Komlos John, Breitfelder Ariane
Department of Economics, University of Munich, 80539 Munich, Germany.
Ann Hum Biol. 2008 Jan-Feb;35(1):11-21. doi: 10.1080/03014460701747176.
The present study estimates differences in the trend and in the age-by-height profiles of US-born non-Hispanic black and white children and adolescents born 1942-2002.
The combined NHES and NHANES data sets stratified by ethnicity and gender were used. The differences in height-for-age z-scores (HAZ) were decomposed into an age effect and a secular trend effect using a non-linear regression model.
The tempo of growth among blacks is faster than among whites. Black girls are more than 0.3sigma taller than white girls between the ages of 3 and 11. At age 9 this amounts to some 2.7 cm. White boys catch up to black boys at age 14 and white girls catch up at age 15 and are taller thereafter. At age 19 whites are only slightly taller: By 0.12sigma (0.8 cm) for boys and 0.03sigma (0.2 cm) among girls. The cumulative effect of the differences in the secular trend is considerable. Between the birth cohorts of the mid-1950s and the beginning of the new century blacks gained some 0.17sigma (girls) and 0.23sigma (boys) relative to white HAZ values.
Blacks have a faster tempo of linear growth in childhood partly on account of their nutritional habits, as girls in particular tend to have higher BMI values, and partly probably because of genetic differences.
本研究评估1942年至2002年出生的美国非西班牙裔黑人和白人儿童及青少年在生长趋势和身高年龄分布方面的差异。
使用按种族和性别分层的国家健康与营养检查调查（NHES）和国家健康与营养检查调查（NHANES）合并数据集。采用非线性回归模型将年龄别身高z评分（HAZ）的差异分解为年龄效应和长期趋势效应。
黑人的生长速度比白人快。3至11岁的黑人女孩比白人女孩高0.3个标准差以上。9岁时，这一差距约为2.7厘米。白人男孩在14岁时赶上黑人男孩，白人女孩在15岁时赶上黑人女孩，此后身高更高。19岁时，白人仅略高：男孩高0.12个标准差（0.8厘米），女孩高0.03个标准差（0.2厘米）。长期趋势差异的累积效应相当大。在20世纪50年代中期出生队列与新世纪初出生队列之间，相对于白人HAZ值，黑人女孩增加了约0.17个标准差，男孩增加了0.23个标准差。
黑人儿童期线性生长速度较快，部分原因是他们的饮食习惯，特别是女孩往往有较高的BMI值，部分原因可能是基因差异。
