Prevalence of Chronic Diseases and Alterations of Gut Microbiome in People of Ningxia China During Urbanization: An Epidemiological Survey

Abstract

The continuous development of urbanization has dramatically changed people’s living environment and lifestyle, accompanied by the increased prevalence of chronic diseases. However, there is little research on the effect of urbanization on gut microbiome in residents. Here we investigated the relation between living environment and gut microbiota in a homogenous population along an urban-rural gradient in Ningxia China. According to the degree of urbanization, the population is divided into four groups: mountainous rural (MR) represents non-urbanized areas, mountainous urban (MU) and plain rural (PR) represent preliminary urbanization, and plain urban (PU) is a representative of complete urbanization. Studies have found that with the deepening of urbanization, the prevalence of chronic diseases, such as diabetes, dyslipidemia, fatty liver, gallstones, and renal cysts, have gradually increased. The intestinal richness and diversity of the microbial community were significantly reduced in the PR and the PU groups compared with the MR and the MU groups. Based on linear discriminant analysis selection, the significantly enriched genera Faecalibacterium, Prevotella, and Pseudobutyrivibrio in the MR group gradually decreased in the MU, the PR, and the PU groups. Effect size results revealed that both residence and diet had an effect on intestinal microbiota. Our results suggested that the disparate patterns of gut microbiota composition were revealed at different levels of urbanization, providing an opportunity to understand the pathogenesis of chronic diseases and the contribution of the “rural microbiome” in potential protection against the occurrence of chronic diseases.

Impact of Air Pollution on the Composition and Diversity of Human Gut Microbiota in General and Vulnerable Populations: A Systematic Review

“…Finally, 12 articles were considered eligible to be included in the systematic review, but 2 articles were excluded for missing data. A total of 10 articles were used for the data extraction [ 36 , 37 , 38 , 39 , 40 , 41 , 42 , 43 , 44 , 45 ]. The PRISMA flow diagram in Figure 1 illustrates the search results.…”

“…The included studies (nine cross-sectional and one cohort study) were published from 2018 to 2022 [ 36 , 37 , 38 , 39 , 40 , 41 , 42 , 43 , 44 , 45 ] ( Table 2 ). Among the ten studies, two of them were conducted in America [ 39 , 45 ], seven in China [ 36 , 37 , 38 , 40 , 41 , 42 , 43 ], and one in Europe (Finland) [ 44 ], and the sample size was very variable, ranging from 21 to 6627 subjects.…”

“…Half of the air pollution studies ( n = 5; 50%) examined multiple air pollutants: PM 10 ( n = 4; 40%), PM 2.5 ( n = 7; 70%), O 3 ( n = 4; 40%), NOx ( n = 6; 60%), SO 2 ( n = 4; 40%), and CO ( n = 2; 20%) [ 36 , 38 , 39 , 41 , 43 ]. Lastly, one study analysed polycyclic aromatic hydrocarbons (PAHs) [ 44 ] and one focused on the levels of urbanization [ 40 ].…”

“…Regarding exposure time, short-term exposure (from 2 to 5 days) to air pollutants was considered in four studies [ 37 , 41 , 42 ], whereas long-term exposure (28 days to 2 years) was investigated in six studies [ 36 , 38 , 39 , 40 , 44 , 45 ]. Moreover, the methods of exposure assessments varied among studies: daily air quality index scores assigned using the monitoring data of China National Environmental Monitoring Centre [ 38 ], levels of urbanization [ 40 ], ambient monitoring station [ 41 ], real-time personal exposure [ 37 , 42 ], passive sampling devices [ 44 ], and other various modelled estimates ( n = 3) [ 36 , 43 , 45 ] were used ( Table 1 ).…”

“…Two studies reported a β-diversity measure [ 41 , 42 ] to evaluate differences in microbial abundances between multiple samples. Lastly, three studies performed linear discriminant analyses for identifying potential markers of dysbiosis associated with air pollution exposure [ 38 , 40 , 41 ]. Functional gene pathways were investigated in two studies [ 39 , 41 ].…”