0350 At-home Sample Collection for Measurement of Diurnal Rhythms of Urinary Cortisol and Melatonin

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Abstract Introduction Sleep- and stress-related hormones (e.g., melatonin, cortisol) can be measured from dried urine samples collected at-home and sent for laboratory testing. These measures may be used to identify patterns of circadian alignment, peak nocturnal melatonin levels as well as a cortisol awakening response. The purpose of this analysis was to describe diurnal patterns and reference ranges from a 4-timepoint serial assessment of urinary cortisol and melatonin in a large cohort of at-home self collected samples. Methods This retrospective analysis evaluated data from 3,966 individuals who used an at-home Sleep and Stress Test (Everlywell, Inc.) between September 28, 2017 and July 14, 2021. Individuals provided four urine samples according to habitual sleep patterns: upon waking (T1), two hours after waking (T2), prior to the evening meal (T3), and at bedtime (T4). Melatonin and cortisol distributions were normalized to creatinine and log transformed to approximate normal distributions to define respective reference ranges (two standard deviations above and below the log transformed mean) and reverted to original units for reporting. Results 71% (n=2,832) of users were female and mean age was 42.8 (sd=12.0) years. Mean (sd) urinary values were as follows: Cortisol: T1, 29.3 (37.9) ug/g Cr; T2, 47.2 (49.8); T3, 14.9 (36.3); T4. 8.38 (26.9). Melatonin: T1, 745 (3208) ug/g Cr; T2, 169 (1189); T3, 45 (620); T4, 155 (1701). For cortisol, only 4-5% of samples fell outside the defined reference ranges across time points. Melatonin was more variable with 23% and 15% falling outside the reference range at time points T3 and T4, respectively. A majority of individuals’ peak cortisol occurred at T2 (67.4%), and melatonin at T1 (85.2%). Conclusion This analysis demonstrates measurable physiological diurnal patterns for cortisol and melatonin using at-home self-collection for dried urine tests. This provides evidence that at-home sample collection kits using dried urine spots are a viable tool for assessing diurnal patterns of sleep and stress. Future controlled studies are needed to evaluate the utility in identifying abnormal patterns associated with shift-work or sleep disorders. Support (If Any)