Abstract: Objective To describe the body mass index(BMI) growth trajectories from birth to 24 months old, and to examine the effect of time and quality of complementary feeding on the BMI growth trajectories. Methods A total of 1 388 eligible births were followed up from birth to 24 months old. Height and weight were measured at birth, 3, 6, 9, 12, 18 and 24 months old. The demographic data, feeding, activity and diseases data were also collected prospectively. Latent growth mixture modeling method was used to model the BMI growth trajectories. Mixed-effects Logistic regression analysis was used to examine the effect of time and quality of complementary feeding on BMI growth trajectories. Results Finally 1 255 (90.4%) children were available for study. Six BMI trajectory patterns were identified and labeled as follows:normative growth (6.5%), normal-accelerating growth (4.8%), normal-decelerating growth (28.0%), lower-persistent growth (32.9%),rapid growth (17.8%), and rapid-accelerating growth (10.0%). Taking normative growth group as reference, multivariate Logistic regression analysis indicated that introduction of complementary feeding before 6 months old could significantly increase the risk of rapid growth (OR=2.16, 95%CI:1.01-4.83) and rapid-accelerating growth (OR=3.13, 95%CI :1.35-7.25). After adjusting for confounding factors, the relationship remained significant (aOR=2.41,95%CI:1.03-5.63;aOR=3.46,95%CI:1.41-8.48). The lower feeding index score at 1 year old might significantly increase the risk of rapid growth (OR=2.50,95%CI: 1.23-5.05). This association persisted after adjustment for confounding factors (OR=2.35,95%CI:1.10-5.07). Conclusions In study area, the main BMI growth trajectory patterns include normal-decelerating growth, lower-persistent growth and rapid growth. The time and quality of complementary feeding may influence the excess weight gain during infancy.

Key words: body mass index, growth trajectories, complementary feeding, infant, birth cohort study

摘要： 目的 描述婴幼儿体重指数(BMI)生长轨迹,探讨辅食添加的时间和质量对婴幼儿BMI生长轨迹的影响。方法 采用队列研究设计,对符合纳入条件的1 388名新生儿进行随访,1岁内每三个月一次,1~2岁每半年一次,随访内容包括:体格测量、喂养、户外活动、患病等。采用潜变量增长混合模型拟合0~2岁BMI生长轨迹,运用多水平Logistic回归模型分析辅食添加对不同BMI生长轨迹的影响。结果 纳入分析的1 255名婴幼儿的BMI生长轨迹主要划分为六类:“正常平稳”(6.5%)、“正常-加速”(4.8%)、“正常-减缓”(28.0%)、“持续偏低”(32.9%)、“追赶生长”(17.8%)和“追赶生长-加速”(10.0%)。以“正常平稳”组作为参考,多水平Logistic回归模型显示:辅食添加早于6个月可显著增加“追赶生长”(OR=2.16,95%CI 1.01~4.83)和“追赶生长-加速”(OR=3.13,95%CI 1.35~7.25)模式发生的危险;调整混杂因素后,此关系仍成立(OR=2.41,95%CI 1.03~5.63;OR=3.46,95%CI 1.41~8.48)。1岁时较低的喂养指数得分可显著增加“追赶生长”(OR=2.50,95%CI 1.23~5.05)模式发生的危险;调整混杂因素后,此关系仍然成立(OR=2.35,95%CI 1.10~5.07)。结论 研究地区婴幼儿BMI生长轨迹以“正常-减缓”、“持续偏低”和“追赶生长”三种模式为主;辅食添加的时间和质量会对婴幼儿BMI生长轨迹产生影响。

关键词: 体重指数, 生长轨迹, 辅食添加, 婴幼儿, 出生队列