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Objective: To analyze the trends of the age of menarche among Chinese Han girls aged 9 to 18 years from 2010 to 2019. Methods: Data were extracted from the Chinese National Surveys on Students' Constitution and Health in 2010, 2014 and 2019. A total of 253 037 Han girls aged 9 to 18 years with complete data on menarche were selected in this study. They were asked one-on-one about their menstrual status, age and residence information. The median age of menarche was estimated by probability regression. U tests were used to compare the difference in median age at menarche in different years. Results: The median age at menarche (95%CI) among Chinese Han girls was 12.47 (12.09-12.83) years in 2010, 12.17 (11.95-12.38) years in 2014 and 12.05 (10.82-13.08) years in 2019, respectively. Compared with that in 2010, the median age at menarche in 2019 decreased by 0.42 years (U=-77.27, P<0.001). The annual average changes were -0.076 years from 2010 to 2014 (U=-57.19, P<0.001) and -0.023 years from 2014 to 2019 (U=-21.41, P<0.001), respectively. The average annual changes in urban areas in the periods of 2010 to 2014 and 2014 to 2019 were -0.071 years and 0.006 years, respectively, while those in rural areas were -0.082 years and -0.053 years, respectively. The average annual changes in the regions of north, northeast, east, south central, southwest and northwest were -0.064, -0.099, -0.091, -0.080, -0.096 and -0.041 years in the period of 2010 to 2014 and 0.001, -0.040, -0.002, -0.005, -0.043 and -0.081 years in the period of 2014 to 2019. Conclusion: The age of menarche among Chinese Han girls aged 9 to 18 years shows an advanced trend from 2010 to 2019, and the trends in urban and rural areas and different regions have different characteristics.
Subject(s)
Female , Humans , Child , Adolescent , Menarche , Probability , East Asian PeopleABSTRACT
OBJECTIVE@#To analyze the association between outdoor artificial light-at-night (ALAN) exposure and overweight and obesity among children and adolescents aged 9 to 18 years in China.@*METHODS@#Using follow-up data of 5 540 children and adolescents aged 9 to 18 years conducted from November 2019 to November 2020 in eight provinces of China, latitude and longitude were determined based on school addresses, and the mean monthly average nighttime irradiance at the location of 116 schools was extracted by the nearest neighbor method to obtain the mean outdoor ALAN exposure [unit: nW/(cm2·sr)] for each school. Four indicators of overweight and obesity outcomes were included: Baseline overweight and obesity, persistent overweight and obesity, overweight and obesity progression and overweight and obesity incidence. Mixed effects Logistic regression was used to explore the association between ALAN exposure levels (divided into quintiles Q1-Q5) and baseline overweight and obesity, persistent overweight and obesity, overweight and obesity progression and overweight and obesity incidence. In addition, a natural cubic spline function was used to explore the exposure response association between ALAN exposure (a continuous variable) and the outcomes.@*RESULTS@#The prevalence of baseline overweight and obesity, persistent overweight and obesity, overweight and obesity progression and overweight and obesity incidence among the children and adolescents in this study were 21.6%, 16.3%, 2.9% and 12.8%, respectively. The OR value for the association between ALAN exposure and baseline overweight and obesity was statistically significant when ALAN exposure levels reached Q4 or Q5, 1.90 (95%CI: 1.26-2.86) and 1.77 (95%CI: 1.11-2.83), respectively, compared with the children and adolescents in the Q1 group of ALAN exposure. Similar to the results for baseline overweight and obesity, the OR values for the association with persistent overweight and obesity were 1.89 (95%CI: 1.20-2.99) and 1.82 (95%CI: 1.08-3.06) when ALAN exposure levels reached Q4 or Q5, respectively, but none of the OR values for the association between ALAN and overweight and obesity progression and overweight and obesity incidence were statistically significant. Fitting a natural cubic spline function showed a non-linear trend between ALAN exposure and persistent overweight and obesity.@*CONCLUSION@#There is a positive association between ALAN exposure and overweight and obesity in children and adolescents, and the promotion of overweight obesity in children and adolescents by ALAN tends to have a cumulative effect rather than an immediate effect. In the future, while focusing on the common risk factors for overweight and obesity in children and adolescents, there is a need to improve the overweight and obesity-causing nighttime light exposure environment.
Subject(s)
Humans , Adolescent , Child , Overweight/etiology , Pediatric Obesity/etiology , Light Pollution , Risk Factors , China/epidemiologyABSTRACT
Objective: To analyze the perceived exercise benefits and barriers and their association with physical activity time in Chinese Han children and adolescents aged 9-18 years. Methods: Data were extracted from the 2019 Chinese National Survey on Students' Constitution and Health and a total of 163 656 children and adolescents aged 9-18 years in Han ethnic group were included in the analysis. Mann-Whitney U test and Kruskal-Wallis test were used to compare the perceived exercise benefits score, perceived exercise barriers score and perceived exercise benefits to barriers ratio in the children and adolescents with different demographic characteristics and physical activity time. The differences in physical activity time in subgroups were compared with χ2 tests. log-binomial regression model was used to evaluate the association between physical activity time and perceived exercise benefits and barriers. Results: The M (Q1,Q3) of the perceived exercise benefits score, perceived exercise barriers score, and perceived exercise benefits to barriers ratio in the children and adolescents were 4.11 (3.78, 4.78), 2.70 (2.10, 3.20) and 1.55 (1.22, 2.07), respectively. Children and adolescents living in urban area, boys, those at younger age and those with physical activity time ≥1 hour had higher perceived exercise benefits score and perceived exercise benefits to barriers ratio, but lower perceived exercise barriers score (all P<0.001). The prevalence of physical activity time ≥1 hour was 41.4% in the children and adolescents. In the log-binomial model with two variables of perceived exercise benefits score and perceived exercise barriers score, for each 1-point increase in the perceived exercise benefits, the possibility of physical activity time ≥1 hour increased by 11% (OR=1.11, 95%CI: 1.10-1.12), and for each 1-point increase in the perceived exercise barriers, the possibility of physical activity time ≥1 hour decreased by 15% (OR=0.85, 95%CI: 0.84-0.85). In the log-binomial model with variable of perceived exercise benefits to barriers ratio, for each 1-point increase in the perceived exercise benefits to barriers ratio, the possibility of physical activity time ≥1 hour increased by 12% (OR=1.12, 95%CI: 1.11-1.12). Conclusion: The perceived exercise benefits and barriers are significantly associated with physical activity time in children and adolescents in China.
