Feasibility of Measuring Hair Glucocorticoids as a Potential Biomarker for Chronic Stress in Older Adults With Intellectual Disabilities.

Background: Chronic stress can significantly impact health, leading to conditions such as cardiovascular disease and mental health issues. Detecting chronic stress in older adults with intellectual disabilities (ID) is challenging, but measuring scalp hair glucocorticoids (HairGC) may offer a solution. This study aims to investigate the feasibility of measuring HairGC in older adults with ID and assess reasons for failed sample collection and analysis.

Methods: Hair samples were collected in the Healthy Ageing and Intellectual Disabilities (HA-ID) cohort study (n = 278, 71.3 years [SD 6.2]). Feasibility was described as overall feasibility (percentage of successful measurements out of the total group) and quantified by consent rate (participants who consented for hair sample collection), collection rate (successfully collected hair samples from those who consented), and analysis rate (successfully analysed samples). Rates were categorised as low (< 25%), moderate (≥ 25-< 50%), good (≥ 50-< 75%) or excellent (≥ 75%), with stricter cutoffs for analysis rate (low: < 75%, moderate: ≥ 75-< 85%, good: ≥ 85-< 95%, excellent: ≥ 95%). Feasibility rates and reasons for failed collection and analysis were analysed for the total group and subgroups by age, sex and level of ID.

Results: The feasibility of consent rate (204/278; 73%), collection rate (103/204; 50%) and analysis rate (89/103; 86%) was good. Overall, HairGCs were successfully measured for 89 out of 278 participants (32%), showing a moderate overall feasibility. Reasons for collection failure (n = 101/204) were hair that was too short or too thin (n = 65, 64%), resistance (n = 9, 9%), no-shows (n = 5, 5%), other reasons (n = 9, 9%) and unknown reason (n = 13, 13%). Reasons for analysis failure (14/103) were not enough material (n = 12, 86%) and lost samples (n = 2, 14%). Overall feasibility rate was lower in males (15%) than in females (50%; p < 0.001) and higher in participants with moderate ID (42%) than in those with severe and profound ID (25%; p = 0.004).

Conclusions: Overall feasibility of measuring HairGCs in older adults with ID was moderate. Feasibility was lower in males, with insufficient hair length/thickness as the main limitation, and higher in participants with moderate ID. HairGC measurement appears most feasible in females and less so in balding males, limiting its broader applicability as a stress measurement tool in an older population.