Aflatoxin exposure and child nutrition: measuring anthropometric and long-bone growth over time in Nepal

Abstract

Background: Naturally occurring aflatoxins may contribute to poor growth and nutritional statuses in children.

Objectives: We analyzed the relationship between contemporary and lagged aflatoxin exposure and 1) length-for-age z-score (LAZ); and 2) length, knee-heel length, stunting, weight-for-age z-score (WAZ), and weight-for-length z-score (WLZ).

Methods: We conducted a longitudinal birth cohort study involving 1675 mother-infant dyads in rural Nepal. Participants were repeatedly visited from pregnancy to 2 years of age (2015-2019). One blood sample was collected during pregnancy and 4 samples were collected from the children at 3, 6, 12, and 18-22 months of age to measure concentrations of aflatoxin B1 (AFB1)-lysine adduct. Multivariate linear fixed-effects and logistic models with generalized estimating equations were used to identify associations between child growth and aflatoxin exposure.

Results: AFB1-lysine adducts were detected in the majority of children (at 3 months, 80.5%; at 6 months, 75.3%; at 12 months, 81.1%; and at 18-22 months, 85.1%) and in 94.3% of pregnant women. Changes in contemporary ln child AFB1-lysine adduct concentrations were significantly associated with changes in LAZ (β, -0.05; 95% CI, -0.09 to -0.02; P = 0.003), length (β, -0.19; 95% CI, -0.29 to -0.10; P < 0.001), knee-heel length (β, -0.09; 95% CI, -0.13 to -0.05; P < 0.001), and WAZ (β, -0.04; 95% CI, -0.07 to -0.005; P = 0.022). Serum aflatoxin concentrations were associated with stunting (OR, 1.18; 95% CI, 1.05-1.32; P = 0.005). Similar results were found in the models using changes in contemporary ln AFB1 adjusted for changes in child weight, with significant associations with changes in WLZ (β, -0.07; 95% CI, -0.10 to -0.03; P < 0.001). Changes in time-lagged ln AFB1 (unadjusted and adjusted for changes in child weight) were associated with changes in length and knee-heel length.

Conclusions: Our results add to the growing body of evidence confirming chronic aflatoxin exposure and suggest that exposure is significantly correlated with various negative growth outcomes, which may vary by child weight status. This trial was registered at clinicaltrials.gov as NCT03312049.

Keywords: aflatoxin; growth; knee-heel length; length-for-age; weight; weight-for-age; weight-for-length.

FIGURE 1

Participant flowchart. During pregnancy, 1 survey was missing due to a missing upload; 3 VBDs were missing due to participants ending participation, 3 due to refusals, 3 due to severe anemia, and 2 for unknown reasons. At 3 months, 50 surveys were missing due to participants being out of the study area, 4 due to missing uploads, and 1 due to the child being gifted to another family; 5 VBDs were missing due to a child illness, 52 due to refusals, 6 due to severe anemia, 2 due to missing uploads, 2 due to insufficient blood volume, 39 due to participants being out of the study area, 12 due to SAM, 20 due to unsuccessful attempts, and 19 due to participants being unable to reschedule their visit. At 6 months, 39 surveys were missing due to participants being out of the study area, 1 due to a child illness, 1 due to a refusal, and 35 due to missing uploads; 12 VBDs were missing due to a child illness, 84 due to refusals, 2 due to severe anemia, 2 due to an insufficient blood volume, 39 due to participants being out of the study area, 32 due to SAM, 15 due to an unsuccessful attempt, and 16 due to participants being unable to reschedule their visit. At 12 months, 33 surveys were missing due to participants being out of the study area, 1 due to a refusal, and 1 due to an unexpected event; 11 VBDs were missing due to a child illness, 1 due to an unsuccessful attempt, 60 due to refusals, 2 due to severe anemia, 1 due to insufficient blood volume, 33 due to participants being out of the study area, 32 due to SAM, 1 due to an unexpected event, 2 due to participants being unavailable, and 1 for an unknown reason. At 18–22 months, 58 surveys were missing due to participants being out of the study area, 6 due to child illness, 36 due to refusals, 1 due to a missing upload, and 80 due to participants being unable to reschedule their visit; 13 VBDs were missing due to a child illness, 4 due to an unsuccessful attempt, 57 due to refusals, 3 due to severe anemia, 58 due to participants being out of the study area, 3 due to SAM, and 80 due to participants being unable to reschedule their visit. At 24–26 months, 11 anthropometry measurements were missing due to participants being out of the study area, 1 due to a refusal, and 140 due to participants being unable to reschedule their visit; 5 Ages and Stages Questionnaire measurements were missing due to participants being out of the study area and 226 due to participants being unable to reschedule their visit. Abbreviations: LTFU, loss to follow-up; SAM, severe acute malnutrition; VBD, venous blood draw.