Urine-sampling methods for environmental chemicals in infants and young children

Abstract

This review paper examines and evaluates urine-sampling methodologies in infants and young children, to determine which methods are suitable for use in large biomonitoring surveys or studies of environmental chemicals in children younger than 6 years. Methods for non-toilet-trained children include the use of urine bags, collection pads (e.g., cotton or gauze inserts), disposable diapers, cotton diapers, and the clean catch method. In toilet-trained children, collection methods include use of a commode insert pan as well as specimen collection cups. The advantages and disadvantages of these various methods need to be evaluated with respect to the target population, timing and frequency of collection, minimum sample volume required, method of urine extraction, potential for contamination of the sample, stability of the analyte of interest, and burden on participants and research team. Collection methods must not introduce contamination or affect the integrity of the sample, should be logistically practical, and should minimize discomfort experienced by the child. Although collection of urine samples from children who are not toilet-trained is more challenging than collection from older toilet-trained children, the vulnerability of younger children to the exposure to and health effects of environmental chemicals makes finding suitable methods a priority.

Bisphenol A concentrations in maternal breast milk and infant urine

“…In addition, among a small set of twin infants there was no correlation of urinary free or total BPA concentrations among the dyads. Given the concerns with the binding affinity and extraction recovery of the target biomarkers to the material used to collect the infant urine (Ye et al 2010), alternative collection approaches that do not require such an extraction (e.g., urine bags routinely used in hospitals) may be worth exploring (Lee and Arbuckle 2009). Although care was taken with the handling, transport and storage of the samples, it is still possible that contamination during collection or processing may have occurred or that some conjugated BPA may have reverted back to free BPA due to fluctuating temperatures (Ye et al 2007).…”

“…Studies have shown that collection and storage of biological specimens may affect biomonitoring results (Ye et al 2010; Lee and Arbuckle 2009; Calafat and Needham 2009) and field blanks were not collected in our study. Concentrations of free BPA in infant urine must be interpreted with caution because the urine was extracted from a woodpulp and cotton diaper (Ye et al 2010) and because we can’t rule out that contamination of the urine may have occurred (Völkel et al 2011).…”

Co-exposure to non-persistent organic chemicals among American pre-school aged children: A pilot study

“…Many of the biomarkers evaluated eliminate in urine after exposure to ubiquitous environmental chemicals (e.g., phthalates, parabens, bisphenol A), but exposure to or contamination with these chemicals could also occur during urine collection, particularly because of the additional provisions necessary to collect the urine from young children compared to adults (Lee and Arbuckle, 2009). To minimize external contamination during the collection and processing of the urine, the protocol was designed to avoid materials known to contain the target analytes (e.g., wipe-containing parabens) and urine was collected only after the MEC staff instructed the child’s parent/guardian regarding the proper procedures.…”

“…Compared to blood and other matrices, collecting urine is generally considered a non-invasive and relatively easy procedure, at least for adults. However, collecting urine from young children who cannot easily void in regular urine collection containers can pose logistic challenges (Lee and Arbuckle, 2009). …”

“…Blood and urine, collected during the participant’s medical examination at the mobile examination center (MEC), are also used to assess exposure to environmental chemicals (Calafat, 2012). NHANES has collected urine specimens in its MEC since 1960, but, although urine has been successfully collected from young children for other studies by using various strategies including urine bags, diapers, and commode insert pans (Lee and Arbuckle, 2009), up to 2013–2014, only participants 6 years of age and older provide urine in the MEC. Therefore, information on Americans’ exposure to environmental chemicals is more limited for children than for adults even though exposures during early childhood may be relevant to understand potential adverse effects on health later in life (US EPA, 2013).…”