Table 4.
Mean differences in selected cortisol curve features associated with socio-demographic characteristics before and after adjustment for compliance. Estimates are shown for cortisol values log-transformed prior to computing individual-level features (Log-cortisol units).
| Wakeup | CAR | Early Decline Slope | Late Decline Slope | AUC | ||||||
|---|---|---|---|---|---|---|---|---|---|---|
| Model 1 | Model 2 | Model 1 | Model 2 | Model 1 | Model 2 | Model 1 | Model 2 | Model 1 | Model 2 | |
| Race/ethnicity | ||||||||||
| African American | −0.23 (−0.4, −0.07) | −0.23 (−0.39, −0.06) | −0.1 (−0.26, 0.06) | −0.09 (−0.25, 0.07) | 0.12 (−0.03, 0.28) | 0.12 (−0.04, 0.28) | 0.23 (0.08, 0.38) | 0.22 (0.08, 0.37) | −0.09 (−0.26, 0.09) | −0.08 (−0.26, 0.1) |
| Hispanic | −0.23 (−0.39, −0.07) | −0.23 (−0.39, −0.07) | −0.06 (−0.22, 0.09) | −0.06 (−0.22, 0.09) | 0.20 (0.05, 0.35) | 0.20 (0.04, 0.35) | −0.21 (−0.36, −0.07) | −0.22 (−0.36, −0.07) | −0.35 (−0.52, −0.17) | −0.35 (−0.52, −0.17) |
| Gender | ||||||||||
| Male | 0.01 (−0.09, 0.12) | 0.02 (−0.09, 0.12) | −0.1 (−0.2, 0) | −0.1 (−0.2, 0.01) | 0.30 (0.2, 0.4) | 0.30 (0.2, 0.4) | −0.11 (−0.2, −0.02) | −0.11 (−0.2, −0.02) | 0.25 (0.14, 0.36) | 0.25 (0.14, 0.36) |
| Age | ||||||||||
| 55–64 | 0.15 (0, 0.31) | 0.15 (0, 0.31) | 0.04 (−0.11, 0.19) | 0.04 (−0.11, 0.19) | −0.07 (−0.21, 0.08) | −0.07 (−0.21, 0.08) | 0.04 (−0.1, 0.18) | 0.03 (−0.11, 0.17) | 0.18 (0.01, 0.35) | 0.18 (0.01, 0.34) |
| 65–74 | 0.26 (0.11, 0.41) | 0.26 (0.11, 0.41) | −0.1 (−0.24, 0.05) | −0.09 (−0.24, 0.06) | 0.02 (−0.13, 0.17) | 0.02 (−0.13, 0.16) | 0.14 (0, 0.28) | 0.14 (0, 0.28) | 0.37 (0.2, 0.54) | 0.37 (0.2, 0.53) |
| 75+ | 0.44 (0.26, 0.61) | 0.44 (0.27, 0.62) | −0.13 (−0.3, 0.05) | −0.12 (−0.29, 0.05) | 0.01 (−0.16, 0.18) | 0 (−0.17, 0.17) | 0.21 (0.05, 0.37) | 0.2 (0.05, 0.36) | 0.57 (0.38, 0.76) | 0.57 (0.38, 0.76) |
| Income | ||||||||||
| $25,000 to <$50,000 | −0.1 (−0.23, 0.02) | −0.1 (−0.23, 0.02) | 0.07 (−0.06, 0.19) | 0.06 (−0.07, 0.18) | 0.07 (−0.06, 0.19) | 0.08 (−0.05, 0.2) | −0.07 (−0.18, 0.05) | −0.06 (−0.18, 0.05) | −0.06 (−0.2, 0.08) | −0.06 (−0.2, 0.08) |
| $50,000 and higher | 0.07 (−0.08, 0.22) | 0.07 (−0.08, 0.22) | 0.05 (−0.09, 0.2) | 0.05 (−0.1, 0.19) | 0.02 (−0.12, 0.17) | 0.03 (−0.11, 0.18) | −0.16 (−0.29, −0.02) | −0.15 (−0.29, −0.02) | −0.09 (−0.25, 0.08) | −0.09 (−0.25, 0.07) |
| Education | ||||||||||
| Some college to Associate Degree | 0.08 (−0.05, 0.21) | 0.08 (−0.05, 0.21) | −0.03 (−0.16, 0.1) | −0.02 (−0.15, 0.11) | −0.15 (−0.28, −0.02) | −0.14 (−0.27, −0.01) | 0.09 (−0.03, 0.21) | 0.09 (−0.03, 0.2) | −0.07 (−0.21, 0.07) | −0.08 (−0.22, 0.06) |
| Bachelors degree or more | 0.07 (−0.09, 0.23) | 0.07 (−0.09, 0.22) | 0.01 (−0.14, 0.16) | 0.01 (−0.15, 0.16) | −0.14 (−0.29, 0.01) | −0.13 (−0.28, 0.02) | 0.16 (0.02, 0.31) | 0.16 (0.02, 0.31) | 0 (−0.17, 0.17) | −0.01 (−0.18, 0.16) |
Note: Beta coefficients represent the log relative difference in cortisol features by sociodemographic category, since cortisol levels were log-transformed prior to constructing the features. For example, African Americans have 100%*[1-exp (−0.23)]=20.5%lower wake-up cortisol than whites with adjustment for other socio-demographic features (model 1) and compliance score (model 2). Reference category for race is non-Hispanic White; for gender is female; for age is 45 to 54 years old; for income is less than or equal to $25,000/year; and for education is high school/GED or less. Model 1 is adjusted for all other socio-demographic characteristics (race/ethnicity, sex, age, income, and education). Model 2 is additionally adjusted for level of compliance. Statistically significant associations are bolded.