Prevalence Of Undernutrition,overweight And Obesity Among Tibetan Adolescents Aged 12-18 Years

BackgroundDue to the restrictions of the plateau environment,the reactive backwardness of economic development in Tibet,and lack of nutrients and the shortage of medical education awareness,the nutritional level of people in Tibet is at a low level.The growth and development of children and adolescents who live in high altitude areas for long time may be significantly affected.According to the reports on the physical fitness and health research of Chinese school students,the detection prevalence of undernutrition among Tibetan students aged 7-18 years increased from 14.1%in 2005 to 19.6%in 2010 and then decreased to 13.3%in 2014,but it was still high in the 31 provinces across the country.Undernutrition among boys and girls in 31 is still high especially in the western provinces.Undemutrition also has an important impact on the health of children and adolescents,for example reducing children and adolescents'resistance and increase the risk of infection.With the support of the country economy and the gradual improvement of medical education,the physical fitness and nutritional levels of the Tibetans have changed significantly in Tibet.The proportions of overweight and obesity among children and adolescents in Tibet are increasing.According to the reports on the physical fitness and health research of Chinese school students,the prevalence of overweight and obesity among Tibetan children and adolescents aged 7-18 years showed an increasing trend,from 1.01%and 0.42%,respectively,in 1991 to 9.39%and 6.95%in 2014,respectively.It can be seen that the overweight and obesity of Tibetan children and adolescents in western China are on the rise.Overweight and obesity in children and adolescents can track into adulthood.Overweight and obesity in childhood increase not only the risk of obesity in adulthood,but it is also associated with an increased risk of stroke,coronary heart disease,hypertension and other cardiovascular diseases in adulthood.Therefore,early identification of Tibetan children and adolescents with undernutrition,overweight and obesity,and the adoption of scientific and reasonable prevention and control measures,are of great significance for the dual burden of undernutrition and overnutrition in Tibet.However,regarding the current situation of malnutrition and overweight and obesity among Tibetan children and adolescents in China,literature review shows that the latest data has only been updated to 2014,and the current epidemic status is still unclear.In addition,previous studies have shown that children and adolescents in high-altitude areas are lighter in weight and lower in height than those in low-altitude areas,but there are relatively few studies on the influence of altitude changes on the nutritional status of Tibetan children and adolescents.Based on Tibetan 3143 adolescents aged 12-18 years in Rikaze area,this study aims to describe the prevalence of adolescent undernutrition,overweight and obesity according to four screening criteria based on body mass index(BMI)(Industry criteria,Chinese criteria,IOTF criteria and WHO criteria),to assess the consistency between the four criteria,and to test trend in prevalence of undernutrition,overweight and obesity across different altitudes.Objectives1.To describe the prevalence of undernutrition,overweight and obesity among 3143 Tibetan adolescents aged 12-18 years in Tibet based on four BMI screening criteria(Industry criteria,Chinese criteria,IOTF criteria and WHO criteria).2.To assess the consistency of undernutrition,overweight and obesity between the four BMI criteria among Tibetan adolescents in Tibet.3.To explore the trends in prevalence of undernutrition,overweight and obesity across different altitudes among Tibetan adolescents in Tibet.Subjects and methods1.Using a stratified,randomized cluster-sampling method,one cross-sectional survey was conducted in Rikaze region in Tibet from August to September 2018,a total of 3 junior high schools and 3 high school schools were selected in Rikaze region in Tibet.Only participants with Tibetan nationality were included-A total of 3143 adolescents aged 12-18 years were included,including 1412 boys(44.9%).2.Anthropometric measurements included weight and height(accurate to 0.1 kg for weight and 0.1 cm for height),which were measured twice and the averaged values were used for analyses.BMI was calculated based weight and height.Four screening criteria based on BMI were used to determine undernutrition,overweight,and obesity.Three spots(Yadong county:3400 m,Sangzhuzi district:4000 m,Gangba county:4700 m)were selected based on different altitudes.3.Data was entered