Department of Public Health, University of Turku and Turku University Hospital, Turku, Finland; Centre for Population Health Research, University of Turku and Turku University Hospital, Turku, Finland.
Department of Biology, University of Turku, Turku, Finland.
Environ Int. 2024 Nov;193:109093. doi: 10.1016/j.envint.2024.109093. Epub 2024 Oct 22.
Early life microbial exposure influences the composition of gut microbiota. We investigated how early life factors, and the green living environment around infants' homes, influence the development of gut microbiota during infancy by utilizing data from the Steps to Healthy Development follow-up study (the STEPS study).
The gut microbiota was analyzed at early (∼3 months, n = 959), and late infancy (∼13 months, n = 984) using 16S rRNA amplicon sequencing, and combined with residential green environment, measured as (1) Normalized Difference Vegetation Index, (2) Vegetation Cover Diversity, and (3) Naturalness Index within a 750 m radius. We compared gut microbiota diversity and composition between early and late infancy, identified significant individual and family level early life factors influencing gut microbiota, and determined the role of the residential green environment measures on gut microbiota development.
Alpha diversity (t-test, p < 0.001) and beta diversity (PERMANOVA, R = 0.095, p < 0.001) differed between early and late infancy. Birth mode was the strongest contributor to the gut microbiota community composition in early infancy (PERMANOVA, R = 0.005, p < 0.01) and the presence of siblings in late infancy (PERMANOVA, R = 0.007, p < 0.01). Residential green environment showed no association with community composition, whereas time spend outdoors did (PERMANOVA, R = 0.002, p < 0.05). Measures of greenness displayed a statistically significant association with alpha diversity during early infancy, not during late infancy (glm, p < 0.05). In adjusted analysis, the associations remained only with the Naturalness Index, where higher human impact on living environment was associated with decreased species richness (glm, Observed richness, p < 0.05).
The role of the residential green environment to the infant gut microbiota is especially important in early infancy, however, other early life factors, such as birth mode and presence of sibling, had a more significant effect on the overall community composition.
早期的微生物暴露会影响肠道微生物群的组成。我们利用来自健康发展步骤后续研究（Steps to Healthy Development follow-up study，简称 STEPS 研究）的数据，调查了早期生活因素以及婴儿家庭周围的绿色生活环境如何影响婴儿期肠道微生物群的发育。
使用 16S rRNA 扩增子测序技术，在早期（约 3 个月，n=959）和晚期婴儿期（约 13 个月，n=984）分析肠道微生物群，并结合居住的绿色环境，用以下三种方法进行测量：（1）归一化差异植被指数（Normalized Difference Vegetation Index），（2）植被覆盖多样性（Vegetation Cover Diversity），以及（3）750 米半径内的自然指数（Naturalness Index）。我们比较了早期和晚期婴儿期的肠道微生物多样性和组成，确定了影响肠道微生物群的个体和家庭水平的重要早期生活因素，并确定了居住的绿色环境措施对肠道微生物群发育的作用。
早期和晚期婴儿期的 alpha 多样性（t 检验，p<0.001）和 beta 多样性（PERMANOVA，R=0.095，p<0.001）存在差异。出生方式是早期婴儿肠道微生物群落组成的最强贡献者（PERMANOVA，R=0.005，p<0.01），而兄弟姐妹的存在是晚期婴儿肠道微生物群落组成的最强贡献者（PERMANOVA，R=0.007，p<0.01）。居住的绿色环境与群落组成没有关联，而户外活动时间有（PERMANOVA，R=0.002，p<0.05）。在早期婴儿期，绿色度测量与 alpha 多样性呈统计学显著关联，而在晚期婴儿期则没有（glm，p<0.05）。在调整分析中，仅与自然指数有关，其中生活环境受人类影响越大，物种丰富度越低（glm，Observed richness，p<0.05）。
居住的绿色环境对婴儿肠道微生物群的作用在婴儿早期尤为重要，然而，出生方式和兄弟姐妹的存在等其他早期生活因素对整体群落组成的影响更大。
