Table 1.

Sample characteristics and their association with hair cortisol and cortisone.

Characteristic	Mean(SD)/N(%)	Cortisol M(IQR)	Cortisone M(IQR)
Sex
Male	77 (31%)	2.01 (2.36)	6.54 (5.50)
Female	172 (69%)	1.93 (2.01)	5.87 (4.80)
Age (in years)	36.13 (19.33)
Abuse	1.57 (0.42)
Neglect	1.83 (0.52)
BMI	23.95 (5.40)
Medication use
Yes	98 (39%)	2.37 (2.93)	7.16 (6.61)
No	150 (60%)	1.82 (1.99)*	5.84 (3.77)*
Ethnicity
Northern European	242 (97%)	1.99 (2.15)	6.10 (4.78)
Other	7 (3%)	2.68 (1.81)	7.90 (6.33)
Hair color
Black	3 (2%)	1.65 (2.47)	5.18 (11.31)
Brown	70 (28%)	2.18 (2.21)	6.18 (5.55)
Blond (ref)	155 (62%)	1.92 (2.07)	6.06 (4.36)
Red	10 (4%)	1.54 (4.46)	5.54 (16.64)
Grey	10 (4%)	3.10 (8.95)*	10.39 (19.82)*
No hair treatment (last 3 months)	166 (67%)	1.87 (2.11)	6.20 (4.69)
Hair dyed	72 (29%)	2.27 (2.25)	5.87 (5.23)
Hair bleached	33 (13%)	2.91 (2.89)	6.78 (6.48)
Hair permed	5 (2%)	2.69 (0.86)	5.55 (2.55)
Hair washing frequency
< 3/week	104 (42%)	1.92 (2.56)	5.86 (4.13)
≥3/week	144 (58%)	2.05 (1.84)	6.73 (5.03)
Last hair wash
≤24 h before sampling	137 (55%)	1.88 (2.20)	6.21 (5.09)
> 24 h before sampling	111 (45%)	2.17 (2.03)	6.16 (4.39)
Use of hair styling products on day of sampling
Yes	117 (47%)	2.21 (2.20)	6.49 (5.30)
No	130 (52%)	1.83 (1.78)	6.05 (4.38)
Season represented in hair sample
Winter	49 (20%)	1.81 (2.40)	6.35 (3.21)
Spring	87 (35%)	1.92 (2.20)*	6.05 (5.36)
Summer (ref)	47 (19%)	2.70 (3.09)	6.26 (5.45)
Fall	66 (27%)	1.86 (1.58)*	6.03 (5.32)

Ns may vary due to missing data. For continuous variables, means and standard deviations (SD) are reported. Conversely, for categorical data, Ns and percentages are reported. For categorical data, cortisol and cortisone levels are presented as median (M) and interquartile ranges (IQR) of each group.