using EpiData3.0 software,and data entry was performed using the double entry method and logical checking.The categorical variables were presented as n(%),while the continuous variables were expressed as mean± standard deviation.T-test was used to compare difference in continuous variables between two groups.Kappa values were calculated to assess the consistency of four BMI screening criteria.Multivariate regression analysis was used to examine the trends of Tibetan junior high school in BMI across three different altitudes.Trend chi-square test was to examine the trends in prevalence of undernutrition and overnutrition of Tibetan junior high school across three different altitudes.P<0.05 indicates the statistical significance.Results1 Characteristics of the participantsIn this study,3143 Tibetan adolescents aged 12-18 years(male students:1412,44.9%)were included.The average height values among male students were higher than that among female students,and averaged BMI values among male students were lower than that among female students.Except for the 12-year-old age group,mean BMI values of boys in all age groups were lower than that of girls,and the differences were statistically significant(P<0.01).2 Prevalence of undernutrition,overweight and obesity among Tibetan adolescents aged 12-18 based on four BMI criteriaThe prevalence of undernutrition among Tibetan adolescents aged 12-18 years in Tibet was still much high based on each of three BMI criteria.Larger difference was found in prevalence of undernutrition based on each three criteria(Industry criteria:9.4%,IOTF criteria:14.7%,and WHO criteria:2.9%).The prevalence of severe wasting was 1.7%,1.8%,and 0.1%,respectively;and the prevalence of mild wasting was 7.7%,12.8%,and 2.8%,respectively.Compared with girls,the prevalence of undernutrition in boys was higher.The prevalence of overweight and obesity among Tibetan adolescents aged 12-18 years in Tibet still was relatively low based on each of four BMI criteria.Slight difference was found in prevalence of overweight based on four criteria(Chinese criteria:6.6%,Industry criteria:5.6%,IOTF criteria:4.3%,WHO criteria:5.7%).The prevalence of obesity using Industry criteria was similar with Chinese criteria(1.5%vs.1.4%),followed by WHO criteria(0.9%)and IOTF criteria(0.6%).Compared with male students,the prevalence of overweight was higher in female students.There was no significant difference in the prevalence of obesity between male students and female students(P>0.05).3 Assessment of the consistency of four BMI criteria for determining undernutrition,overweight and obesity among Tibetan adolescents aged 12-18For the consistency of the prevalence of undemutrition among Tibetan adolescents aged 12-18 based on the three BMI criteria:weighted kappa value for Industry criteria and IOTF criteria was 0.74.Kappa values for Industry criteria and WHO criteria,and the weighted kappa values of IOTF criteria and WHO criteria were all less than 0.6,which shows that the consistency between WHO criteria and other two criteria is poor.Weighted kappa value for Industry criteria and IOTF criteria was 0.74,which indicates that there is a largely high degree of consistency between industry criteria and IOTF criteria.For the consistent of prevalence of overweight and obesity among Tibetan adolescents aged 12-18 based on the four BMI criteria:The Kappa values of the prevalence of overweight and obesity among Tibetan adolescents based on four criteria in males and females were consistent in all age groups.4 Trends in prevalence of nutritional status of Tibetan adolescents across different altitudesIn this study,there was a download trend Tibetan student from junior high schools in BMI across three different altitudes(Ptrend<0.05).Based on the four BMI criteria,the detection prevalence of overweight and obesity also showed a downward trend with increase of altitude(Ptrend<0.001).Based on three BMI criteria,the detection prevalence of undernutrition showed an slightly upward trend with increase of altitude(Ptrend?0.05).Conclusion1.No matter what BMI criteria was used,Tibetan adolescents aged 12-18 years in Rikaze area faced a double burden of nutritional problems.The undernutrntion in boys was more serious than girls,while the overweight among girls was higher than boys.2.The consistency of detection prevalence of undernutrition among Tibetan adolescents was largely high between Industry criteria and IOTF criteria;the consistency of detection prevalence of overweight and obesity among Tibetan adolescents was high among Chinese criteria,Industry criteria,IOTF criteria and WHO criteria.3.With the increase of altitude,the prevalence of overweight(including obesity)greatly increased.