the first spermorrehea.</p><p><b>CONCLUSION</b>The polymorphisms of ER gene play a different role in BMD influenced by the first spermorrhea. Chinese boys carrying p or x allele should pay more attention to their bone mass.</p>