BACKGROUND Breastfeeding contributes to gastrointestinal microbiota colonization in early life, but its long-term impact is inconclusive. We aimed to evaluate whether the type of feeding during the first six months of life was associated with oral microbiota in adolescence. METHODS This is a cross-sectional sub-study using baseline information of 423 adolescents from the Finnish Health in Teens (Fin-HIT) cohort. Type of feeding was recalled by parents and dichotomized as (i) No infant formula; (ii) Infant formula (breastmilk + formula or only formula). Saliva microbiota was analysed using 16S rRNA (V3-V4) sequencing. Alpha diversity and beta diversity were compared between feeding type groups using ANCOVA and PERMANOVA, respectively. Differential bacteria abundance was tested using appropriate general linear models. RESULTS Mean age and body mass index were 11.7 years and 18.0 kg/m2, respectively. The No formula group contained 41% of the participants. Firmicutes (51.0%), Bacteroidetes (19.1%), and Proteobacteria (16.3%) were the most abundant phyla among all participants. Alpha and beta diversity indices did not differ between the two feeding groups. Three Operational Taxonomic Units (OTUs) belonging to Eubacteria and Veillonella genera (phylum Firmicutes) were more abundant in the No formula than in the Infant formula group (log2fold changes/ p - values - 0.920/ < 0.001, - 0.328/ 0.001, - 0.577/ 0.004). CONCLUSION Differences exist in abundances of some OTUs in adolescence according to feeding type during the first six months of life, but our findings do not support diversity and overall oral microbiota composition in adolescents being affected by early feeding type.

中文翻译：

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母乳喂养可能对口腔微生物群产生长期影响：Fin-HIT 队列的结果。


背景母乳喂养有助于生命早期胃肠道微生物群定植，但其长期影响尚无定论。我们的目的是评估生命前六个月的喂养类型是否与青春期的口腔微生物群相关。方法 这是一项横断面子研究，使用来自芬兰青少年健康 (Fin-HIT) 队列的 423 名青少年的基线信息。父母回忆起喂养类型并将其分为两类：（i）没有婴儿配方奶粉； (ii) 婴儿配方奶粉（母乳+配方奶或仅配方奶）。使用 16S rRNA (V3-V4) 测序分析唾液微生物群。分别使用ANCOVA和PERMANOVA比较喂养类型组之间的α多样性和β多样性。使用适当的一般线性模型测试差异细菌丰度。结果 平均年龄和体重指数分别为 11.7 岁和 18.0 kg/m2。无配方组占 41% 的参与者。厚壁菌门（51.0%）、拟杆菌门（19.1%）和变形菌门（16.3%）是所有参与者中最丰富的门。两个喂养组之间的α和β多样性指数没有差异。属于真细菌和韦荣球菌属（厚壁菌门）的三个操作分类单位 (OTU) 在无配方奶粉中比婴儿配方奶粉组更丰富（log2 倍变化/ p - 值 - 0.920/ < 0.001，- 0.328/ 0.001，- 0.577 / 0.004）。结论 根据生命前六个月的喂养类型，青春期一些 OTU 的丰度存在差异，但我们的研究结果并不支持受早期喂养类型影响的青少年的多样性和总体口腔微生物群组成。