Birungi Nancy, Fadnes Lars T, Kasangaki Arabat, Nankabirwa Victoria, Okullo Isaac, Lie Stein A, Tumwine James K, Åstrøm Anne N
Department of Clinical Dentistry, University of Bergen, Bergen, Norway.
Centre for International Health, University of Bergen, Bergen, Norway.
Community Dent Oral Epidemiol. 2017 Dec;45(6):512-521. doi: 10.1111/cdoe.12314. Epub 2017 Jun 20.
To estimate the effect of distal and proximal early life-course factors on early childhood caries (ECC) in 5-year-old Ugandan children, particularly focusing on the causal effect of exclusive breast feeding (EBF) on ECC using directed acyclic graphs (DAGs) for confounder selection.
This study had a nested prospective cohort design, focusing on 5 years of follow-ups of caregiver-children pairs from the PROMISE-EBF trial (ClinicalTrials.gov no: NCT00397150) conducted in 2011 in Eastern Uganda. Data were from recruitment interviews, 24-week, 2-year and 5-year follow-ups of a cohort of 417 mother-children pairs. Trained research assistants performed interviews with caregivers in the local language and ECC was recorded under field conditions using the World Health Organization's (WHO) decayed missing or filled teeth (dmft) index. Early life-course factors in terms of socio-demographic characteristics, EBF and other feeding habits were assessed at the various follow-ups. The outcome (ECC; dmft>0) was assessed at the 5-year follow-up. Causal diagrams as DAGs were constructed to guide the selection of confounding and collider variables to be included in or excluded from the final multivariable analysis. Negative binomial regression analyses were performed based on two comparative DAGs representing different causal models.
Model 1 based on DAG 1, showed EBF to be a protective factor against ECC, with an IRR and 95% CI of 0.62 (0.43-0.91). According to Model 2 based on DAG 2, EBF and having both parents living together had protective effects: the corresponding IRRs and 95% CI were 0.60 (0.41-0.88) and 0.48 (0.25-0.90), respectively.
Both plausible models indicated that being exclusively breastfed for 24 weeks had a protective causal effect against ECC. Further research, examining the unmeasured variables included in the DAGs is necessary to strengthen the present finding and allow stronger causal claims.
评估生命早期远端和近端因素对乌干达5岁儿童早期儿童龋（ECC）的影响，尤其关注纯母乳喂养（EBF）对ECC的因果效应，并使用有向无环图（DAG）进行混杂因素选择。
本研究采用嵌套前瞻性队列设计，重点对2011年在乌干达东部进行的PROMISE-EBF试验（ClinicalTrials.gov编号：NCT00397150）中的照顾者-儿童对进行5年随访。数据来自417对母婴队列的招募访谈、24周、2年和5年随访。训练有素的研究助理用当地语言对照顾者进行访谈，并在现场条件下使用世界卫生组织（WHO）的龋失补牙（dmft）指数记录ECC情况。在不同随访中评估社会人口学特征、纯母乳喂养和其他喂养习惯等生命早期因素。在5年随访时评估结局（ECC；dmft>0）。构建作为DAG的因果图，以指导选择纳入或排除最终多变量分析的混杂和对撞变量。基于代表不同因果模型的两个比较DAG进行负二项回归分析。
基于DAG 1的模型1显示，纯母乳喂养是预防ECC的保护因素，IRR和95%CI为0.62（0.43 - 0.91）。根据基于DAG 2的模型2，纯母乳喂养和父母双方共同生活有保护作用：相应的IRR和95%CI分别为0.60（0.41 - 0.88）和0.48（0.25 - 0.90）。
两个合理模型均表明，纯母乳喂养24周对ECC有保护性因果效应。有必要进一步研究，检查DAG中未测量的变量，以加强目前的发现并得出更强有力的因果关系结论。
