Non-Nutritive Suck and Airborne Metal Exposures Among Puerto Rican Infants

Abstract

Background - Air pollution has been shown to impair fetal development. However, its effect on fetal development among ethnic minorities is less studied, in part due to lack of non-intrusive assessment methods. One possible such method is non-nutritive suck (NNS), a measure of infant’s non-nutritive sucking ability and an early index of central nervous system development.Methods - Among infants aged 0-3 months enrolled in the Center for Research on Early Childhood Exposure and Development (CRECE) cohort from 2017-2019, we examined the association between exposure to fine particulate matter (PM2.5) and its components on NNS in Puerto Rican infants. We measured NNS using a pacifier attached to a pressure transducer, allowing for real-time visualization of NNS amplitude, frequency, duration, cycles/burst, cycles/min and bursts/min. We obtained data on maternal smoking, age, residential location, and infant gender and gestational age. We linked these data to prenatal concentrations of PM2.5 and components, measured at three community monitoring sites. We used linear regression to examine the PM2.5-NNS association in single pollutant models, with change in NNS expressed per 1 µg/m3 increase for sulfur, black carbon, and PM2.5 and per 1 ng/m3 for other pollutants.Results - Among 191 infants, the average NNS amplitude and burst duration was 17.0 cmH2O and 6.19 sec, respectively. Decreased NNS amplitude was consistently and significantly associated with 9-month average exposure to sulfur (-52.3 cmH2O), zinc (-0.610 cmH2O), copper (-1.63 cmH2O), vanadium (-12.7 cmH2O), nickel (-9.18 cmH2O), and to a lesser extent lead and bromine. We found no association between NNS amplitude and PM2.5, black carbon, and other components related to soil and salt. No other NNS measure was significantly associated with any examined pollutant.Conclusions - In Puerto Rican infants, prenatal maternal exposure to zinc, copper, sulfur, vanadium, and nickel is associated with lower NNS amplitudes soon after birth.