Subject(s)
Adolescent , Child , Humans , Male , Female , Asian People , China , Ethnicity , Exercise , StudentsABSTRACT
Objective: To analyze the trend of the detection rate of myopia among Chinese Han children and adolescents aged 7-18 years from 2010 to 2019. Methods: Data from the Chinese National Survey on Students' Constitution and Health in 2010, 2014 and 2019 were used, and about 213 833, 212 742 and 209 942 Han students aged 7-18 years were included in this study. The χ² test was used to compare the differences in the prevalence of myopia among the subgroups in the survey year, and logistic regression was used to compare the differences in the prevalence of myopia between different years. A curve-fitting method was used to obtain the growth rate of myopia among Han Chinese students from 2010 to 2019, and the differences in the change of myopia between different age groups were analyzed. Results: In 2019, the overall detection rate of myopia among Chinese Han children and adolescents aged 7-18 was 60.1%. The detection rate of urban students (62.7%) was higher than that of rural students (57.4%) and the detection rate of girls (63.5%) was higher than that of boys (56.7%). In 2019, the regional disparities were large in the detection rate of myopia in various provinces, with the lowest in Guizhou (49.6%) and the highest in Zhejiang (71.3%). The detection rate of myopia showed an upward trend from 2010 to 2019, from 55.5% in 2010 to 57.1% in 2014, and finally to 60.1% in 2019. The gap in the detection rate of myopia between urban and rural children and adolescents gradually shrank. The average annual growth rate of myopia detection rate from 2014 to 2019 was 0.6 percentage points per year, higher than that from 2010 to 2014 about 0.4 percentage points per year. The peak age of the growth rate of myopia detection rate decreased from 12 years in 2010 to 10 years in 2014, and finally to 7 years in 2019. Conclusions: The detection rate of myopia among Chinese Han children and adolescents is still at a high level, and the peak age of the growth rate of myopia detection rate continues to advance.
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Objective: To analyze the prevalence trend of malnutrition among Chinese Han children and adolescents aged 7-18 years from 2010 to 2019. Methods: Based on the data from the Chinese National Surveys on Students' Constitution and Health in 2010, 2014 and 2019, about 215 102, 214 268 and 212 713 Han students aged 7-18 years were included in this study. According to the National Screening Standard for Malnutrition of School-age Children and Adolescents, the detection rate of malnutrition among Chinese Han children and adolescents aged 7-18 was calculated, and the prevalence trend of malnutrition from 2010 to 2019 was analyzed. Results: In 2019, the detection rate of malnutrition among Chinese Han students aged 7-18 years was 8.64% (18 381/212 713), of which the rate of growth retardation, moderate-to-severe wasting and mild wasting was 0.50% (1 062/212 713), 3.25% (6 914/212 713) and 4.89% (10 405/212 713), respectively. In 2019, the detection rate of malnutrition in these boys was higher than that of girls (9.97% vs. 7.31%), and the detection rate in rural areas was higher than that in cities (9.30% vs. 7.98%). The detection rates were 9.74% (5 252/53 916), 8.17% (4 408/53 937), 7.29% (3 885/53 310), and 9.38% (4 836/51 550) in 7-9, 10-12, 13-15, and 16-18 years groups, and 8.14% (6 563/80 618), 7.61% (4 237/55 694) and 9.92% (7 581/76 401) in the eastern, central, and western regions. Malnutrition among students in China was mainly caused by mild wasting, and the detection rate of growth retardation accounted for only 5.78% (1 062/18 381). Malnutrition was mostly concentrated in the southwest region, and the rate was relatively low in eastern provinces. In three surveys from 2010 to 2019, the detection rate of malnutrition among Han students aged 7-18 in China decreased gradually, and the differences were statistically significant (P<0.05). Among them, the detection rates in western rural areas decreased significantly, as well as the gap between urban and rural areas. Compared with that in 2014, the detection rate of malnutrition in Shandong, Hunan, Qinghai and Hainan provinces in 2019 decreased significantly (P<0.05). Conclusion: In 2019, the malnutrition of Chinese children and adolescents aged 7-18 years is dominated by wasting malnutrition. The detection rate shows a downward trend from 2010 to 2019, with regional differences.
