中国儿童身高与体重的生长模式及简单数学模型的建立

目的 探讨中国儿童身高、体重生长规律及反映规律的简单数学模型.方法 采用"2005年九市7岁以下儿童体格发育调查"及"2005年中国学生体质与健康调研"所获得的0～18岁儿童的身高、体重数据.0～6岁身高和体重曲线采用LMS法拟合,6～18岁数据采用三次样条函数平滑修匀和修正LMS法转换.生长速度根据生长曲线修匀后获得的数值计算产生.1～10岁儿童身高和体重的简单线性模型采用修匀后生长数据建立.结果 (1)我国儿童出生身长约50 cm,3、6、12、24月龄时约61、67、76、88 cm.2～10岁身高增长较为稳定,平均每年增长约6～7 cm.约3岁半和12岁时的身高分别达到出生时2倍和3倍.2～10岁估算公式:身高(cm)=年龄(岁)×6.5+76.(2)出生体重约3.3 kg.出生后第一个3个月生长速度最快,平均每月体重增加约1.0～1.1 kg;第二个3个月减慢一半,约0.5～0.6 kg,出生后第一年的后6个月又减慢一半,约0.25～0.30 kg.约3、12、24月龄时体重达到出生时的2、3、4倍.1～6岁、7～10岁体重基本呈匀速增加,平均每年分别增长2 kg和3 kg左右.1～6岁估算公式:体重(kg)=年龄(岁)×2+8,7～10岁:体重(kg)=年龄(岁)×3+2.结论 针对临床实践的需要,总结不同年龄阶段身高、体重的增长规律,提供了0～18岁儿童身高和体重的生长速度参考值,同时对1～10岁儿童身高和体重估算公式进行修订.

General growth patterns and simple mathematic models of height and weight of Chinese children

Objective To explore the growth patterns and simple mathematic models of height and weight of Chinese children. Methods The original data had been obtained from two national representative cross-sectional surveys which were 2005 National Survey of Physical Development of Children (under 7 years of age) and 2005 Chinese National Survey on Students Constitution and Health (6-18 years). Reference curves of height and weight of children under 7 years of age was constructed by LMS method, and data of children from 6 to 18 years of age were smoothed by cubic spline function and transformed by modified LMS procedure. Growth velocity was calculated by smoothed values of height and weight. Simple linear model was fitted for children 1 to 10 years of age, for which smoothed height and weight values were used. Results (1) Birth length of Chinese children was about 50 cm, average length 61 cm, 67 cm, 76 cm and 88 cm at the 3rd, 6th, 12th and 24th month. Height gain was stable from 2 to 10 years of age, average 6-7 cm each year. Birth length doubles by 3.5 years, and triples by 12 years. The formula estimating average height of normal children aged 2-10 years was, height (cm) = age (yr)×6.5+76 (cm). (2) Birth weight was about 3.3 kg. Growth velocity was at peak about 1.0-1.1 kg/mon in the first 3 months, decreased by half and was about 0.5-0.6 kg/mon in the second 3 months, and was reduced by a quarter, which was about 0.25-0.30 kg/mon, in the last 6 months of the first year. Body mass was up to doubles, triples and quadruple of birth weight at about the 3rd, 12th and 24th month. Average annual gain was about 2 kg and 3 kg from 1-6 years and 7-10 years, respectively. The estimated formula for children 1 to 6 years of age was weight (kg)=age (yr)×2+8 (kg), but for those 7-10 years old, weight (kg)=age (yr)×3+ 2 (kg). Conclusions Growth patterns of height and weight at the different age stages were summarized for Chinese children, and simple reference data of height and weight velocity from 0 to 18 years and approximate estimation formula from 1-10 years was presented for clinical practice.