The influences of breastfeeding and infant diet in the prevention of allergy-related diseases are uncertain and many of the studies conducted on the topic are limited by methodological challenges. Our aim was to assess whether the duration of breastfeeding and age at complementary food introduction affected the prevalence of asthma, wheeze, allergic rhinoconjunctivitis (ARC) and eczema at two and six years of age. We used information gathered between 2000 and 2014 through questionnaires in the Prevention of Allergy among Children in Trondheim (PACT) study, a prospective cohort study in Trondheim, Norway. The current study includes 6802 children who submitted questionnaires detailing breastfeeding duration and or age at introduction to complementary foods, as well as at least one of the child health questionnaires completed at two and six years of age. Adjusted odds ratios (aORs) were calculated for each combination of exposure and outcomes and sensitivity analyses were performed to assess the possible influence of recall bias and reverse causality. The mean duration of breastfeeding was 11 months (SD 5.6) in this study population and 5695 of 6796 (84%) infants had been breastfed for at least 6 months. We did not find any conclusive preventative effect of longer breastfeeding on parental reported doctor-diagnosed asthma, aOR 0.79 (95% CI 0.51, 1.21). However, at 6 years of age we observed a reduction in the less strictly defined outcome wheeze, aOR 0.71 (95% CI 0.53, 0.95). Longer breastfeeding was associated with a reduced risk of ARC at 2 years, aOR 0.65 (95% CI 0.49, 0.86), with a continued protective trend at 6 years, aOR 0.77 (95% CI 0.58, 1.04). Longer breastfeeding resulted in a reduced risk of wheeze and a trend towards a protective effect on ARC up until school age. No conclusive associations were seen between the duration of breastfeeding or age at introduction to complementary foods and prevention of asthma, wheeze, ARC and eczema. The trial is registered in Current Controlled Trials as ISRCTN28090297 .

中文翻译：

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母乳喂养的持续时间、添加辅食的年龄和过敏相关疾病：一项前瞻性队列研究

母乳喂养和婴儿饮食对预防过敏相关疾病的影响尚不确定，许多关于该主题的研究都受到方法学挑战的限制。我们的目的是评估母乳喂养的持续时间和添加辅食的年龄是否会影响 2 岁和 6 岁的哮喘、喘息、过敏性鼻结膜炎 (ARC) 和湿疹的患病率。我们使用了 2000 年至 2014 年通过调查问卷收集的信息，该研究是在挪威特隆赫姆进行的一项前瞻性队列研究，即特隆赫姆儿童过敏症预防 (PACT) 研究。目前的研究包括 6802 名儿童，他们提交了详细说明母乳喂养持续时间和/或开始添加辅食的年龄的问卷，以及至少一份在 2 岁和 6 岁时完成的儿童健康问卷。针对暴露和结果的每种组合计算调整后的优势比 (aOR)，并进行敏感性分析以评估回忆偏差和反向因果关系的可能影响。在该研究人群中，母乳喂养的平均持续时间为 11 个月 (SD 5.6)，6796 名婴儿中有 5695 名 (84%) 母乳喂养至少 6 个月。我们没有发现长期母乳喂养对父母报告的医生诊断哮喘有任何决定性的预防效果，aOR 0.79 (95% CI 0.51, 1.21)。然而，在 6 岁时，我们观察到较不严格定义的结果喘鸣减少，aOR 0.71 (95% CI 0.53, 0.95)。较长时间的母乳喂养与 2 年 ARC 风险降低相关，aOR 0.65 (95% CI 0.49, 0.86)，6 年时具有持续保护趋势，aOR 0.77 (95% CI 0.58, 1.04)。更长时间的母乳喂养导致喘息风险降低，并且在学龄前对 ARC 有保护作用的趋势。母乳喂养的持续时间或添加辅食的年龄与哮喘、喘息、ARC 和湿疹的预防之间没有确定的关联。该试验在 Current Controlled Trials 中注册为 ISRCTN28090297。