Table 1.
Percent distribution of participants | Percent of participants with 5 or more samples on all daysa | Percent of samples with reported times within 15 minutes of track-caps times b | Percent of days for which 1st sample was taken within 5 minutes of wakeupc | First sample time (median) | Last sample time (median) | Difference between 1st and 2nd sample time (median) | Cortisol area under the curved (median) | |
---|---|---|---|---|---|---|---|---|
ALL SUBJECTS (N=935) | 100.0% | 85.2% | 86.0% | 78.2% | 6:42 | 22:26 | 0:34 | 6270 |
SITE | ||||||||
New York | 51.9% | 86.0% | 86.6% | 77.7% | 6:49 | 22:46 | 0:34 | 6403 |
Los Angeles | 48.1% | 84.4% | 85.1% | 78.7% | 6:36 | 22:07 | 0:35 | 6112 |
p-value e | 0.5085 | 0.0084 | 0.5146 | 0.0683 | 0.0313 | 0.5319 | 0.4893 | |
AGE | ||||||||
48–54 | 17.0% | 86.8% | 87.1% | 88.4% | 6:33 | 22:45 | 0:33 | 5562 |
55–64 | 31.1% | 85.2% | 86.9% | 77.6% | 6:32 | 22:24 | 0:34 | 6122 |
65–74 | 33.1% | 86.7% | 86.0% | 76.6% | 6:47 | 22:25 | 0:36 | 6380 |
75–89 | 18.8% | 81.3% | 82.9% | 72.8% | 6:53 | 22:23 | 0:35 | 6924 |
p-value e | 0.2638 | <.0001 | <.0001 | 0.0051 | 0.1615 | 0.3855 | 0.0003 | |
SEX | ||||||||
Female | 51.6% | 84.2% | 86.1% | 79.2% | 6:40 | 22:25 | 0:35 | 5859 |
Male | 48.5% | 86.3% | 85.7% | 77.2% | 6:45 | 22:29 | 0:34 | 6689 |
p-value e | 0.3699 | 0.5702 | 0.2027 | 0.9091 | 0.0750 | 0.0595 | 0.1030 | |
RACE | ||||||||
White | 19.6% | 85.3% | 89.1% | 86.2% | 6:45 | 22:44 | 0:33 | 7048 |
Black | 27.6% | 84.9% | 85.2% | 73.4% | 6:58 | 22:51 | 0:35 | 6300 |
Hispanic | 52.8% | 85.4% | 85.1% | 77.7% | 6:32 | 22:10 | 0:35 | 5935 |
p-value e | 0.9804 | <.0001 | <.0001 | 0.6883 | 0.1798 | 0.1514 | 0.0017 | |
TOTAL GROSS FAMILY INCOME | ||||||||
<$25,000 | 39.5% | 83.0% | 82.8% | 73.4% | 6:45 | 22:05 | 0:37 | 6152 |
$25–49,999 | 32.6% | 88.9% | 87.6% | 80.2% | 6:39 | 22:37 | 0:34 | 6208 |
>=$50,000 | 27.9% | 85.0% | 88.5% | 83.1% | 6:42 | 22:44 | 0:33 | 6543 |
p-value e | 0.3694 | <.0001 | <.0001 | 0.1008 | 0.0035 | 0.5271 | 0.8716 | |
WEALTH | ||||||||
0 Assets | 18.2% | 82.9% | 83.9% | 75.3% | 6:48 | 22:13 | 0:37 | 6167 |
1 Assets | 25.2% | 85.2% | 83.0% | 78.6% | 6:42 | 22:32 | 0:34 | 6157 |
2 Assets | 24.2% | 86.3% | 86.5% | 79.3% | 6:38 | 22:21 | 0:34 | 6219 |
3 Assets | 20.2% | 86.8% | 89.7% | 79.5% | 6:42 | 22:26 | 0:34 | 6292 |
4 Assets | 12.2% | 84.2% | 87.3% | 77.4% | 6:41 | 22:35 | 0:34 | 6696 |
p-value e | 0.5391 | <.0001 | 0.3203 | 0.0846 | 0.3911 | 0.6958 | 0.6506 | |
INCOME - WEALTH INDEX | ||||||||
0–1 points | 19.6% | 84.2% | 81.4% | 75.2% | 6:42 | 22:13 | 0:39 | 5923 |
2–3 points | 28.9% | 84.0% | 83.9% | 75.8% | 6:47 | 22:07 | 0:35 | 6105 |
4–6 points | 36.3% | 87.3% | 88.8% | 80.9% | 6:37 | 22:34 | 0:34 | 6403 |
7–8 points | 15.2% | 84.5% | 88.3% | 79.6% | 6:46 | 22:41 | 0:34 | 6682 |
p-value e | 0.5346 | <.0001 | 0.0097 | 0.0798 | 0.0542 | 0.4611 | 0.3693 | |
EDUCATION | ||||||||
<= Completed HS/GED | 48.0% | 82.6% | 83.3% | 74.8% | 6:37 | 22:06 | 0:36 | 6118 |
Some College - Associate Degree | 28.3% | 89.1% | 88.1% | 79.5% | 6:42 | 22:42 | 0:34 | 6119 |
>= Bachelor's Degree | 23.6% | 86.0% | 88.4% | 83.4% | 6:51 | 22:50 | 0:33 | 6748 |
p-value e | 0.1289 | <.0001 | <.0001 | 0.9702 | 0.0067 | 0.8616 | 0.3164 |
97% of participants had data for all three days.
Based on 15774 samples with both form and cap times.
Based on 2774 days with daily questionnaire information on whether first sample was collected at wake-up. Ninety-eight percent of days had this information on the survey to use.
The area under the curve (AUC) was calculated using the trapezoidal rule. AUC was calculated for each day and then averaged across all 3 days using time since wake up in minutes. Cortisol values were interpolated at 16 hours to ensure all participants contributed the same amount of time to the AUC measure. Only days with 3 or more samples were used. AUC is measured in units of nmol/L*minutes.
P-values are calculated using chi-square tests and anovas (age, income, and education are trend tests)