Site-Specific Incidence Rate of Blastocystis hominis and Its Association with Childhood Malnutrition: Findings from a Multi-Country Birth Cohort Study

In this study, we investigated the potential association between the burden of asymptomatic Blastocystis spp. (Blastocystis hominis) infection and nutritional status among children under 2 years of age using the data collected from 1,715 children from eight distinct geographic locations, including Bangladesh, Brazil, India, Peru, Tanzania, Pakistan, Nepal, and South Africa. Childhood stunting, wasting, and underweight were the outcome variables, and B. hominis infection was the exposure variable of this present study. The presence of B. hominis in nondiarrheal stools was evaluated by TaqMan Array Cards. Site-specific incidence rates were estimated using Poisson regression, and multiple generalized estimating equation was used to assess the association between the B. hominis infection and nutritional status. The site-specific incidence rates of asymptomatic B. hominis infections per 100 child-months were higher in Tanzania, Peru, and South Africa when compared with the other study sites. Moreover, in terms of site-specific association, childhood stunting was significantly associated with asymptomatic B. hominis infection in Bangladesh (odds ratio [OR]: 1.62; 95% CI: 1.26–2.08), India (OR: 1.78; 95% CI: 1.46–2.16), Nepal (OR: 2.26; 95% CI: 1.60–3.21), Peru (OR: 1.47; 95% CI: 1.26–1.71), South Africa (OR: 1.57; 95% CI: 1.35–1.83), and Tanzania (OR: 2.46; 95% CI: 2.18–2.79) sites. Wasting was associated with B. hominis in the Brazil site only (OR: 3.19; 95% CI: 1.31–7.77). On the other hand, underweight was associated in the Bangladesh (OR: 1.89; 95% CI: 1.48–2.42), Brazil (OR: 4.41; 95% CI: 1.57–12.4), Nepal (OR: 2.25; 95% CI: 1.52–3.35), and Tanzania (OR: 1.68; 95% CI: 1.42–1.99) sites. Our analysis further reveals that the presence of additional pathogens may play a pathogenic role in children who have B. hominis infection.