TABLE 1.
Overview of included cohorts
| Study | n | Age in years | BMI in kg/m2 Or BMI SDS M ± SD | % male | % obesity | HairF in pg/mg | HairE in pg/mg | HairGC analysis | Risk of bias a | Reported bivariate correlations | Reported regression coefficients |
|---|---|---|---|---|---|---|---|---|---|---|---|
| M ± SD | M ± SD | M ± SD | |||||||||
| Adult cohorts | |||||||||||
| Abdulateef et al. (2019) | 65 | 33.1 ± 10.4 | 26.4 ± 5.7 | 9.8 | 28.1 | 17.2 | ELISA | 23311 | AC | AC | |
| Abell et al. (2016) | 3,634 | 69.8 ± 5.8 | 26.7 ± 4.5 | 68.4 | 19.8 | 12.6 ± 46.4 | LC–MS | 21121 | ACD | A | |
| Aguilo et al. (2018) | 53 | 56.7 ± 12.5 | 25.1 ± 3.9 | 30.2 | 9.4 | 14.0 ± 9.0 | ELISA | 23321 | A | A | |
| Berger et al. (2019)—Cohort WPHC | 207 | 40.3 ± 16.9 | 31.5 ± 7.2 | 44.4 | 14.2 ± 27.8 | ELISA | 23331 | A | |||
| Berger et al. (2019)—Cohort YPC | 122 | 19.4 ± 3.1 | 25.2 ± 6.9 | 43.4 | 7.8 ± 9.3 | ELISA | 23331 | A | |||
| Boesch et al. (2014) | 177 | 20.1 ± 1.1 | 23.6 ± 3.1 | 100 | 358.8 ± 159.1 | ELISA | 23131 | A | |||
| Bossé et al. (2018) | 598 | 64.9 ± 6.8 | 29.3 ± 6.5 | 80.6 | 36.9 | 11.9 ± 26.7 | CLIA | 32121 | AC | AC | |
| Brianda et al. (2020) | 134 | 24.6 ± 4.4 | 7.1 | 82.3 ± 94.3 | ELISA | 23311 | A | A | |||
| Castro‐Vale et al. (2020) | 128 | 49.1 ± 15.5 | 27.0 ± 3.9 | 68 | 4.7 ± 3.7 | LC–MS | 21331 | A | A | ||
| Cedillo et al. (2020) | 62 | 29.2 ± 7.5 b | 30.0 ± 7.7 b | 0 | 27.0 | 130.7 ± 124.5 b | ELISA | 23131 | A | ||
| Chan et al. (2014) | 57 | 44.5 ± 12.5 b , c | 27.6 ± 6.8 b , c | 45.6 | 33.3 | 98.8 ± 74.8 b , c | ELISA | 33121 | AC | ||
| Chen et al. (2013) | 53 | 40.7 ± 6.6 | 22.4 ± 2.9 | 98.11 | 18.9 ± 13.6 | LC–MS | 22331 | A | |||
| Chen et al. (2015)—female adults | 75 | 43.3 ± 8.9 | 30.2 ± 5.5 | 0 | 4.6 ± 3.4 | LC–MS | 21121 | AD | |||
| Chen et al. (2015)—male adults | 10 | 41.6 ± 9.2 | 29.4 ± 1.9 | 100 | 3.1 ± 1.5 | LC–MS | 21121 | AD | |||
| Davison et al. (2019) | 344 | 25.4 ± 1.5 b c | 23.7 ± 6.3 | 43 | 4.3 ± 4.9 | 6.3 ± 5.8 | LC–MS | 11121 | AE | ||
| Dettenborn et al. (2010)—employed | 28 | 32.6 ± 9.3 | 22.6 ± 3.8 | 42.9 | 7.1 ± 3.0 | CLIA | 22321 | A | |||
| Dettenborn et al. (2010)—unemployed | 31 | 36.7 ± 11.0 | 24.6 ± 6.3 | 3.2 | 10.2 ± 7.2 | CLIA | 22321 | A | |||
| Diebig et al. (2016) | 129 | 32.3 ± 12.1 | 24.4 ± 4.3 | 24 | 11.6 ± 13.2 | CLIA | 22331 | A | A | ||
