Table 2.

Hair cortisol concentration (HCC) mean, standard deviation, and range values (pg/mg).

First author, publication year	Infant age (months)	HCC mean (SD)	HCC range (min-max)
Karlén et al. (2015)	12	2.6 (not informed)	0.01–4000.00
Liu et al. (2016)	9 and 12	4.3 (1.3)	not informed
Flom et al. (2017)	12	86.26 (183.63)	3.60–1530.80
Liu et al. (2017)	12	not informed	not informed
Hinnouho et al. (2019)	6–23	28.8 (21.7)	13.80–35.10
Bhopal et al. (2019)	12	not informed	not informed
Ertekin et al. (2021)	6–15	15.11 (11.53)	2.40–46.33
Tuladhar et al. (2021)	12	301.16 (1111.25)	not informed
Winebrake et al. (2022)	12	not informed	not informed
Khalil et al. (2022)	6–24	not informed	3.90–506.40
Tisborn et al. (2023)	15	not informed	not informed

* [[9], [10], [11], [12], [13], [14], [15], [16], [17], [18], [19]].