Table 1

Descriptive statistics of participants by study

CaPSHCSNSHDNCDS
Sample with WEMWBS and cortisol; n592105517365337
Gender; n (%) male530 (100)463 (44)809 (47)2464 (50)
Age range at cortisol measurement (years); (mean (SD))65–82
(72.8 (4.0))
60–73
(66.6 (2.7))
62–64
(63.6 (0.8))
44–46
(44.1 (0.2))
Age range at WEMWBS assessment (years); (mean (SD))73–90
(80.1 (3.9))
69–78
(73.2 (2.4))
62–64
(63.6 (0.8))
50–51
(50.7 (0.1))
Follow-up time cortisol to WEMWBS assessment (years); mean (SD)7.6 (0.4)6.6 (1.2)06.6 (0.3)
BMI (kg/m2); mean(SD)28.2 (3.8)26.9 (4.2)27.9 (4.8)27.1 (4.7)
Adult current smoking status;
n (%) smoker
53 (11.0)84 (8.1)160 (10.2)893 (18.5)
Adult social class; n (%) manual303 (59.5)400 (39)499 (29.2)1626 (34.1)
WEMWBS score; mean (SD)53.3 (10.6)51.7 (8.1)51.8 (8.0)49.5 (7.9)
Sampling times (24 hour clock); mean
Waking sample7:37N/A7:11N/A
Waking+30 mins (+45 min for NCDS)8:137:428:11
Waking+3 hour 45 minN/AN/A11:11
14:00 sample14:11N/AN/A
Evening sample22:0021:9.27N/A
Serum cortisol (nmol/L)N/A258.1 (81.2)N/AN/A
Salivary cortisol (nmol/L)
Early morning; mean (SD)19.7 (9.5)22.9 (9.6)21.3 (10.8)
Night time; median (IQR)2.3 (1.5, 3.5)2.4 (1.7,3.7)N/A
Diurnal slope (nmol/L/h); mean (SD)−1.13 (0.7)−1.43 (0.7)−4.3 (3.8)
Cortisol awakening response; mean (SD)2.3 (9.4)6.4 (11.7)N/A
Exclusions due to being on corticosteroids; n(%)62 (10%)13 (1.2%)19 (1.1%)396 (7.5)*
  • *Endocrine medication.

  • CaPS, Caerphilly Prospective Study; HCS, Hertfordshire Cohort Study; NCDS, National Child Development Study; NSHD, National Survey of Health and Development; WEMWBS, Warwick Edinburgh Mental Wellbeing Scale.