| Dowlati et al. (2010)—controls | 87 | 65.7 ± 11.1 | 27.5 ± 4.9 | 80.5 | 185.3 ± 131.6 | ELISA | 33321 | A | |||
| Enge et al. (2020) | 470 | 38.6 ± 8.9 | 24.6 ± 4.9 | 34 | 8.3 | 6.1 ± 7.4 | LC–MS | 11311 | A | A | |
| Engert et al. (2018) | 332 | 40.7 ± 9.2 | 23.6 ± 3.3 | 40.7 | 1.6 ± 1.0 | 2.5 ± 0.7 | LC–MS | 11131 | AE | ||
| Etwel et al. (2014) | 39 | 23.8 ± 6.2 | 23.2 ± 4.8 | 0 | 257.2 ± 101.8 | ELISA | 23121 | A | |||
| Feeney et al. (2020) | 1876 | 66.4 ± 8.7 | 25.6 | 31.5 | 18.8 ± 48.1 | 12.4 ± 10.3 | LC–MS | 11111 | AE | AE | |
| Feller et al. (2014) | 654 | 65.8 ± 8.4 | 27.5 ± 4.4 | 46 | 35.1 ± 32.8 | CLIA | 12111 | ACD | |||
| Fischer et al. (2017) | 139 | 50.6 ± 14.6 | 27.5 ± 6.0 | 28 | 28 | ELISA | 13311 | A | |||
| Gao et al. (2014)—adult control | 23 | 41.5 ± 12.8 | 22.9 ± 2.7 | 61 | 0 | 4.3 ± 3.9 | LC–MS | 22321 | A | ||
| Gao et al. (2014)‐ adult earthquake survivor | 20 | 45.5 ± 14.2 | 23.4 ± 2.1 | 60 | 0 | 46.3 ± 48.4 | LC–MS | 22321 | A | ||
| Garcia‐Leon et al. (2018) | 62 | 33.0 ± 3.7 | 22.8 ± 2.9 | 0 | 127.9 ± 111.5 | ELISA | 13313 | A | |||
| Gidlow et al. (2016) | 132 | 41.4 ± 11.4 | 25.1 ± 4.8 | 28.9 | 10.8 ± 9.4 | ELISA | 13321 | A | A | ||
| Grass et al. (2015)—study I | 42 | 24.8 ± 5.7 | 21.3 ± 2.9 | 52.4 | 3.5 ± 2.3 | LC–MS | 11311 | A | |||
| Grass et al. (2015)—study II | 52 | 25.0 ± 4.9 | 22.8 ± 3.2 | 57.7 | 3.2 ± 3.8 | LC–MS | 11311 | A | |||
| Henley et al. (2014) | 109 | 29.8 | 16.2 | 592.2 ± 304.8 b | ELISA | 13123 | A | A | |||
| Hollenbach et al. (2018) | 59 | 36 ± 6 | 32.2 ± 9.8 | 3.4 | 27.8 ± 30.8 | ELISA | 13321 | A | |||
| Hunter et al. (2020) | 140 | 22.8 ± 6.0 | 27.2 ± 6.6 | 0 | 29 | 11.2 ± 23.5 | LC–MS | 21321 | A | A | |
| Jackson et al. (2017) | 2,527 | 67.9 ± 7.3 | 28.2 ± 5.2 | 41 | 30.5 | 30.5 ± 76.7 | LC–MS | 11131 | |||
| Janssens et al. (2017) | 111 | 43.4 ± 10.4 | 24.4 ± 3.8 | 60 | 10.8 | 14.9 ± 9.4 c | LC–MS | 21111 | AD | AD | |
| Kozik et al. (2015) | 66 | 71.9 ± 5.8 | 25.0 ± 4.0 | 33.3 | 25.8 ± 17.2 | ELISA | 13321 | AC | |||
| Kuehl et al. (2015) | 41 | 41.2 | 23.3 ± 3.6 b | 36.6 | 14.1 | 4.3 ± 4.2 b | 19.8 ± 21.5 b | CLIA | 22121 | ACEF | ACEG |
| Lanfear et al. (2020) | 41 | 68.1 ± 5.3 | 48 | 10.5 ± 13.6 | LC–MS | 11321 | D | ||||
| Larsen et al. (2016)—fathers | 231 | 40.3 ± 5.4 | 26.2 ± 3.7 | 100 | 177.4 ± 119.2 | ELISA | 23331 | A | A | ||
| Larsen et al. (2016)—mothers | 301 | 38.0 ± 4.3 | 26.6 ± 5.4 | 0 | 146.1 ± 102.3 | ELISA | 23331 | A | A | ||