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Objective: To analyze and predict the epidemic trend of overweight and obesity among children and adolescents aged 7-18 years in China from 1985 to 2019. Methods: Data were collected from the Chinese National Survey on Students Constitution and Health in 1985, 1995, 2000, 2005, 2010, 2014, and 2019 with the sample size of 409 945, 204 931, 209 209, 234 420, 215 317, 214 353, and 212 711, respectively. Overweight and obesity were evaluated according to the "classification standard of the weight index value of overweight and obesity screening for Chinese school-age children and adolescents" of the Working Group on Obesity in China (WGOC). The detection rate and average annual growth rate of overweight and obesity, and single obesity among children and adolescents aged 7-18 years were calculated, and ArcGis10.6 software was used to analyze the difference in the prevalence of overweight and obesity among children and adolescents in different regions in 2019. Polynomial regression function was used to fit the prevalence and average annual growth rate of overweight and obesity, and single obesity among children and adolescents from 1985 to 2019, and to predict the prevalence of overweight and obesity and single obesity among children and adolescents in China. Results: In 2019, the total prevalence of overweight and obesity among children and adolescents aged 7-18 years in China was 23.4%, and the prevalence of single obesity was 9.6%. The prevalence of overweight and obesity among urban children and adolescents was higher than that in rural areas (25.4% vs. 21.5%), and the prevalence in boys was higher than that in girls (28.4% vs. 18.4%) (both P values<0.001). In 2019, there was a large regional disparity in the prevalence of overweight and obesity in different provinces, with the lowest in Guangdong (12.2%) and the highest in Shandong (38.9%), and the high epidemic areas were mainly concentrated in North China and Northeast China. From 1985 to 2019, the prevalence of overweight and obesity among children and adolescents aged 7-18 years in China increased from 1.2% to 23.4%, with an increase of 18.1 times, while the prevalence of obesity alone increased from 0.1% to 9.6%, with an increase of 75.6 times. The prevalence of overweight and obesity in urban boys, urban girls, rural boys and rural girls increased from 1.3%, 1.5%, 0.5%, and 1.6% in 1985 to 31.2%, 19.4%, 25.6%, and 17.4% in 2019, with an increase of 22.3, 11.7, 54.2, and 10.1 times, respectively. According to the prediction model, the prevalence of overweight and obesity among children and adolescents aged 7-18 years in China will increase from 23.4% in 2019 to 32.7% in 2030, and the prevalence of obesity alone will increase from 9.6% in 2019 to 15.1% in 2030. The growth of rural children and adolescents is obvious. By 2025, the prevalence of overweight and obesity among rural children and adolescents in China will comprehensively exceed that of urban, and there will be an "urban-rural reversal" phenomenon. At the same time, the prevalence of children's obesity in China's low, medium and high epidemic areas will also continue to increase. By 2035, the prevalence of overweight and obesity among children and adolescents in medium epidemic areas will exceed that in high epidemic areas, and there will be a "provincial reversal" phenomenon. Conclusion: From 1985 to 2019, the overweight and obesity of children and adolescents in China will continue to grow rapidly with large regional differences.
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Objective: To analyze the long-term trend of the age of spermarche among Chinese Han boys aged 11 to 18 from 2010 to 2019 and its association with nutritional status. Methods: The data from Chinese National Surveys on Students' Constitution and Health in 2010, 2014 and 2019 were used. The age, residence and spermarche of the participants were collected by questionnaire, and their height and weight were measured. A total of 184 633 Han boys aged 11‒18 years with complete data on spermarche, height, and weight were included in this study. The probability regression method was used to calculate the median age (95%CI) at spermarche in different areas, and the trend of age at spermarche in different groups was compared. The multivariate logistic regression model was used to analyze the association between nutritional status and spermarche of Chinese Han boys aged 11‒18 years. Results: The median age of spermarche (95%CI) was 13.85 (13.45-14.22) years old among Chinese Han boys aged 11‒18 years in 2019, with 0.18 years earlier than that in 2010. The median age at spermarche in urban and rural boys was 13.89 and 13.81 years, respectively. Compared with that in 2010, the age at spermarche in urban and rural boys was 0.08 and 0.27 years earlier, respectively. After adjusting for age, province and urban/rural areas, compared with normal weight, spermarche was negatively associated with wasting and positively associated with overweight and obesity, with OR (95%CI) about 0.73 (0.67-0.80), 1.09 (1.02-1.17) and 1.09 (1.01-1.18), respectively. Conclusion: The age of spermarche generally shows an advanced trend among Chinese Han boys and is associated with nutritional status.
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Objective: To analyze the trends of the age of menarche among Chinese Han girls aged 9 to 18 years from 2010 to 2019. Methods: Data were extracted from the Chinese National Surveys on Students' Constitution and Health in 2010, 2014 and 2019. A total of 253 037 Han girls aged 9 to 18 years with complete data on menarche were selected in this study. They were asked one-on-one about their menstrual status, age and residence information. The median age of menarche was estimated by probability regression. U tests were used to compare the difference in median age at menarche in different years. Results: The median age at menarche (95%CI) among Chinese Han girls was 12.47 (12.09-12.83) years in 2010, 12.17 (11.95-12.38) years in 2014 and 12.05 (10.82-13.08) years in 2019, respectively. Compared with that in 2010, the median age at menarche in 2019 decreased by 0.42 years (U=-77.27, P<0.001). The annual average changes were-0.076 years from 2010 to 2014 (U=-57.19, P<0.001) and-0.023 years from 2014 to 2019 (U=-21.41, P<0.001), respectively. The average annual changes in urban areas in the periods of 2010 to 2014 and 2014 to 2019 were-0.071 years and 0.006 years, respectively, while those in rural areas were-0.082 years and-0.053 years, respectively. The average annual changes in the regions of north, northeast, east, south central, southwest and northwest were-0.064, -0.099, -0.091, -0.080, -0.096 and-0.041 years in the period of 2010 to 2014 and 0.001, -0.040, -0.002, -0.005, -0.043 and-0.081 years in the period of 2014 to 2019. Conclusion: The age of menarche among Chinese Han girls aged 9 to 18 years shows an advanced trend from 2010 to 2019, and the trends in urban and rural areas and different regions have different characteristics.
