Background

Traffic-related air pollution (TRAP) exposure has been linked to type 2 diabetes and metabolic dysfunction in humans. Animal studies suggest that air pollutants may alter the composition of the gut microbiota, which may negatively impact metabolic health through changes in the composition and/or function of the gut microbiome.

Objectives

The primary aim of this study was to determine whether elevated TRAP exposure was correlated with gut bacterial taxa in overweight and obese adolescents from the Meta-AIR (Metabolic and Asthma Incidence Research) study. The secondary aim was to examine whether gut microbial taxa correlated with TRAP were also correlated with risk factors for type 2 diabetes (e.g., fasting glucose levels). We additionally explored whether correlations between TRAP and these metabolic risk factors could be explained by the relative abundance of these taxa.

Methods

Participants (17–19 years; n=43) were enrolled between 2014 and 2016 from Southern California. The CALINE4 line dispersion model was used to model prior year residential concentrations of nitrogen oxides (NOx) as a marker of traffic emissions. The relative abundance of fecal microbiota was characterized by 16S rRNA sequencing and spearman partial correlations were examined after adjusting for body fat percent.

Results

Freeway TRAP was correlated with decreased Bacteroidaceae (r=−0.48; p=0.001) and increased Coriobacteriaceae (r=0.48; p<0.001). These same taxa were correlated with fasting glucose levels, including Bacteroidaceae (r=−0.34; p=0.04) and Coriobacteriaceae (r=0.41; p<0.01). Further, freeway TRAP was positively correlated fasting glucose (r=0.45; p=0.004) and Bacteroidaceae and Coriobacteriaceae explained 24% and 29% of the correlation between TRAP and fasting glucose levels.

Conclusions

Increased TRAP exposure was correlated with gut microbial taxa and fasting glucose levels. Gut microbial taxa that were correlated with TRAP partially explained the correlation between TRAP and fasting glucose levels. These results suggest that exposure to air pollutants may negatively impact metabolic health via alterations in the gut microbiota.

中文翻译：

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暴露于交通相关的空气污染和超重和肥胖青少年的肠道微生物群组成

背景

与交通相关的空气污染 (TRAP) 暴露与人类的 2 型糖尿病和代谢功能障碍有关。动物研究表明，空气污染物可能会改变肠道微生物群的组成，这可能通过改变肠道微生物群的组成和/或功能对代谢健康产生负面影响。

目标

本研究的主要目的是确定来自 Meta-AIR（代谢和哮喘发病率研究）研究的超重和肥胖青少年的 TRAP 暴露升高是否与肠道细菌分类群相关。次要目的是检查与 TRAP 相关的肠道微生物类群是否也与 2 型糖尿病的危险因素（例如，空腹血糖水平）相关。我们还探讨了 TRAP 与这些代谢风险因素之间的相关性是否可以通过这些分类群的相对丰度来解释。

方法

参与者（17-19 岁；n=43）于 2014 年至 2016 年间从南加州注册。CALINE4 线扩散模型用于模拟前一年住宅中氮氧化物 (NOx) 的浓度，作为交通排放的标志。粪便微生物群的相对丰度通过 16S rRNA 测序来表征，并在调整体脂百分比后检查 spearman 偏相关性。

结果

Freeway TRAP 与减少的拟杆菌科（r=-0.48；p=0.001）和增加的科里杆菌科（r=0.48；p<0.001）相关。这些相同的分类群与空腹血糖水平相关，包括类杆菌科（r=-0.34；p=0.04）和科里杆菌科（r=0.41；p<0.01）。此外，高速公路 TRAP 与空腹血糖呈正相关（r = 0.45；p = 0.004），而拟杆菌科和Coriobacteriaceae解释了 TRAP 和空腹血糖水平之间相关性的 24% 和 29%。

结论

增加的 TRAP 暴露与肠道微生物分类群和空腹血糖水平相关。与 TRAP 相关的肠道微生物类群部分解释了 TRAP 与空腹血糖水平之间的相关性。这些结果表明，暴露于空气污染物可能会通过改变肠道菌群对代谢健康产生负面影响。