| Lehrer et al. (2020) | 141 | 45.8 ± 15.2 | 32.6 | ELISA | 13122 | D | D | ||||
| Ling et al. (2020)—mothers | 35 | 29.7 ± 5.6 | 32.4 ± 7.0 | 0 | 58.1 | 7.0 ± 8.1 | ELISA | 23111 | A | A | |
| Manenschijn et al. (2013) | 283 | 74.8 ± 7.1 c | 27.4 ± 4.0 c | 33.9 | 23.2 ± 10.1 c | ELISA | 13121 | AC | |||
| Manenschijn, Koper et al. (2011) | 46 | ELISA | 23321 | CD | |||||||
| Mazgelyte et al. (2019) | 163 | 38.5 ± 9.3 | 26.6 ± 5.3 c | 100 | 237.8 ± 160.8 c | LC–MS | 21131 | AC | AC | ||
| McLennan et al. (2016) | 246 | 42.0 ± 11.2 | 26.4 ± 5.3 | 10.2 | 23.8 | 15.1 ± 14.6 | CLIA | 22311 | A | A | |
| Menning et al. (2015)—breast cancer no chemotherapy | 33 | 52.4 ± 7.3 | 24.0 ± 3.8 | 0 | 23.8 ± 16.6 | ELISA | 33331 | A | |||
| Menning et al. (2015)—controls | 38 | 50.1 ± 8.7 | 24.5 ± 3.5 | 0 | 27.0 ± 13.7 | ELISA | 23331 | A | |||
| Menning et al. (2015)—breast cancer chemotherapy | 32 | 50.2 ± 9.2 | 25.8 ± 4.5 | 0 | 33.4 ± 26.2 | ELISA | 33331 | A | |||
| Michaud et al. (2016) | 675 | 52.0 ± 15.2 | 28.2 ± 5.8 | 36.1 | 278.2 ± 553.8 | ELISA | 13331 | A | A | ||
| Mwanza et al. (2016) | 473 | 19.3 ± 1.4 | 31.4 ± 3.8 b | 61.3 | 7 | 11.4 ± 3.9 c | 35.0 ± 15.8 c | LC–MS | 12333 | ||
| Nery et al. (2018) | 16 | 37.5 ± 5.9 | 31.1 ± 6.1 | 0 | 50 | ELISA | 33331 | A | |||
| O'Brien et al. (2013) | 135 | 30.3 ± 12.8 | 35 | 14.5 ± 19.1 | ELISA | 23131 | D | ||||
| Olstad et al. (2016)—women | 70 | 43.4 ± 7.2 | 26.2 ± 6.0 | 0 | 18.6 | 123.7 ± 71.2 | ELISA | 23321 | A | A | |
| Ouellette et al. (2015)—high stress mothers | 30 | 38.2 ± 3.2 | 25.3 ± 6.0 | 0 | 244.6 ± 449.5 | ELISA | 23321 | A | |||
| Ouellette et al. (2015)—low stress mothers | 30 | 37.5 ± 5.2 | 29.9 ± 8.3 | 0 | 126.7 ± 165.4 | ELISA | 23321 | A | |||
| Pickett et al. (2020) | 91 | 24.6 ± 6.5 | 30.1 ± 7.7 | 0 | 42 | 68.0 ± 161.9 | ELISA | 13131 | AC | AC | |
| Pittner et al. (2020)—adults | 171 | 44.5 ± 14.8 | 25.8 ± 4.9 | 25.1 | 19.3 | 3.5 ± 5.7 | 8.6 ± 6.9 | LC–MS | 21321 | AE | AE |
| Pulopulos et al. (2014) | 54 | 64.8 ± 4.2 | 26.3 ± 3.5 b | 24.6 | 11.1 | 2.4 ± 2.2 b | LC–MS | 21111 | A | A | |
| Qi et al. (2014) | 39 | 30.2 ± 6.1 c | 21.5 ± 2.4 | 0 | 24.9 ± 20.0 c | LC–MS | 31311 | A | |||
| Radin et al. (2019) | 166 | 42.4 ± 5.1 | 25.5 ± 5.2 | 0 | 17.1 | 52.9 ± 24.3 b | ELISA | 23121 | ACD | ACD | |