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OBJECTIVE@#To analyze the inequality of early marriage and adolescent fertility with respect to local economic development among Chinese females aged 15-19 years from 1990 to 2010.@*METHODS@#Aggregated data were extracted from the Chinese National Census from 1990 to 2010. We calculated the ever-married rate and fertility rate of female adolescents aged 15-19 years. Using gross domestic product (GDP) per capita as an indicator for socio-economic status of a province, we calculated the slope index of inequality (SII) and the concentration index (CI) to analyze the subnational inequalities of early marriage and adolescent fertility. Weighted linear regression models were also established to assess the associations between GDP per capita and the ever-married rate/fertility rate.@*RESULTS@#The ever-married rate for Chinese female adolescents aged 15-19 years decreased from 4.7% in 1990 to 1.2% in 2000, and rebounded to 2.1% in 2010. From 1990 to 2000, the fertility rate decreased from 22.0 per 1 000 to 6.0 per 1 000, and further decreased to 5.9 per 1 000 in 2010. In 1990, the socio-economic inequalities of the ever-married rate and fertility rate for female adolescents aged 15-19 years were not statistically significant (P for SII or CI>0.05). The values of SII revealed that, in 2000 and 2010, female adolescents with the lowest GDP per capita had an ever-married rate 2.4% (95%CI: 0.4-4.4) and 2.3% (95%CI: 0.3-4.2) higher than those with the highest GDP per capita, respectively. In the meantime, in 2000 and 2010, female adolescents with the lowest GDP per capita had a fertility rate 12.9 per 1 000 (95%CI: 5.4-20.5) and 9.3 per 1 000 (95%CI: 4.6-14.0) higher than those with the highest, respectively. In 2000 and 2010, the CIs for marriage were -0.32 (P=0.02) and -0.17 (P=0.03), respectively, and the CIs for childbirth were -0.37 (P<0.01) and -0.26 (P<0.01), respectively. In 2000, the ever-married rate and the fertility rate were estimated to increase by 1.4% (95%CI: 0.1-2.7) and 7.9 per 1 000 (95%CI: 2.9-12.8) with 100% increase in GDP per capita, respectively; in 2010, the numbers were 1.5% (95%CI: 0.1-2.9) and 6.7 per 1 000 (95%CI: 3.2-10.1), respectively.@*CONCLUSION@#Subnational socio-economic inequality of early marriage and adolescent fertility existed in 2000 and 2010. Female adolescents residing in less-developed areas were more likely to engage in early marriage and childbirth. Reducing income inequality and increasing education investment for poverty-stricken areas seem to be effective measures to reduce this inequality.
Subject(s)
Adolescent , Adult , Female , Humans , Young Adult , Economic Development , Fertility , Income , Marriage , Socioeconomic FactorsABSTRACT
OBJECTIVE@#To analyze the trends of prevalence of excellent health status and physical fitness among Chinese Han students aged 13 to 18 years from 1985 to 2014.@*METHODS@#In the study, 738 523 students aged 13 to 18 years were extracted from the 1985 to 2014 Chinese National Survey on Students' Constitution and Health. Height, weight, vital capacity and indicators of physical fitness were measured for each student. According to National Standards for Students' Physical Health (2014 Revision), students meeting an overall score ≥ 90.0 were considered to be of excellent health status and physical fitness. We used the Chi-square test to compare the differences in prevalence of excellent health status and physical fitness among different subgroups and draw maps of regional distribution of prevalence by using ArcGIS.@*RESULTS@#From 1985 to 2014, the average height, weight, and BMI for Chinese Han students aged 13 to 18 years increased consistently, while the average vital capacity and indicators of physical fitness fluctuated largely. The overall prevalence of excellent health status and physical fitness increased from 2.7% in 1985 to 4.4% in 1995, dropped consistently to 1.1% in 2005, rebounded 0.6 percentage points in 2010, and increased to 2.2% in 2014. In each survey year, the prevalence for the boys was always higher than for the girls (P<0.001), the prevalence for middle school students aged 13 to 15 years was always higher than for high school students aged 16-18 years (P<0.001), and the prevalence for students in eastern region was higher than in western and central regions (P<0.001). In 1985 and 1995, the prevalence in certain provinces in eastern and central regions was <1%. In 2005, almost half provinces (14/30) had a prevalence <1%. In 2014, provinces in eastern coastal areas had relatively high prevalence of excellent health status and physical fitness in students aged 13 to 18 years, while provinces in central and western regions had relatively low prevalence.@*CONCLUSION@#A fluctuating trend of the prevalence of excellent health status and physical fitness has been observed among Chinese Han students aged 13 to 18 years during the past three decades. There is great difference between the current prevalence of excellent health status and physical fitness and the goal of Outline of the Healthy China 2030 Plan, thus, the effective interventions and strategies for promoting students' physical activity and physical fitness are urgently needed in China.
Subject(s)
Adolescent , Female , Humans , Male , China , Health Status , Physical Fitness , Prevalence , StudentsABSTRACT
OBJECTIVE@#To analyze the situation of physical fitness among Chinese Han students in 2014, so as to develop the guideline of physical activity regarding to the targeted students and to provide bases for the improvements of students' physical fitness.@*METHODS@#Subjects were from 2014 Chinese National Surveys on Students' Constitution and Health (CNSSCH). In this survey, 212 401 Han students aged 7-18 years participated and the measurement of physical fitness completed. The qualified rates of indicators regarding to physical fitness were evaluated based on "National Students Constitutional Health Standards" (2014 revised edition). Logistic regression was used to assess the association between the indicators of pull ups (boys) and endurance run (boys and girls) and influencing factors.@*RESULTS@#In 2014, among the boys, the qualified rates of pull ups and endurance run were 18.7% and 76.6% respectively, while the qualified rate of endurance run was 80.6% among the girls. These two indicators were the weak items of physical fitness among the Chinese Han students. There was regional difference in the qualified rates of physical fitness, and the students in Zhejiang and Jiangsu provinces had higher qualified rates. Logistic regression showed that the urban students (OR=0.67), the students with malnutrition (OR=0.76), overweight (OR=0.32) or obesity (OR=0.12) were less likely to be qualified to pull ups; the students who had physical activity more than 1 h per day (OR=1.31) was more likely to be qualified to pull ups. The influencing factors of endurance run showed the similar pattern, in addition, the students with enough physical education (PE) were more likely to be qualified to endurance run, while the students with "Squeeze" or "no" PE class were less likely to be qualified to endurance run.@*CONCLUSION@#The pull ups and endurance run have become the weak items of the physical fitness among primary and secondary school students in our national and provincial levels. Based on ensuring physical exercise time and PE curriculum and class hours, as well as improving students' nutrition, we should also strengthen the rational design of physical exercise and ensure the balanced development of various items so as to improve the overall development of students' physical fitness.
