Research Center for Environment and Developmental Medical Sciences, Kyushu University, Fukuoka, Japan
Department of Pediatrics, Graduate School of Medical Sciences, Kyushu University, Fukuoka, Japan.
BMJ Open. 2021 Aug 11;11(8):e043202. doi: 10.1136/bmjopen-2020-043202.
To investigate the association between breast feeding and infant development during the first year of life using sibling comparison.
Nationwide prospective birth cohort study with sibling pair analysis.
15 regional centres that participated in the Japan Environment and Children's Study.
This study included 77 119 children (singleton, term birth and no malformation/severe diseases) whose mothers were registered between January 2011 and March 2014, including 3521 duos or trios of siblings.
The primary outcome was developmental delay at 6 and 12 months of age, assessed using the Japanese translation of the Ages and Stages Questionnaires, third edition. Multivariable regression analyses adjusted for confounders were performed to estimate the risk ratios of delay associated with any or exclusive breast feeding. Pairs of siblings discordant for statuses were selected, and conditional regression analyses were conducted with a matched cohort design.
Developmental delay was identified in 6162 (8.4%) and 10 442 (14.6%) children at 6 and 12 months of age, respectively. Any breast feeding continued until 6 months or 12 months old was associated with reduced developmental delay at 12 months of age (adjusted risk ratio (95% CI): 0.81 (0.77 to 0.85) and 0.81 (0.78 to 0.84), respectively). Furthermore, exclusive breast feeding until 3 months was associated with reduced developmental delay at 12 months of age (adjusted risk ratio, 0.86 (95% CI 0.83 to 0.90)). In sibling pair analysis, the association between any breast feeding until 12 months and reduced developmental delay at 12 months of age persisted (adjusted risk ratio, 0.64 (95% CI 0.43 to 0.93)).
The present study demonstrated the association of continuous breast feeding with reduced developmental delay at 1 year of age using sibling pair analysis, in which unmeasured confounding factors are still present but less included. This may provide an argument to promote breastfeeding continuation.
利用同胞比较研究，探讨母乳喂养与婴儿在生命第一年的发育之间的关联。
全国性前瞻性出生队列研究，采用同胞对分析。
参与日本环境与儿童研究的 15 个区域中心。
本研究纳入了 2011 年 1 月至 2014 年 3 月期间登记的 77119 名（单胎、足月出生且无畸形/严重疾病）儿童，其中包括 3521 对或 3 对同胞。
使用日本版年龄与阶段问卷（第三版）评估 6 个月和 12 个月时的发育迟缓，这是主要结局指标。进行多变量回归分析，以调整混杂因素，估计与任何或纯母乳喂养相关的发育迟缓的风险比。选择状态不一致的同胞对，并采用匹配队列设计进行条件回归分析。
6 个月和 12 个月时分别有 6162（8.4%）和 10442（14.6%）名儿童出现发育迟缓。持续母乳喂养至 6 个月或 12 个月与 12 个月时发育迟缓减少相关（调整风险比（95%CI）：0.81（0.77 至 0.85）和 0.81（0.78 至 0.84））。此外，纯母乳喂养至 3 个月与 12 个月时发育迟缓减少相关（调整风险比，0.86（95%CI 0.83 至 0.90））。在同胞对分析中，持续母乳喂养至 12 个月与 12 个月时发育迟缓减少之间的关联仍然存在（调整风险比，0.64（95%CI 0.43 至 0.93））。
本研究利用同胞对分析，证明了持续母乳喂养与 1 岁时发育迟缓减少之间存在关联，在这种情况下，仍存在但较少纳入未测量的混杂因素。这可能为促进母乳喂养的持续提供了一个论据。
