Owing to high rates of prenatal complications, twins are, on average, substantially smaller than population norms on physical measurements including height, weight, and head circumference at birth. By early childhood, twins are physically average. This study is the first to explore the process of catch-up growth by fitting asymptotic growth models to age-standardized height, weight, and head circumference measurements in a community sample of twins (n = 1281, 52.3% female) followed at up to 17 time points from birth to 15 years. Catch-up growth was rapid over the first year and plateaued around the population mean by early childhood. Shared environmental factors accounted for the majority of individual differences in initial physical size (57.7–65.5%), whereas additive genetic factors accounted for the majority of individual differences in the upper asymptotes of height, weight, and head circumference (73.4–92.6%). Both additive genetic and shared environmental factors were associated with variance in how quickly twins caught up. Gestational age and family SES emerged as important environmental correlates of physical catch-up growth.

由于产前并发症发生率较高，双胞胎出生时的身体测量数据（包括身高、体重和头围）平均显着小于正常人群。到了童年早期，双胞胎的体格就处于平均水平。这项研究首次通过将渐近生长模型与社区双胞胎样本（n  = 1281，52.3% 女性）中的年龄标准化身高、体重和头围测量结果进行拟合，探索了追赶生长的过程，随后进行了长达从出生到15岁17个时间点。第一年的追赶性增长很快，到幼儿期人口数量就趋于稳定。共同的环境因素造成了初始身体尺寸的大部分个体差异（57.7-65.5%），而加性遗传因素则造成了身高、体重和头围上渐近线的大部分个体差异（73.4-92.6%） 。加性遗传和共同的环境因素都与双胞胎赶上的速度差异有关。胎龄和家庭社会经济地位成为身体追赶性生长的重要环境相关因素。