Subject(s)
Adolescent , Child , Female , Humans , Male , Asian People , Exercise , Logistic Models , Obesity , Overweight , Physical Fitness , Students , Surveys and QuestionnairesABSTRACT
<p><b>OBJECTIVE</b>To explore the influencing factors on physical endurance among Chinese primary and middle school students aged 10-17.</p><p><b>METHODS</b>Data was used from "2010 National Physical Fitness and Health Surveillance", from which 68 458 primary and middle school students with complete information were selected. Good physical endurance was defined as endurance running time ≤ P 25 of same gender and age, poor physical endurance as ≥ P 75 of same gender and age. Difference of endurance running time in different physical endurance groups was compared; chi-square test, logistic regression and multiple level model were used to analyze influence of region, BMI, diet, exercise and exercise willingness on physical endurance.</p><p><b>RESULTS</b>There were 34 293 (50.0%) students of good physical endurance and 34 219 (50.0%) ones of poor physical endurance in 68 458 subjects. Percentage of good physical endurance was 53.8% (18 285/33 996) in rural students, higher than urban ones (46.3% (15 954/34 462)) (χ(2) = 384.16, P < 0.01). Percentage of good physical endurance was 12.2% (448/3660) in obese students, lower than normal (55.2% (28 183/51 028)), overweight (29.3% (2012/6874)) and emaciated ones (52.1% (3596/6896)) (χ(2) = 3840.08, P < 0.01). Percentage of good physical endurance was 52.5% (25 534/48 679) in students having breakfast everyday, higher than ones never having breakfast or 1-2 times per week (41.3% (3209/7768))(χ(2) = 438.31, P < 0.01). Percentage of good physical endurance was 51.7% (11 580/22 379) in students having milk everyday, slightly higher than ones never or sometimes having milk (49.2% (22 659/46 079)) (χ(2) = 39.84, P < 0.01). Percentage of good physical endurance was 55.3% (18 961/34 314) in students with adequate physical education class, higher than ones with inadequate class (44.7% (15 278/34 144)) (χ(2) = 756.41, P < 0.01). Percentage of good physical endurance was 58.6% (9484/16 195) in students with one hour exercise or more per day, higher than ones with less than one hour exercise (47.4% (24 755/52 263)) (χ(2) = 619.82, P < 0.01). Percentage of good physical endurance was 60.1% (19 287/32 118) in students who were "very willing" to take part in endurance running, higher than "generally willing" ones (45.4% (10 569/23 272)) and "not willing" ones (33.5% (4383/13 068)) (χ(2) = 2909.61, P < 0.01). Multiple level analysis revealed that risk of poor physical endurance was lower in rural students (OR = 0.80, 95%CI: 0.77-0.82) than urban ones. Risk in emaciated students (OR = 1.11, 95%CI: 1.05-1.17), overweight students (OR = 2.69, 95%CI: 2.55-2.85) and obese students (OR = 7.71, 95%CI: 6.97-8.52) was higher than normal ones. Concerning diet, risk of poor physical endurance in students never having breakfast or once to twice per week was highest (OR = 1.20, 95%CI: 1.13-1.26), followed by students having breakfast three to five times per week (OR = 1.13, 95%CI: 1.08-1.18); risk in students having one bag of milk per day was higher (OR = 1.09, 95%CI: 1.02-1.17) than ones having two bags. Concerning exercise, risk of poor physical endurance in students with inadequate physical education class (OR = 1.20, 95%CI: 1.13-1.26) and less than one hour exercise per day (OR = 1.34, 95%CI: 1.29-1.40) was higher than ones with adequate physical education class and one hour exercise or more respectively. Risk of poor physical endurance in students who were "generally willing" (OR = 1.67, 95%CI: 1.61-1.73) and "not willing" (OR = 2.72, 95%CI: 2.60-2.85) to take part in endurance running was higher than "very willing" ones.</p><p><b>CONCLUSION</b>Urban and rural residence, BMI, breakfast, milk, physical education class, exercise time and exercise willingness were related to primary and middle school students'physical endurance.</p>
Subject(s)
Adolescent , Child , Female , Humans , Male , Models, Statistical , Physical Endurance , Physical Fitness , StudentsABSTRACT
<p><b>OBJECTIVE</b>To explore the association between early menarche and physical fitness among adolescent girls in China.</p><p><b>METHODS</b>Research material was selected from the data of "2010 National Physical Fitness and Health Survey". Probability unit regression method was used to calculate the age of 10th percentile at menarche and menarche age before the 10th percentile was defined as early menarche(9.0-11.6 years old). A total of 1072 girls with early menarche were selected. Each girl with early menarche was matched with one girl from the same urban or rural locations who hadn't achieved menarche with the age difference less than 0.1 years. A total of 1072 girls without menarche were selected. Indicators of physical fitness included 50 m running, standing broad jump, 50 m×8 shuttle running and sit-ups. Differences of physical fitness between early menarche and without menarche were analyzed using t test stratified by age and urban/rural area. The multilevel models of single dependent variable and multiple dependent variables were used to analyze association between early menarche and physical fitness.