Methods: We approached a subsample (n = 148) of mother-toddler dyads for consent to sample their hair for cortisol analysis for improving understanding of toddler chronic stress. The dyads were originally participating in a longitudinal parent study (n = 322) on understanding relationships between community resource use and child development in urban and low-income settings. The parent study dyads were originally recruited in a quota sampling fashion from Women, Infant, Children (WIC) clinics in an urban, Midwestern metropolis of the United States when the children were in utero or were less than 3 months of age. Trained data collectors obtained data from dyads approximately every 6 months, typically during home visits, and were known to the dyads either through biannual contact or through mailed flyers on study updates. Dyads were eligible to participate in the hair sampling substudy if they: a) participated in time point five of the parent study (when the toddler was between 20-24 months of age, occurring from 2016 to early 2018); b) the toddler had at least 1cm length of hair; and c) provided consent to sample hair from at least their toddler and fill out a short survey on health history and hair care practices. The parent study and hair sampling substudy received approval from the institutional review board of The Ohio State University. After obtaining consent, we sampled hair from mothers and their toddler at the end of the regularly scheduled parent study home visit. We cut approximately 150 hair shafts (about the size of an aglet, or shoelace tip) next to the skin of the posterior vertex with thinning shears to minimize the appearance of hair sampling. If mothers or their toddler had in braids, hair extensions, or weaves, we offered to sample hair from the nape of the neck instead of the posterior vertex. To help mothers visualize this sampling process, we demonstrated the process using a hair styling doll. During hair sampling on the toddler, we asked mothers to either hug their toddler or have the toddler play with the hair styling doll. We used blue painter’s tape to secure hair samples greater than 4cm length to a piece of aluminum foil and marked the location of the root end of the hair; we avoided taping over the segment of hair that was 4cm proximal to the scalp. For hair samples less than 4cm length, we placed the hair in a sealed envelope. We stored the hair samples at room temperature prior to cortisol extraction in the laboratory.
Results: There were 148 dyads who participated in time point five of the parent study and who were within the age window of participation, but 6 toddlers had insufficient hair length, so 142 dyads were eligible for hair collection and were approached. A total of 94 dyads participated in hair collection (94/142=66.2%; however two mothers refused data collection on themselves due to hairstyle concerns but consented for their child). Of the 48 dyads who did not participate, 39 dyads refused and nine dyads did not respond to hair collection solicitation or it was unknown as to why they did not participate. Poor response information from these nine dyads occurred early in the substudy and suggested that some data collectors may not have felt comfortable approaching mothers for hair collection, so one primary data collector known to the participants conducted the majority of the remaining regularly scheduled time point five home visits. The duration of the entire parent study home visit was approximately 1.5 - 2 hours; hair sampling and health survey completion took approximately 15 minutes of this time. Of the 94 dyads that participated, 40 toddlers were of Black or African American race, 47 toddlers were Caucasian, five toddlers were of unknown race, and two toddlers were other race. Approximately 87% of the dyads had a yearly household income of $30,000 or less. We sampled hair from the nape of the neck rather than the posterior vertex on 10 mothers and three children when we unable to sample from the posterior vertex. Of the 39 dyads that refused participation, the primary reason was related to concerns disrupting hair appearance (17/39 = 43.5%). Additional refusal reasons included: five mothers had concerns about collection of biomaterial, five mothers said prior to collection that the child was either fearful and/or did not want to be touched, five mothers had “other” reasons for refusal, and five mothers refused for unknown reasons. Qualitative reasons for not wanting to disturb hairstyle included include concerns of thinning hair for the adult, not wanting the child to get their first haircut, or not wanting to disrupt expensive or time-consuming weaves or braids.
Discussion: Participation rates for data collection were adequate. Collecting hair from mother-child dyads for cortisol analysis is feasible. Nurse researchers should be aware of mothers’ concern of dyad hair style and appearance, which may impact participation rates. Strategies to help improve participation is for nurse researchers to adequately train data collectors to feel comfortable soliciting participation from mothers and for sampling hair, having one primary data collector, and/or using data collectors known to the participants. Research should also be conducted to determine the reliability of sampling hair from the nape of the neck versus the posterior vertex, which may be another viable strategy to help improve participation in sampling hair for cortisol analysis in mother-toddler dyads.