Infant's First Stool Could Inform Risk of Obesity Later in Life

Katja Korpela, MD

New data from an analysis of fecal microbiome of infants suggests bacteria in the earliest stool of an infant could help predict risk of obesity later in life.

Results of the analysis indicate infants with a greater concentration of Bacteroidetes phylum were more likely to be overweight at the 3-year follow-up.

“The concept of fetal microbiome is controversial and the colonization process after birth is better understood than the possible fetal colonization; however, there are many prenatal factors affecting the microbial composition of the baby's first stool, such as the mother's use of antibiotics during pregnancy and biodiversity of the home environment during pregnancy," said corresponding author Katja Korpela, MD, of the University of Oulu, in Finland, in a statement. "It is very interesting that the microbiome formed before birth is possibly linked to a child's subsequent weight status."

To learn more about the potential insights within the microbial composition of infant’s in early life, investigators designed their study as a prospective population-based study. Specifically, investigators sought to assess the first stool collected after birth through next-generation seeing of the 16S gene.

Patients included in the study were term and near-term infants born in the Central Finland Central Hospital in Jyväskylä, Finland. For the analysis, near-term was defined as 35 gestational weeks or more. As part of the study protocol, investigators invited the families of 312 infants born between February 3-March 13, 2014. In total, 212 infants hadfirst-pass meconium collected and had families who gave their informed consent for participation.

At the end of the 3-year follow-up period, 3-year data was available for 91 children. Follow-up data at 2 years was available for 144 infants and follow-up data at 1 year was available for 186 children. Of the children included in the study, 17% were overweight at 1 year of age, 18% were overweight at 2 years, and 19% were overweight at 3 years. Between years 1 and 3, 74% of subjects remained at normal weight states, 14 remained overweight or obese, and 16 changed from normal to overweight or obese. Additionally, 8 infants went from the overweight or obese category to the normal weight category.

Of note, infants born to mothers with gestational diabetes had a greater abundance of phylum Actinobacteria and phylum Bacteroidetes in meconium.

When examining the meconium microbiome at the phylum level, the investigators’ univariate analysis indicated the proportion of phylum Bacteroidetes was greater in the meconium of children who were overweight at 3 years (29% [SD, 22] vs 15% [SD, 22]; P=.013). Investigators also pointed out children who were overweight at 3 years also had a lower proportion of phylum Proteobacteria at birth, but this did not reach statistical significance (19% [SD, 27] vs 35% [SD, 35], P=.07).

In an analysis using machine learning, fecal microbiome at birth predicted overweight at 3 years with an area under the curve of 0.70 (SD, 0.04; P <.001). Additionally, results indicated a lower proportion of Staphylococcus at birth was associated with greater length and greater height at 1 year (ß=-.68, P=.029) and 2 years of age (β=-.74, P=.030).

Investigators highlighted the most important feature in the analysis were Bacteroides, Staphylococcus, Lactobacillus, Streptococcus, Blautia, Enterococcus, Tepidimonas and Ralstonia and families Comamonadaceae, Rikenellaceae, Bradyrhizobiaceae and Xanthomonadaceae.

Investigators noted multiple limitations within their study. These limitations included a limited sample size due to the design of the study and the inability to determine whether the observed direct pathway of the association between fecal microbiome and obesity in children.

This study, “Microbiome of the first stool and overweight at age 3 years: A prospective cohort study,” was published in Pediatric Obesity.