</p><p><b>RESULTS</b>A total of 2144 students were put in this research. Among girls (11.0-11.6 years old) in urban areas, 50 m running, standing broad jump and sit-ups was (9.78 ± 0.85) s, (153.81 ± 18.59) cm, and 27.79 ± 10.25, respectively for those with early menarche, while in girls without menarche was (10.01 ± 0.90) s, (149.71 ± 18.72) cm and 26.28 ± 10.11, respectively. There were significant differences between two groups on all above variables (t values were 4.02, 3.43 and 2.31, respectively with all P values <0.01). Among girls in rural, 50 m×8 shuttle-running and sit-ups was (125.22 ± 15.57) s and 24.96 ± 8.97 for those with early menarche, while it was (120.92 ± 13.06) s and 22.96 ± 9.83 for those without menarche. There were significant differences between two groups on both variables(t values were 3.89 and 2.77 with both P values < 0.01). In addition, 50 m×8 shuttle-running in girls (10.0-10.9 years old) with early menarche was (128.52 ± 15.74) s and it was (123.89 ± 13.50) s in girls without menarche. The difference was significant (t = 2.14, P < 0.05). The multilevel analysis showed that 50 m running, standing broad jump and sit-ups in girls with early menarche was 0.12 s, 3.14 cm and 1.11 higher than girls without menarche (Waldχ(2) values were 4.00, 6.22 and 4.07, respectively with all P values < 0.05). But 50 m×8 shuttle-running in girls with early menarche was 1.95 s less than girls without menarche (Waldχ(2) = 3.96, P < 0.05).</p><p><b>CONCLUSION</b>Early menarche may be associated with higher speed fitness, leg power and muscle power and lower physical stamina.</p>
Subject(s)
Child , Female , Humans , China , Menarche , Physiology , Models, Statistical , Physical Fitness , Physiology , Rural Population , Students , Urban PopulationABSTRACT
Objective To analyze the trend of secular growth among the minority girls in China from 1985 to 2005 in order to develop national and local intervention strategies and measures to improve their physical fitness and health.Methods A total of 19 Chinese minoritt girls,including Mongolian,Hui,Zhuang,Korean,Tibetan,Miao,Buyi,Dong,Yao,Bai,Tujia,Hani,Dai,Lisu,Wa,Nakhi,Tu,Qiang and Salar were sampled from the 1985 and 2005 Chinese national surveys to study the students' physical fitness and health.Probit analyses were used to calculate age at menarche (AAM),and the heights and weights of 17-years-old girls in various minority groups.Results From 1985 to 2005,the increments of adult heights and weights increased significantly in many minority groups.The average height of girls aged 17 years old in each minority group had an increase of 150 cm in 2005.Ethnic groups with height growth rates of more than 1 cm per decade in girls aged 17 years old were Korean ( 1.47 cm/decade),Tujia( 1.38 crn/decade),Qiang ( 1.32 cm/decade),Bai ( 1.25 cm/decade),Hui ( 1.13 cm/decade) and Buyi ( 1.07 cm/decade).And the mionority ethnics with weight growth rates of more than 1 kg per decade in girls aged 17 years old were Mongolian ( 1.79 kg/decade),Korean ( 1.69 kg/decade),Tibetan ( 1.66 kg/decade),Nakhi ( 1.39 kg/decade),Qiang ( 1.28 kg/decade) and Hui ( 1.10 kg/decade).The overall AAM showed a downward rate in all the 19 minority groups,but with different degrees.Tujia,Yao and Nakhi showed the largest reductions,with AAMs as 2.15,1.76 and 1.38 years earlier in 2005 than in 1985,respectively.Conclusion Our data suggested that the downward secular trend in AAMs and the increments of adult heights might reflect the secular growth change in the major minority groups during the past 20 years,but there was an obvious disequilibrium of puberty development and increments of heights in adults between the minority groups.
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<p><b>OBJECTIVE</b>To analyze the trend of overweight and obesity in students in China during 1985 - 2010.</p><p><b>METHODS</b>The data were from Chinese National Survey on Students Constitution and Health in 1985, 1995, 2000, 2005 and 2010, and the sample sizes were 204 977, 216 786, 234 421, 215 319, respectively. BMI was calculated with height and weight. The prevalence of overweight and obesity as well as the rates of increase were described based on the BMI percentile criteria of Working Group on Obesity in China (WGOC).</p><p><b>RESULTS</b>In 2010, the prevalence of overweight and obesity in four groups students (urban boys, urban girls, rural boys, and rural girls aged 7 - 18 years) were 23.23% (12 503/53 830), 13.76% (7 414/53 857), 12.72% (6 839/53 744), 8.56% (4 612/53 888), respectively, which were higher in boys and urban, and reached the peak 17.14% (18 463/107 741) in students aged 7 - 12 years. The prevalences of obesity were 0.44% (8/1800) - 21.67% (390/1800) among children aged 7 - 18 years in different provinces. The prevalence of overweight and obesity during 1985 - 1995, 1995 - 2000, 2000 - 2005 and 2005 - 2010 increased 0.10%, 0.30%, 0.23%, 0.23%, respectively, and the increase rate was higher in urban than in rural during 1985 - 2005. During 1985 - 1995, the increase rate of obesity in four groups students were 0.20%, 0.13%, 0.05% and 0.03%, respectively. During 2005 - 2010, the increase rates of obesity in four groups of students were 0.30%, 0.10%, 0.34%, 0.17%, respectively, and the increase rate was higher in rural than in urban.</p><p><b>CONCLUSION</b>The prevalence of obesity among 7 - 18 years-old children increased rapidly during the 1985-2000, and the increase rate of obesity in rural exceeded that in urban during 2005 - 2010.</p>
Subject(s)
Adolescent , Child , Female , Humans , Male , Body Mass Index , China , Epidemiology , Health Surveys , Obesity , Epidemiology , Overweight , Epidemiology , Rural Population , Students , Urban PopulationABSTRACT
