Watery diarrhea in early childhood and neuro-cognitive development: longitudinal follow-up study in Bangladesh.

INTRODUCTION: Globally, diarrheal disease is the third leading cause of under-five child mortality. Early-life diarrhea may adversely affect neurodevelopment through nutrient loss, environmental enteropathy, and inflammation; however, longitudinal evidence remains limited. We investigate the relationship between watery diarrhea and neurocognitive development among children under 2 years old in rural Mirzapur, Bangladesh. METHODS: In this prospective longitudinal study, 138 children aged <24 months presenting with WD were enrolled. Neurodevelopment was assessed using the Bayley Scales of Infant and Toddler Development-4 at 2 days post-recovery and at 90 days follow-up. Associations between developmental scores (cognitive, language, motor) and diarrheal duration, severity, hospitalization, anthropometry, hygiene practices, home stimulation, and socioeconomic factors were examined using multivariable linear regression models. RESULTS: The mean age of participants was 10.8 ± 5.9 months, and 60.9% were male. Median diarrheal duration was 176 h (IQR: 120-238). At baseline, mean (±SD) cognitive, language, and motor scores were 97.3 ± 11.0, 97.9 ± 11.5, and 103.8 ± 11.5, respectively. In adjusted analyses, boys consistently demonstrated significantly higher language scores than girls. Children's age and greater home stimulation were significantly associated with higher cognitive and motor scores soon after recovery, with sustained effects for cognition and language at 90 days. Diarrheal duration >72 h and lower height-for-age z-scores in Pediatrics were significantly associated with poorer language development, while hospitalization was associated with reduced motor scores shortly after recovery; however, these effects improved by 90 days. Improved handwashing practices were associated with higher language and motor scores at follow-up. CONCLUSION: Watery diarrhea in early childhood was associated with short-term impairments in neurodevelopment, particularly in language and motor domains, with partial recovery by 90 days. Child sex and age, diarrheal duration, hospitalization, caregiving environment, and hygiene practices influenced recovery. Integrated interventions addressing both diarrhea and the post-diarrheal caregiving environment are essential to support early child development.