. Author manuscript; available in PMC: 2016 Jun 15.

Published in final edited form as: J Occup Environ Med. 2016 Jun;58(6):542–549. doi: 10.1097/JOM.0000000000000729

TABLE 5.

Mean Values of Diurnal Cortisol Parameters by Shiftwork, Stratified by Gender: BCOPS Study 2004 to 2009

Women	Shiftwork				P^† for multiple comparisons

Model I	Day (n=48)	Afternoon (n=13)	Night (n=10)	P^*	D vs. N	A vs. N	D vs. A
AUC_G^†	5741.09±2236.76	6079.60±2400.5	7395.27±3185.9	0.150	0.053	0.199	0.655
AUC_I^§	−4793.34±7064.9	−2890.88±3833.7	−3279.81±5963.2	0.569	0.503	0.887	0.350
Slope₇^∥	−0.00334±0.0015	−0.00289±0.0014	−0.00234±0.0020	0.166	0.071	0.406	0.364
Slope₄^¶	−0.00290±0.0016	−0.00238±0.0016	−0.00165±0.0021	0.098	0.038	0.312	0.331

Model II	(n=43)	(n=12)	(n=10)

AUC_G^†	5729.51±395.9	6464.45±763.0	7612.01±822.7	0.155	0.055	0.284	0.423
AUC_I^§	−4117.78±1072.5	−3143.77±2067.3	−3160.45±2228.9	0.898	0.714	0.995	0.694
Slope₇^∥	−0.00333±0.00027	−0.00297±0.00052	−0.00229±0.00056	0.291	0.118	0.352	0.564
Slope₄^¶	−0.00283±0.00029	−0.00262±0.00057	−0.00170±0.00062	0.289	0.122	0.254	0.754

Men

Model I	Day (n=86)	Afternoon (n=93)	Night (n=69)		D vs. N	A vs. N	D vs. A

AUC_G^†	6011.74±2991.8	6333.39±3124.1	6002.82±3583.8	0.742	0.986	0.518	0.504
AUC_I^§	−5608.03±7307.0	−5193.59±7756.7	−4277.22±6813.3	0.526	0.264	0.433	0.707
Slope₇^∥	−0.00325±0.0018	−0.00325±0.0017	−0.00244±0.0019	0.006	0.005	0.004	0.998
Slope₄^¶	−0.00272±0.0018	−0.00246±0.0019	−0.00188±0.0019	0.021	0.006	0.054	0.348

Model II	(n=84)	(n=88)	(n=66)

AUC_G^‡	5863.94±394.6	6329.51±353.02	5957.87±417.1	0.648	0.879	0.487	0.406
AUC_I^§	−5878.85±902.5	−4977.73±807.4	−4718.73±954.0	0.686	0.410	0.832	0.482
Slope₇^∥	−0.00333±0.00021	−0.00312±0.00019	−0.00262±0.00022	0.073	0.031	0.075	0.494
Slope₄^¶	−0.00291±0.00022	−0.00232±0.00020	−0.00199±0.00023	0.028	0.008	0.273	0.060

Model I: unadjusted means (±SD) of diurnal cortisol parameters across shiftwork.

Model II: adjusted means (±SE) of diurnal cortisol parameters across shiftwork. Adjustment was made for demographic characteristics (age, race/ethnicity, education, marital status, and rank), lifestyle behaviors (smoking status, alcohol consumption, physical activity), and waist circumference.

Bold values indicate statistically significant results.

Overall P value comparing differences across the three shift categories.

^†

P value for pairwise differences.

^‡

AUCG: Total area under the curve (expressed as nmol/L × minute).

^§

AUCI: Area under the curve with respect to increase (expressed as nmol/L × minute).

^∥

Slope₇: Slope of fitted regression line to the diurnal samples (n=7), nmol/L/minute.

^¶

Slope₄: Slope of fitted regression line to the diurnal samples (n=4), nmol/L/minute.