<p><b>OBJECTIVE</b>To explore the associations between behavioral risk factors and overweight and obesity among Chinese primary and middle school students in 2010.</p><p><b>METHODS</b>A total of 149 912 primary and middle school students aged 9 - 18 were selected from "2010 National Physical Fitness and Health Surveillance" while underweight students excluded. Questionnaires and height, weight and other physical index were performed. Logistic regression was used to analyze the association between overweight, obesity and sleep time, diet, physical exercise intention and behavior as well as sedentary behavior.</p><p><b>RESULTS</b>Of students surveyed, the proportion of short sleep time was higher in obese students than in normal weight students, the prevalence of short sleep time was 93.60% (118 394/126 491), 94.39% (15 053/15 947) and 95.09% (6782/7132) in normal weight, overweight and obese students, respectively (P < 0.05); the proportion of egg intake with no more than 3 times per week was lower in obese students than in normal weight students (56.49% (4025/7125) vs 65.25% (82 518/126 464)) (P < 0.05); the proportion of never drinking milk was lower in obese students than in normal weight students (7.08% (505/7134) vs 7.55% (9 545/126 503)) (P < 0.05); and when compared with those of normal (29.53%, 37 354/126 482), more overweight students reported that they had spent 2 or more hours on homework (30.17%, 4 809/15 941) (P < 0.05). The proportions of physical activity intentions were significantly lower in obesity group of male students than those of normal male group, and the proportion of liking physical education, being willing to participate in the extracurricular sports activities, and being willing to participate long running exercise was 67.7% (4828/7134), 71.2% (5083/7135) and 35.9% (2560/7135) in obese students compared with 68.6% (86 776/126 511), 72.6% (91 814/126 509) and 47.4% (59 914/126 512) in normal weigh students, respectively. In the 13 - 15 age group, the proportion of having been physically active for a total of at least 60 minutes per day was lower in obese group (19.87%, 376/1893) than in normal group (20.66%, 8 253/39 941) (P < 0.01). Logistic regression analysis showed that the students with short sleep time were more likely to get obesity than those without short sleep time (adjusted odds ratio (AOR): 1.11, 95%CI: 1.00 - 1.25). Egg intake with no more than 3 times per week was negatively associated with the probabilities of being at risk for obesity (AOR: 0.88, 95%CI: 0.83 - 0.92), while, never drinking milk was independently related to obesity (AOR: 1.14, 95%CI: 1.03 - 1.25). Disliking physical education (AOR: 1.23, 95%CI: 1.16 - 1.30), unwilling to participate long running exercise (AOR: 2.16, 95%CI: 2.05 - 2.28) and spending 2 or more hours on homework (AOR: 1.09, 95%CI: 1.02 - 1.15) were independently related to obesity. The patterns of influence factors in different groups were not alike.</p><p><b>CONCLUSION</b>Overweight and obesity prevalence was higher in China's primary and middle school students in 2010, and the bad dietary behavior, static life style were highly interconnected.</p>
Subject(s)
Adolescent , Child , Female , Humans , Male , China , Epidemiology , Exercise , Health Behavior , Health Surveys , Life Style , Logistic Models , Obesity , Epidemiology , Overweight , Epidemiology , Risk Factors , Students , Surveys and QuestionnairesABSTRACT
<p><b>OBJECTIVE</b>To study the effects of overweight and obesity on physical function (including systolic blood pressure (SBP), diastolic blood pressure (DBP), pulse, weight vital capacity index) in children and adolescents.</p><p><b>METHODS</b>The data of 2010 Chinese National Survey on Students Constitution and Health was analyzed. The samples of overweight and normal-weight group were randomly selected from the data by matching gender, urban or rural for getting the same number sample size as obese group (10 601 each group). The students aged 7 - 18 years were classified into 3 groups by BMI percentiles (P₅, P₁₅, P₂₅, P₅₀, P₇₅, P₈₅ and P₉₅), to analyze the change of physical function along with BMI percentile.</p><p><b>RESULTS</b>Compared to the normal-weigh group, SBP of the obese boys of all age groups increased by 8.0 - 12.0 mm Hg, DBP increased by 4.7 - 5.9 mm Hg, while SBP of the obese girls increased by 7.5 - 11.6 mm Hg, DBP increased by 4.7 - 6.1 mm Hg, with statistical significance (P < 0.05). In 13 - 15-year group, pulse of obese boys was 0.8 times/min higher than that of normal-weight. In 16 - 18-year group, pulse of obese boys was 1.1 times/min higher than that of overweight or normal-weight, while pulse of obese girls were 1.5 and 1.7 times/min higher than that of overweight and normal-weight, respectively (P < 0.05). Pulses in boys aged 7 - 9 years when BMI were P₅, P₅₀, P(95) were 87.63, 87.00, 87.83 times/min, and pulses in boys aged 10 - 12 were 85.66, 85.30, 85.43 times/min, respectively. Pulses in boys aged 13 - 15 years when BMI were P₅, P₅₀, P₉₅ were 82.60, 81.39, 82.34 times/min, and pulses in boys aged 16 - 18 years were 80.15, 79.00, 79.98 times/min. In both boys and girls of all age groups, weight vital capacity index had the trend of obese < overweight < normal-weight (P < 0.05). Compared to the normal-weight group, weight vital capacity index of overweight boys decreased by 6.4 - 8.4 ml/kg, that of obese boys decreased by 11.9 - 14.8 ml/kg, while that of overweight girls decreased by 5.3 - 7.7 ml/kg, that of obese girls decreased 11.0 - 11.5 ml/kg.</p><p><b>CONCLUSION</b>Compared to the normal-weight, overweight and obese children and adolescents had elevated blood pressure, increased pulse, decreased weight vital capacity index.</p>
Subject(s)
Adolescent , Child , Female , Humans , Male , China , Epidemiology , Ethnicity , Obesity , Epidemiology , Overweight , Epidemiology , Risk Factors , StudentsABSTRACT
