Chinn S, Rona R J
Ann Hum Biol. 1984 Jan-Feb;11(1):1-16. doi: 10.1080/03014468400006841.
Data from 29 230 children in 22 areas in England and 6 in Scotland were used to estimate the secular trend in height of primary school children over the period 1972-1980. The children were from 15 birth cohorts, born 1961-1975. The method of analysis was selected in order to give estimates from mixed longitudinal data, in which the number of measurements differed from cohort to cohort and children with incomplete data could not be assumed to be comparable to those measured at every age. When the overall goodness-of-fit to height data of polynomials in age was examined, for children measured on 7 or 8 occasions, it was found that cubic polynomials were necessary to describe the growth of boys and girls over the age range 5.0 to 11.0 years, but that cubic and quadratic coefficients could not be interpreted for individual children. No evidence of a mid-growth spurt in height was found. Models fitted to mean heights showed that there was a secular trend of increasing height over the period studied, which was greater when estimated at age eight years than at age five. At age 8 the trend was greatest in Scottish boys, 1.5 cm per decade, and least in English girls, 0.5 cm per decade. The data do not distinguish between a trend due to earlier maturation and a trend resulting in increased adult height; further data will show whether the lack of positive trend at age five estimated from the later cohorts was due to a recent cessation of secular trend.
来自英格兰22个地区和苏格兰6个地区的29230名儿童的数据被用于估算1972年至1980年期间小学生身高的长期趋势。这些儿童来自15个出生队列，出生于1961年至1975年。分析方法的选择是为了从混合纵向数据中得出估算值，在这些数据中，不同队列的测量次数不同，且不能假定数据不完整的儿童与每个年龄段都有测量数据的儿童具有可比性。当检查年龄多项式对身高数据的总体拟合优度时，对于测量了7次或8次的儿童，发现三次多项式对于描述5.0至11.0岁年龄段男孩和女孩的生长是必要的，但对于个体儿童，三次和二次系数无法解释。未发现身高有中期生长突增的证据。拟合平均身高的模型表明，在所研究的时间段内存在身高增加的长期趋势，在8岁时估算的趋势比5岁时更大。在8岁时，苏格兰男孩的趋势最大，每十年1.5厘米，而英国女孩的趋势最小，每十年0.5厘米。这些数据无法区分是由于早熟导致的趋势还是导致成人身高增加的趋势；进一步的数据将表明，从较晚队列估算出的5岁时缺乏正向趋势是否是由于近期长期趋势的停止。
