(P18-017-23) The Presence of Organochlorine Pesticides in Breast Milk and the Trajectory of Infant Growth Z-Score Throughout the First Year of Life in a Brazilian Cohort

Objectives: To investigate the association between diclorodifeniltricloroetano (DDT) and trans-nanochlor in breast milk (BM) and Brazilian infants’ growth z-scores in the first year of life.

Methods: A cohort of 68 healthy adult women and their infants was followed from 28-35 gestational weeks to 12 months postpartum. BM samples were collected between 2-50 days postpartum, and the DDT and trans-nonachlor concentrations were analyzed using gas chromatography with mass spectrometry. Concentrations of DDT and trans-nonachlor >Limit of Quantification (LOQ) were defined as presence, and concentrations ≤LOQ, as absence. Infants' anthropometric measurements were taken at 1 (n=68), 6 (n=50), and 12 (n=45) months, and weight-for-age, length-for-age, weight-for-length, and BMI-for-age z-scores were calculated according to WHO growth charts. Linear Mixed Effects (LME) models were used to investigate the association of DDT and trans-nonachlor in BM with the infants' z-scores. The following confounders were used based on the Directed Acyclic Graph: birth weight, breastfeeding status, total gestational weight gain, gestational age at birth, maternal serum leptin, maternal schooling, and pre-pregnancy BMI. P< 0.1 were considered for models with the interaction between pesticides and time, and P< 0.05 for those without interactions.

Results: DDT and trans-nonachlor were found in 57.4% (39) and  67.6% (46) of the samples. Adjusted LME models with interaction revealed a positive association of the presence of trans-nonachlor in BM with an increase in BMI-for-age (β=0.002; P=0.095) and weight-for-length z-scores over time (β=0.002, P=0.092). No associations were observed of pesticides with: BMI-for-age (DDT: β=0.0004; P=0.641), weight-for-length (DDT: β=0.001; P=0.251), weight-for-age ((DDT: β=0.0001; P=0.889 - trans-nonachlor: β=0.001; P=0.343), and length-for-age (DDT: β=0.241; P=0.209 - trans-nonachlor: β=0.119; P=0.568).

Conclusions: Infants who received BM with trans-nonachlor showed an increase in BMI-for-age and weight-for-length z-scores during the first year of life, compared to infants who received BM without trans-nonachlor detection.

Funding Sources: Carlos Chagas Filho Foundation for Research Support of Rio de Janeiro State and National Council for Scientific and Technological Development