Regional variations in gut microbiota could contribute to varying health effects in China

February 18, 2021

Nutrition researchers have noticed a connection between microbes found in the human gut and certain health conditions, like diabetes, cardiovascular disease and cancer. Pinpointing the specifics behind that connection has been a more difficult task, thanks to variations in microbial patterns that have made it hard for scientists to understand exactly how gut microbes might predict health effects in certain populations.

To better understand these inconsistencies, UNC-Chapel Hill researchers recently collaborated with UNC Charlotte and the National Institute for Nutrition and Health (NINH) in Beijing, China to study the effect that geographical differences had on microbial variations – and the results imply that regional factors may play a significant role in the diversity of gut microbiota.

Dr. Penny Gordon-Larsen

“While recent evidence suggests microbiota play an important role in health, findings are often inconsistent, particularly when comparing studies across the globe,” said Penny Gordon-Larsen, PhD, associate dean for research and Carla Smith Chamblee Distinguished Professor of global nutrition. “Most studies focus on a single geographic region; thus our understanding of regional differences in microbiota patterning is limited. We are fortunate to have access to a very large cohort from China with a wealth of data and spanning 12 provinces.”

Published in BMJ Open, the study featured work from UNC Gillings School of Global Public Health researchers, including Gordon-Larsen; postdoctoral scholar Matthew Tsilimigras, PhD; Annie Green Howard, PhD, associate professor of biostatistics; and Shufa Du, MD, PhD, associate professor of nutrition.

Dr. Matthew Tsilimigras

Dr. Annie Green Howard

Dr. Shufa Du

The study team examined data on gut microbiota collected from the China Health and Nutrition Survey (CHNS), an international collaboration between the Carolina Population Center at UNC and the NINH at the Chinese Center for Disease Control and Prevention. Previous studies have shown that urbanization plays a role in shaping microbiota, which made the data from the CHNS valuable for research in this area, as it is the only large-scale, longitudinal study of its kind in China. It samples households in both rural and urban areas across 12 provinces and three megacities. The CHNS’ urbanization index captures a wide variety of factors that change over the course of urbanization, like sanitation, transportation, access to modern markets and housing infrastructure.

The team analyzed data samples from the CHNS for variances in microbiota that could be associated with geographic region, demographic factors, lifestyle, diet and the health of participants. The factor that accounted for the largest variance in a majority of cases was geographic location.

Because of the strong regional effect on microbial variances, the study’s results suggest that geography plays a stronger role in the types of gut microbiota found in a population than other factors like diet, physical activity or level of access to sanitation infrastructure. Results also suggest that cultural traditions, lifestyles and regional habitats may play more of a role in the variances than urbanization.

“China is one of the only countries in the world where we could study this complexity, given its tremendous variation in traditional and urban lifestyles,” said Gordon-Larsen. “Given the substantial variation in gut microbiota across region, these results demonstrate how difficult it is to generalize microbiome findings across different geographic areas and how important it is to consider geographic region in population-based studies of the gut microbiome.”

Future research into these complex inter-relationships may give researchers clues to further understand disease patterns across regions and countries.

Additional members of the study team include:

• UNC Charlotte researchers Shan Sun, PhD; Michael Sioda; Farnaz Fouladi, PhD, PharmD; Anthony Fodor, PhD; and Wei Sha, PhD
• NINH researchers Huijun Wang, PhD; Jiguo Zhang, PhD; Chang Su, PhD; Zhihong Wang, PhD; and Bing Zhang, PhD

Contact the UNC Gillings School of Global Public Health communications team at sphcomm@unc.edu.