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Objective To understand and evaluate the prevalence of myopia and its trend in children and adolescents aged 7-18 years in Han ethnic group in China from 2005 to 2014,and provide evidence for the prevention of myopia.Methods The data of 2005,2010 and 2014 Chinese National Students Constitution and Health Surveys were collected.The children and adolescents with complete detection data of binoculus were selected as study subjects.The sample size of three studies were 233 108,215 319 and 212 743,respectively.The method of curve fitting was used to simulate the myopia detection increase model and analyze the gender and area specific myopia detection increase trends and characteristics from 2005 to 2014.Results The overall myopia detection rate increased gradually in the children and adolescents aged 7 to 18,which was 47.5％ in 2005,55.5％ in 2010 and 57.1％ in 2014,respectively.The increase slowed in 2014.A "parabola" shape of myopia detection increase rate was observed.Myopia detection rate increased with age before puberty and decreased with age after puberty gradually.A "cross phenomenon" of myopia detection increase was observed in boys and girls between urban and rural areas.The increase of myopia detection was mainly in urban students before puberty and in rural students after puberty.The age of myopia prevalence peak has become earlier constantly in children and adolescents aged 7-18 years from 2005 to 2014,which was 13 years old in 2005,12 years old in 2010 and 11 years old in 2014.The increase rate was about 7％.During 2005-2014,the increase rate of myopia detection gradually increased in younger students and tended to zero in older students.Conclusion The detection rate of myopia was still high in children and adolescents in China.The age of myopia prevalence peak has become earlier gradually.
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Objective To understand and evaluate the prevalence of myopia and its trend in children and adolescents aged 7-18 years in Han ethnic group in China from 2005 to 2014,and provide evidence for the prevention of myopia.Methods The data of 2005,2010 and 2014 Chinese National Students Constitution and Health Surveys were collected.The children and adolescents with complete detection data of binoculus were selected as study subjects.The sample size of three studies were 233 108,215 319 and 212 743,respectively.The method of curve fitting was used to simulate the myopia detection increase model and analyze the gender and area specific myopia detection increase trends and characteristics from 2005 to 2014.Results The overall myopia detection rate increased gradually in the children and adolescents aged 7 to 18,which was 47.5％ in 2005,55.5％ in 2010 and 57.1％ in 2014,respectively.The increase slowed in 2014.A "parabola" shape of myopia detection increase rate was observed.Myopia detection rate increased with age before puberty and decreased with age after puberty gradually.A "cross phenomenon" of myopia detection increase was observed in boys and girls between urban and rural areas.The increase of myopia detection was mainly in urban students before puberty and in rural students after puberty.The age of myopia prevalence peak has become earlier constantly in children and adolescents aged 7-18 years from 2005 to 2014,which was 13 years old in 2005,12 years old in 2010 and 11 years old in 2014.The increase rate was about 7％.During 2005-2014,the increase rate of myopia detection gradually increased in younger students and tended to zero in older students.Conclusion The detection rate of myopia was still high in children and adolescents in China.The age of myopia prevalence peak has become earlier gradually.
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OBJECTIVES: The object of this study was to determine the relationship between body mass index (BMI) and early menarche in adolescent girls in Seoul. METHODS: A retrospective study was conducted with 144 middle school students in Seoul who provided informed consent. We measured their body composition, and used the questionnaire survey method for data collection from November to December 2008. Past elemental body composition data were collected from elementary school health records of first year of middle school. RESULTS: The early menarcheal group was taller and heavier than the late menarcheal group (p<0.05 from 8-12 years old). The body fat percentage (%), BMI were higher in the early menarcheal girls than the late-menarcheal girls (p<0.05, age at 13). In the result of multiple logistic regression, the BMI at the age of 8 and 9 was associated with early menarche after adjusting for birth weight, breast feeding and age at menarche of the mother (BMI at the age of 8: p for trend=0.01, BMI at the age of 9: p for trend=0.04). An increase in BMI from 7 to 8 year was associated with early menarche after adjusting for birth weight, breast feeding, age at menarche of the mother (p for trend=0.048). CONCLUSIONS: The BMI at the age of 8 and 9 was associated with the early menarche of girls and increase in BMI from 7 to 8 year was associated with the early menarche of girls. These results suggest that BMI and increase in BMI before menarche cause early menarche. Although this study does not represent all Korean adolescent girls, it is one of the few studies that have investigated the temporal relationship between BMI and early menarche.