School of Public Health, University College Cork, Cork, Ireland
MRC Integrative Epidemiology Unit at the University of Bristol, University of Bristol, Bristol, UK.
BMJ Open. 2023 Mar 27;13(3):e065701. doi: 10.1136/bmjopen-2022-065701.
To model trajectories of antenatal and postnatal growth using linear spline multilevel models.
Prospective cohort study.
Maternity hospital in Dublin, Ireland.
720-759 mother-child pairs from the ROLO study (initially a randomised control trial of a low glycaemic index diet in pregnancy to prevent recurrence of macrosomia [birth weight >4 kg]).
Trajectories of growth from 20 weeks gestation (abdominal circumference [AC], head circumference [HC] and weight) or birth (length/height) to 5 years.
Over 50% of women had third-level education and 90% were of white ethnicity. Women were a mean (SD) age of 32 years (4.2) at recruitment. The best fitting model for AC, HC and weight included a model with 5 linear spline periods. The best fitting models for length/height included a model with 3 linear spline periods from birth to 6 months, 6 months to 2 years and 2 years to 5 years. Comparison of observed and predicted values for each model demonstrated good model fit. For all growth measures, growth rates were generally fastest in pregnancy or immediately post partum (for length/height), with rates of growth slowing after birth and becoming slower still as infancy and childhood progressed.
We demonstrate the application of multilevel linear spline models for examining growth trajectories when both antenatal and postnatal measures of growth are available. The approach may be useful for cohort studies or randomised control trials with repeat prospective assessments of growth.
使用线性样条多层模型来构建产前和产后生长轨迹。
前瞻性队列研究。
爱尔兰都柏林的一家妇产医院。
来自 ROLO 研究的 720-759 对母婴对（最初是一项随机对照试验，研究低升糖指数饮食在妊娠中预防巨大儿复发的效果[出生体重>4kg]）。
从 20 周妊娠（腹围[AC]、头围[HC]和体重）或出生（长度/身高）到 5 岁的生长轨迹。
超过 50%的女性具有第三级教育水平，90%的女性为白种人。招募时女性的平均（SD）年龄为 32 岁（4.2）。AC、HC 和体重的最佳拟合模型包括 5 个线性样条期的模型。长度/身高的最佳拟合模型包括从出生到 6 个月、6 个月到 2 岁和 2 岁到 5 岁的 3 个线性样条期的模型。对每个模型的观察值和预测值的比较表明模型拟合良好。对于所有生长指标，生长速度在妊娠或产后立即最快（对于长度/身高），出生后生长速度减慢，随着婴儿期和儿童期的进展，生长速度变得更慢。
我们展示了多层线性样条模型在检查有产前和产后生长测量值时的应用。该方法对于具有重复前瞻性生长评估的队列研究或随机对照试验可能有用。