<p><b>OBJECTIVE</b>To analyze the current situation of semenarche in boys aged 11 - 18 of 18 Chinese ethnic minority, and compare the average age of semenarche with Chinese Han boys from the same province or autonomous region.</p><p><b>METHODS</b>The average age of semenarche in various ethnic minority groups of Chinese boys who participated in 2005 National Physical Fitness and Health Surveillance were calculated. The sample size of ethnic minority boys was 16 267, and the ethnic minorities were Mongolian, Hui, Tibetan, Korean, Zhuang, Miao, Buyi, Dong, Shui, Tujia, Bai, Hani, Dai, Lisu, Wa, Naxi, Li and Tu. The local Han boys semenarche were also surveyed in 2005 National Physical Fitness and Health Surveillance. Probability unit regression, chi2 test, U test and dynamic clustering were used to calculate and analyze the average age of semenarche.</p><p><b>RESULTS</b>In the 13 years old group,the percentage of semenarche in Dong was lowest (5.00%, 5/100), while that in Li was the highest (68.35%, 54/79) (P<0.01). In the 14 and 15 years old group,the percentages of semenarche in Shui were the lowest (17.02%, 16/94; 22.83%, 21/92, respectively) (all P values <0.01), while the percentages in Zhuang were the highest (94.33%, 183/194; 98.45%, 191/194, respectively).When reached 18 years old, 97.85% (2137/2184) ethnic minority boys experienced semenarche. The top 3 ethnic minority groups in average age of semenarche were Korean (12.37 years old), Zhuang (13.34 years old) and Naxi (13.36 years old); and the last 3 ethnic minority groups were Shui (16.19 years old), Bai (15.27 years old) and Tu (15.19 years old). The average age of semenarche in Zhuang was 1.34 years earlier than that of Han boys from Guangxi Zhuang autonomous region; the average age in Korean was 1.28 years earlier than that of Han boys from Jilin province; and the average ages in Naxi and Dai were 0. 89 years and 0. 17 years earlier than that of Han boys from Yunnan province, respectively (all P values < 0. 01). The cluster analysis indicated that the 18 ethnic minority groups could be classified into two groups: Zhuang, Naxi, Li and Korean were classified into earlier age group of semenarche, and the other 14 ethnic minority groups were belonged to later age group of semenarche.</p><p><b>CONCLUSION</b>There was a large variation among different ethnic minority groups in terms of average age of semenarche. The semenarche was earlier in Zhuang, Korean, Naxi, and Dai, compared with local Han boys.</p>
Subject(s)
Adolescent , Child , Humans , Male , Adolescent Development , Asian People , China , Ethnology , Minority Groups , Semen , Sexual MaturationABSTRACT
Objective To describe the characteristics of sexual debut among college students in China to provide appropriate sex education in that population. Methods An anonymous questionnaire survey was conducted among 33 653 college students selected by multi-stage stratified cluster sampling method in 18 provinces and cities of China. Results The percentage of students who had initiated sexual intercourse before age 14 was 1.9%. Overall, male students (2.8%) were significantly more likely to have initiated sexual intercourse before age 14, than female students (1.1%). The percentage of students who had initiated sexual intercourse from age 15 to 18 was 6.4% in males versus 2.1% in females. while the rates of students who had initiated sexual intercourse after age 19 were 6.9% in males and 2.6% in females. The first sexual intercourse was significantly associated with parental educational attainment, geographic location and family structure. Students whose parents were relatively well educated, living in the western areas of the country China, or with nucleus/extensive families were more likely to have early sex in their puberties. Conclusion Sexual education should be strengthened especially in the western areas, and targeted on the students whose parents with relatively higher educational background or who were from extensive families.
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<p><b>OBJECTIVE</b>To analyze the geographic distribution and 10 years' change of spermarche in Chinese boys of Hangroup aged 11 - 18.</p><p><b>METHODS</b>Calculate the average age of spermarche of Chinese boys who participated in National Physical Fitness and Health Surveillance in 2005 and 1995. The sample size of boys was 69 320 in 2005, 68 992 in 1995 National Physical Fitness and Health Surveillance, respectively. The geographic distribution of Chinese boys were categorized into 6 areas as north, northeast, east, south central, southwest and northwest by administrative divisions.</p><p><b>RESULTS</b>The average ages at spermarche were 13.98 and 14.22 years old for urban and rural boys in 2005, respectively. The average ages at spermarche were 13.57 and 13.72 years old for urban and rural boys who living in southwest of China. And the average ages at spermarche were 14.18 and 14.39 years old for urban boys who lived in northwest of China, and rural boys who lived in south central of China, respectively. The average age of spermarche of the top 5 provinces were Chongqing (13.28), Guizhou (13.47), Hainan (13.47), Sichuan (13.56) and Tianjin (13.61); and the last 5 provinces were Hubei (15.30), Qinghai (15.13), Liaoning (14.75), Guangxi (14.68) and Shanghai (14.55). The average ages of spermarche were 14.43 and 14.77 years old for urban and rural boys in 1995, respectively, and thus the ages of spermarche in 2005 were 0.45 and 0.55 years earlier than that of urban and rural boys in 1995.</p><p><b>CONCLUSION</b>There was a large variation among different geographic areas. The onset of spermarche was generally earlier in urban than in rural boys, the earliest in southwest of China, and the latest in northwest and south central of China. Significant decline trend of age at spermarche could be found in Chinese boys, especially in rural areas.</p>