Socioeconomics, Not Pathogens, Responsible for Children’s Neurodevelopment

ecoli bacteria inside petri dish
ecoli bacteria inside petri dish
The investigators hypothesized that pathogens that cause diarrhea would be negatively associated with both growth and neurodevelopment.

Neurodevelopment and growth among children in an urban neighborhood in Bangladesh are correlated more with parental and socioeconomic factors than with diarrheal pathogens. These results from a prospective, longitudinal birth study were published in Clinical Infectious Diseases.

Researchers conducted a study of 250 children living in the Mirpur neighborhood of Dhaka, where open sewers flow through the neighborhood. Field research assistants contacted parents twice a week to see whether their child had more than 3 unformed stools in a 24-hour period, in which case those stools were collected. Periods of diarrhea were defined as more than 3 days since last diarrheal episode.

Stool samples were assessed for 36 enteric pathogens. A psychologist assessed neurodevelopment with a culturally adjusted version of the Bayley-III Scales of Infant and Toddler Development.

A total of 228 and 210 children were followed through their first and second years of life, respectively. During year 1, members of the research team recorded 814 episodes of diarrhea (mean, 3.6 per child) and during year 2, they recorded 659 episodes (mean, 2.2 per child). Among the stool samples analyzed, an average of 4.1 pathogens were detected per sample.

The pathogens detected in year 1 were Enteroaggregative Escherichia coli (66.3%), heat-labile toxin-producing Enterotoxigenic E coli (ETEC; 32.1%), Campylobacter jejuni/coli (31.9%), heat-stable toxin-producing ETEC (31.2%), and typical Enteropathogenic E coli (23.6%). During year 2, enteroaggregative Escherichia coli remained the most prevalent (67.8%) followed by Campylobacter jejuni/coli (48.6%), Shigella species (41.4%), heat-stable toxin-producing ETEC (40.3%), and heat-labile toxin-producing ETEC (38.3%).

At 24 months, length-for-age Z score (LAZ) was positively associated with fraction of norovirus per episode, baseline LAZ, maternal weight, maternal height, and household income and negatively associated with soluble CD14 at 18 weeks, siblings under 5 years of age, 5 or more people cohabitating, and consumption of municipal drinking water (all P ≤.05).

Among children assessed for neurodevelopmental characteristics, at 24 months the average cognitive score was 88.63±5.80, language was 93.50±7.44, and motor score was 90.65±6.12. Cognitive scores were positively associated with baseline LAZ, income, and fraction of norovirus per episode and negatively associated with siblings under 5 years of age, presence of a kitchen in the home, and fraction of sapovirus and typical Enteropathogenic E Coli per episode (all P ≤.05).

Language scores were positively associated with female gender, maternal weight, 5 or more people cohabitating, and treatment of drinking water and negatively associated with siblings under 5 years of age (all P ≤.05).

Motor scores were positively associated with baseline LAZ and maternal weight (all P ≤.05).

This study may have been limited by the small sample sizes and the fact that these children carried an average of 3.3 pathogens in nondiarrheal stool, indicating that subclinical infections may have an effect on overall growth and development.

The study authors concluded diarrheal-specific pathogens had some relationship with growth and neurodevelopment, but that socioeconomic and living conditions were more impactful.

Disclosure: An author declared affiliations with industry. Please refer to the original article for a full list of disclosures.


Donowitz JR, Drew J, Taniuchi M, et al. Diarrheal pathogens associated with growth and neurodevelopment. Clin Infect Dis. Published online January 5, 2021. doi:10.1093/cid/ciaa1938.