1 Department of Epidemiology, Graduate School of Public Health, University of Pittsburgh, Pittsburgh, Pennsylvania.
2 Department of Epidemiology and Biostatistics, College of Human Medicine, Michigan State University, East Lansing, Michigan.
J Womens Health (Larchmt). 2019 Apr;28(4):462-472. doi: 10.1089/jwh.2018.7393. Epub 2018 Dec 11.
Abdominal obesity is an important indicator of cardiometabolic dysfunction in later life. Prior studies have observed an inverse association between breastfeeding and maternal waist circumference (WC) in the years after pregnancy, but this may be due to bias resulting from systematic differences in women who do and do not breastfeed.
A total of 678 women enrolled in the Pregnancy Outcomes and Community Health (POUCH) cohort also participated in the POUCHmoms Study 7-15 years after delivery. Multivariable linear regression models and propensity scores were used to assess the relationship between WC measured at follow-up and self-reported history of breastfeeding duration of >6 months versus ≤6 months.
After a mean follow-up period of 11.0 (standard deviation = 1.4) years, breastfeeding was significantly associated with smaller WC. A threshold effect was detected for women who reported breastfeeding >6 months; their adjusted mean WC was 3.5 cm (95% confidence interval [CI]: -5.7 to -1.2) smaller compared with women who breastfed ≤6 months. The use of two propensity score approaches, weighted and matched, produced similar results; adjusted mean WC difference was -3.6 cm (95% CI: -5.6 to -1.6) and -3.1 cm (95% CI: -5.5 to -0.7), respectively.
This study extends conventional observational study methods to incorporate propensity score approaches that make it possible to separate the study design from the study analysis to account for systematic differences in women who did and did not breastfeed. After reducing potential bias, breastfeeding for greater than 6 months was independently associated with smaller WC in the decade after delivery.
腹部肥胖是晚年心脏代谢功能障碍的一个重要指标。先前的研究观察到，母乳喂养与产后数年的母亲腰围（WC）呈负相关，但这可能是由于母乳喂养和不母乳喂养的女性之间存在系统性差异，导致偏倚。
共有 678 名参加妊娠结局和社区健康（POUCH）队列的妇女也参加了产后 7-15 年的 POUCHmoms 研究。使用多变量线性回归模型和倾向评分来评估在随访时测量的 WC 与自我报告的母乳喂养时间>6 个月与≤6 个月之间的关系。
在平均 11.0 年（标准差=1.4）的随访期后，母乳喂养与 WC 较小显著相关。对于报告母乳喂养>6 个月的女性，检测到了一个阈值效应；与母乳喂养≤6 个月的女性相比，她们的调整后平均 WC 小 3.5 厘米（95%置信区间[CI]：-5.7 至-1.2）。使用两种倾向评分方法，加权和匹配，产生了相似的结果；调整后的平均 WC 差异分别为-3.6 厘米（95% CI：-5.6 至-1.6）和-3.1 厘米（95% CI：-5.5 至-0.7）。
本研究扩展了常规观察性研究方法，纳入了倾向评分方法，这使得有可能将研究设计与研究分析分开，以解释母乳喂养和不母乳喂养的女性之间的系统性差异。在减少潜在偏倚后，母乳喂养>6 个月与产后 10 年内 WC 较小独立相关。
