Department of Obstetrics and Gynecology, Sahlgrenska University Hospital, Gothenburg, Sweden.
Department of Obstetrics and Gynaecology, The Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden.
J Matern Fetal Neonatal Med. 2022 Dec;35(25):9014-9022. doi: 10.1080/14767058.2021.2011854. Epub 2022 Jan 3.
Prospective birth cohorts are essential for identifying associations between exposures and outcomes. However, voluntary participation introduces a potential bias due to self selection since the persons that chose to participate may differ in background characteristics and behaviors.
To investigate potential bias due to self-selection in the (NICE) birth cohort in northern Sweden.
Women in the NICE birth cohort ( = 621) were compared to nonparticipating pregnant women in Norrbotten County in northern Sweden who were eligible for participation ( = 4976) regarding maternal characteristics and lifestyle. Maternal characteristics and pregnancy outcomes were compared between the groups and associations between exposures (smoking, folic acid, BMI, parity, education) and pregnancy outcomes (birth weight and gestational age) were analyzed by linear regression analyses, examining any interaction with the group.
NICE participants were more highly educated, older and more likely to cohabit than the non-participants. They more often took folic acid and multivitamin supplements and less often smoked during early pregnancy. Pregnancy outcomes (mode of delivery, gestational age at delivery, birth weight and APGAR score) did, however, not differ significantly between participants and non-participants. Smoking, BMI, education and parity affected gestational age and birth weight, but the associations were of similar magnitude in participants and non-participants, with no significant effect on the group.
Self-selection to the NICE study was evident in some factors related to lifestyle and socioeconomic characteristics but did not appear to skew pregnancy outcomes or alter well-known effects of certain lifestyle parameters on pregnancy outcomes.
前瞻性出生队列对于确定暴露与结局之间的关联至关重要。然而，由于自愿参与会引入选择偏倚，因为选择参与的人在背景特征和行为方面可能存在差异。
调查瑞典北部 NICE 出生队列中由于自我选择而产生的潜在偏倚。
将 NICE 出生队列中的女性（ = 621）与瑞典北部诺尔兰县有资格参与但未参与的孕妇（ = 4976）进行比较，比较两组之间的母体特征和生活方式。比较两组之间的母体特征和妊娠结局，并通过线性回归分析检查暴露（吸烟、叶酸、BMI、产次、教育）与妊娠结局（出生体重和胎龄）之间的关联，同时分析与组别的交互作用。
NICE 参与者的教育程度更高、年龄更大、同居的可能性更高。与非参与者相比，他们更常服用叶酸和多种维生素补充剂，并且在孕早期吸烟的情况更少。然而，参与者和非参与者之间的分娩方式、分娩时的胎龄、出生体重和 APGAR 评分等妊娠结局并无显著差异。吸烟、BMI、教育程度和产次会影响胎龄和出生体重，但参与者和非参与者的关联幅度相似，对组别的影响无统计学意义。
NICE 研究中的自我选择在一些与生活方式和社会经济特征相关的因素中表现明显，但似乎并未影响妊娠结局，也未改变某些生活方式参数对妊娠结局的已知影响。
