Introduction
Thirdhand smoke (THS) is ultrafine particulate matter and residue resulting from tobacco combustion, with implications for health-related harm (e.g., impaired wound healing), particularly among hospitalized infants. Project aims were to characterize nicotine (THS proxy) transported on neonatal ICU (NICU) visitors and deposited on bedside furniture, as well as infant exposure.
Methods
Cross-sectional data were collected from participants in a metropolitan NICU. Participants completed a survey and CO-breath sample; and, 41.9% (n=88) of participants (N=210) were randomly selected for finger-nicotine wipes during a study phase when all bedside visitors were screened for nicotine use and finger-nicotine levels. During an overlapping study phase, 80 mother-infant dyads consented to bedside furniture-nicotine wipes and an infant-urine sample (for cotinine analyses).
Results
Most non-staff visitors’ fingers had nicotine above the limit-of-quantification (>LOQ; 61.9%). Almost all bedside furniture surfaces (93.8%) and infant cotinine measures (93.6%) had values >LOQ, regardless of household nicotine use. Participants who reported using (or lived with others who used) nicotine had greater furniture-nicotine contamination (Mdn=0.6 [IQR=0.2-1.6] µg/m 2) and higher infant cotinine (Mdn=0.09 [IQR=0.04-0.25] ng/ml), compared to participants who reported no household-member nicotine use (Mdn=0.5 [IQR=0.2-0.7] µg/m 2; Mdn=0.04 [IQR=0.03-0.07] ng/ml, respectively). Bayesian-univariate regressions supported hypotheses that increased nicotine use/exposure correlated with greater nicotine contamination (on fingers/furniture) and infant THS exposure.
Conclusions
Potential furniture-contamination pathways and infant-exposure routes (e.g., dermal) during NICU hospitalization were identified, despite hospital prohibitions on tobacco/nicotine use. This work highlights the surreptitious spread of nicotine and potential THS-related health risks to vulnerable infants during critical stages of development.
Implications
Thirdhand smoke (THS) contamination is underexplored in medical settings. Infants cared for in the neonatal intensive care unit (NICU) are vulnerable to health risks from THS exposure. This study demonstrated that 62% of non-staff NICU visitors transport nicotine on their fingers to the NICU. Over 90% of NICU (bedside) furniture was contaminated with nicotine, regardless of visitors’ reported household-member nicotine use or non-use. Over 90% of infants had detectable levels of urinary cotinine during NICU hospitalizations. Results justify further research to better protect infants from unintended THS exposure while hospitalized.