Brief communication: Chronic undernutrition is associated with higher mucosal antibody levels among ariaal infants of northern kenya

Abstract

The immune activation that occurs with infection diverts energy from growth and can contribute to poor nutritional outcomes in developing infants and children. This study investigates the association between salivary immunoglobulin A (IgA) levels and growth outcomes among Ariaal infants of northern Kenya. The Ariaal are a group of settled northern Kenyan pastoralists who are under considerable nutritional stress. Two hundred and thirty-nine breastfeeding Ariaal infants were recruited into the study and underwent anthropometric measurement and saliva collection, with mothers providing individual and household characteristics for them via questionnaire. Infant saliva samples were analyzed with an ELISA for IgA in the United States. Infant anthropometric measurements were converted to height-for-age z-scores (HAZ) using the WHO Child Growth Standards. Based on multivariate models performed in SAS 9.2 two main results emerge: 1) low HAZ, an indicator of chronic undernutrition, was significantly associated with higher IgA concentration (β = -0.12, P = 0.050) and 2) boys had significantly higher IgA levels than girls (β = 0.25, P = 0.039). Although there was not a significant interactive effect between HAZ and sex, the two variables confound each other, with boys having significantly lower HAZ values than girls do. In addition, maternal breastmilk IgA was significantly associated with infant salivary IgA, indicating that maternal effects play a role in infant IgA development. Future research will unravel the three-way association between sex, stunting, and immune function in the Ariaal community.

The Immune System in Children with Malnutrition—A Systematic Review

“…The sIgA content of urine was increased or normal in severely malnourished children [60]–[61]. In mild to moderately underweight children, inconsistent results were found for sIgA in tears [63] and saliva [53]–[54] [62]–[63].…”

Dynamics of human milk nutrient composition of women from singapore with a special focus on lipids

“…A limitation of the study from Fujita et al is milk sample collection and analysis, as only foremilk was collected and milk fat was the only parameter measured to determine milk energy density (Fujita et al, ). The difference in the nutritional status between boys and girls only gets larger with time (Miller and McConnell, ). Indeed, our study was conducted in Singapore, which can be considered a nutritionally affluent society and a similar study from nutritionally stressed populations will help gain further insights on the dynamics of lactation.…”

Ecological immunity of human milk: Life history perspectives from the United States and Kenya

“…The immunological protection offered by maternal milk theoretically allows infant energy to focus on growth, not fighting infection. However, previous research in Kenya did not find a relationship between milk IgA and infant length and weight, adjusted for age (Miller & McConnell, ). There are two potential reasons that may govern this lack of relationship.…”

“…The inclusion of these covariates in both populations was based on prior work in the U.S. population that demonstrated their statistical significance with WAZ and LAZ (Miller, ), and the availability of these variables in both populations. In the Kenya population, village was also included as a covariate due to its prior significance in milk models (Miller, ; Miller & McConnell, , ). This resulted in four separate models: one LAZ model in each population and one WAZ model in each population.…”

“…These tradeoffs have been widely demonstrated. For example, Miller and McConnell () found higher levels of IgA in saliva among infants who were stunted, likely indicating a trade‐off between immune function and growth. This result has been demonstrated with other markers of immune function including a negative relationship between fecal calprotectin (a marker of gut inflammation) and infant growth indicators infants aged 1–18 months (Li et al, ); an association between growth faltering in Gambian infants and high levels of fecal neopterin, another marker of gastrointestinal inflammation (Campbell, McPhail, Lunn, Elia, & Jeffries, ); and a positive relationship between intestinal permeability (an indicator of infectious and inflammatory damage) and greater growth faltering in rural populations with endemic infections (Goto, Mascie‐Taylor, & Lunn, ; Lunn, Northropclewes, & Downes, ).…”