Nder the curve was divided into several trapezoids, and a total

The 1002 participants enrolled in the MESA Stress Study yielded a maximum of 3006 participant-days of data collection. Of these 127 days were excluded because no track-caps times were available (n=107 days), no cortisol samples were collected (n=15 days), or because there was no first cap time or reported wake-up time to use for a wake-up time (n=five days). We excluded 936 samples with no track-cap time, insufficient sample for assay, or unreliable cortisol value (0 or >100 nmol/L). Lastly we excluded those that reported Might help psychiatry the way they have advanced the study of taking oral or inhaled steroids (n=35 persons). This resulted in a total of 935 participants, 2774 days, and 15774 samples for analysis.NIH-PA Author Manuscript NIH-PA Author Manuscript NIH-PA Author Manuscript ResultsTable 1 shows selected characteristics of study participants by site, age, sex, race/ethnicity and SES indicators. The median age of the participants was 65 years. Approximately 49 of the sample was male, 20 were white, 28 black, and 53 Hispanic. Approximately 85 of participants collected at least five samples per day for all days on which they collected samples (97 of participants collected samples on all three days). The percentage of participants with at least five samples per day was similar across socio-demographic characteristics. Overall 86 of self-recorded times were within 15 minutes of the registered Track-Cap times a measure of time-recording accuracy. Younger participants, whites, and participants with higher SES showed higher percentages of time recording accuracy (p 1.64028E+14 for 16 hours were linearly interpolated based on adjacent values. Because it is a summary measure, cortisol values were not log transformed when calculating the AUC, which is in units of nmol/L*minutes. Mixed models with random intercepts (to account for within person correlations in the three daily measures) were used to model AUC as a function of SES and race/ethnicity adjusted for covariates. All times used in analyses were those registered j.addbeh.2012.10.012 by the Track-Caps device. Since participants were instructed to take their first sample when they woke up, the time of the first sample was used as the wake-up time.