| ObjectivesTo know the growth state of children and adolescents'growth and development in different ages, and find the the fastest period of growth. To study dietary intake, physical activity and other factors impacting on children and adolescents' growth and development. To provide scientific evidences for improving research on children and adolescents' growth and development in minority area in Western China.MethodsA total of 733 children and adolescents were randomly selected, aged 7 to 18 years in A_Ba County, Sichuan Province. In baseline and final investigations, general information, continue three days dietary intake, physical activity investigations were collected by questionnaire, and the physical development and state of secondary sexual characteristics were examined, respectively. Body composition was measured by bioelectrical impedance, bone mineral content (BMC) and bone area (BA) of distal forearm 1/10, proximal forearm 1/3 were measured by Dual Energy X ray Absorp-tiometry (DXA), respectively. T-test, chi-square test and Wilcoxon were taken to analyze the differences between two groups. Spearman correlation, covariance and multiple regression equations were taken to analyze the influencing factors of growth and development.Results1. The peak growth age of physical and bone mass indicators for girls were earlier about 2 years than that of boys. The peak weight and lean body mass age for girls were earlier than that of boys, whereas the peak fat age for boys was earlier about 2 years than that of girls. The peak growth ages of growth and development indicators for Tibetan students were earlier than that of Han in the same gender, for boys, earlier 0.2 to 2.7 years, for girls earlier 0.2 to 2.0 years.2. In boys, the knee height and fat growth were fast in external genitalia and pubic hair development as stageⅠ. The growth of height, sitting height, arm length and body weight was fast in external genitalia and pubic hair development as stageⅢ, while the fastest lean body mass growth in external genitalia development as stageⅣand pubic hair development as stageⅢ. External genitalia and pubic hair develop-ment as stageⅣ, the distal and proximal forearm BMD, BMC growth fast. In girls, the growth of height, sitting height, arm length, knee height, body weight, lean body mass was fast in breast development as stageⅡand pubic hair development as stageⅠ. In breast development as stageⅢand pubic hair development as stageⅡ, the fat, the distal and proximal forearm BMD, BMC growth fast.3. The intake of energy, protein, iron, zinc and total activity intensity were all significantly positive correlation with physical growth (P<0.05). Covariance analysis after adjusting confounding factors showed that height growth in the high group of protein, iron, zinc intake and strength activity group was higher than that of other groups (P<0.05).4. The intake of protein, fat and sedentary activity time were all significantly positive correlation with fat growth (P<0.05), body weight growth was negatively related to total activity intensity and outdoor activity time (P<0.05). Covariance analysis after adjusting confounding factors showed that fat growth in the high group of fat intake was higher than that of other groups (P<0.05), for girls. For boys, body weight growth in the high group of outdoor activity time was lower than that of other groups (P<0.05). Multiple regression equations analysis showed that dietary fat was significantly correlation with fat growth (P<0.05). The body weight could increase about 0.1kg per year when the intake of fat increase lOg in average day.5. The intake of protein, calcium, activity intensity, energy consumption, physical training were all significantly positive correlation with bone mass growth (P<0.05). Covariance analysis after adjusting confounding factors showed that the distal forearm 1/10 BMC of boys and proximal forearm 1/3 BMC, BMD of girls growth in participating in physical training group were higher than that of no participation. Multiple regression equations analysis showed that dietary calcium and outdoor activities time were important influence factors, the distal forearm 1/10 BMD could increase 0.003g/cm2per year when the intake of calcium increased 100mg in average day. The distal forearm 1/10 BMC could increase 0.003g per year when out-door activities time increased 1h in average day.ConclusionsThe indicators of growth and development in children and adolescents are different between nationalities, growth and development of Tibetan tend to be a little earlier than those of Han nationality in corresponding gender and age. Dietary protein, iron, zinc and physical activity could promote the physical growth of children and adolescents. Dietary fat and sedentary activity time could promote the fat growth. Dietary calcium and physical activity are the important determinant factors of bone mass increase in children and adolescents. |
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