| Saleem et al. (2013)—completers | 56 | 66 ± 11 | 27.3 ± 4.2 | 85.7 | 233.2 ± 173.0 | ELISA | 33111 | A | |||
| Saleem et al. (2013)—noncompleters | 43 | 61 ± 11 | 28.5 ± 5.0 | 70 | 153.5 ± 110.5 | ELISA | 33111 | A | |||
| Schalinski et al. (2015)—healthy controls | 12 | 31.9 ± 7.5 | 22.5 ± 4.1 | 0 | 9.1 | 12.6 ± 11.0 | CLIA | 12321 | A | A | |
| Schalinski et al. (2019)—healthy controls | 75 | 25.4 ± 6.7 | 23.4 ± 3.6 | 54.7 | 5.3 | 7.3 ± 5.4 b | CLIA | 22111 | A | A | |
| Serwinski et al. (2016) | 164 | 43.6 ± 9.8 | 24.1 ± 4.4 | 0 | 10.8 | 8.4 ± 6.3 | LC–MS | 21111 | A | A | |
| Skoluda et al. (2012)—controls | 70 | 36.6 ± 11.5 | 23.0 ± 2.5 | 17.1 | CLIA | 22321 | A | ||||
| Skoluda et al. (2012)—endurance athletes | 304 | 38.3 ± 11.6 | 22.7 ± 2.3 | 41.1 | CLIA | 22321 | A | ||||
| Smith, L. et al. (2019) | 3,741 | 68.4 ± 8.0 | 28.3 ± 5.3 | 33.6 | 26.2 ± 68.8 | LC–MS | 21131 | A | |||
| Stalder et al. (2010)—nonalcoholic controls | 20 | 43.7 ± 11.2 | 26.5 ± 3.6 | 80 | CLIA | 32331 | A | ||||
| Stalder et al. (2013) | 1,258 | 39.6 ± 7.3 c | 27.1 ± 3.5 c | 84.8 | 22.5 ± 11.7 c | 38.5 ± 16.3 c | LC–MS | 21111 | ACDEFG | ||
| Stalder et al. (2014)—caregivers | 20 | 71.2 ± 6.1 | 26.7 ± 3.8 | 5 | CLIA | 22311 | A | ||||
| Stalder et al. (2014)—controls | 20 | 72.2 ± 6.4 | 25.1 ± 3.9 | 15 | CLIA | 12311 | A | ||||
| Stalder, Steudte et al. (2012)—study I | 155 | 24.1 ± 4.2 | 22.2 ± 3.4 | 26.5 | 3.9 | 17.7 ± 10.6 | CLIA | 22311 | A | ||
| Stalder, Steudte et al. (2012)—study II | 58 | 30.5 ± 12.1 | 24.0 ± 4.9 | 32.8 | 12.1 | 21.6 ± 16.0 | CLIA | 22311 | A | ||
| Staufenbiel et al. (2015) | 1,425 | 45.9 ± 13.8 | 28.2 | 3.6 ± 2.5 c | 11.1 ± 5.8 c | LC–MS | 11111 | ACEF | ACEG | ||
| Steudte et al. (2013)—nontraumatized controls | 28 | 37.6 ± 14.1 | 23.4 ± 3.05 | 10.7 | LC–MS | 11311 | A | ||||
| Steudte et al. (2013)—traumatized controls | 25 | 41.7 ± 12.3 | 23.8 ± 3.9 | 8 | LC–MS | 21311 | A | ||||
| Steudte, Kolassa et al. (2011) | 17 | 20.1 ± 5.7 | 21.4 ± 2.3 | 64.7 | CLIA | 22331 | A | ||||
| Steudte, Stalder et al. (2011) | 15 | 35.7 ± 9.3 | 22.9 ± 3.5 | 13.3 | CLIA | 12311 | A | ||||
| Steudte‐Schmiedgen et al. (2015)—nontraumatized soldiers | 129 | 26.2 ± 5.2 | 24.6 ± 2.7 | 100 | LC–MS | 21311 | A | ||||
| Steudte‐Schmiedgen et al. (2017) | 17 | 31.3 ± 9.4 b | 25.4 ± 5.0 | 11.8 | 14.1 ± 16.3 | 19.9 ± 11.3 | LC–MS | 21321 | AE | ||
| Suijker et al. (2018) | 15 | 45.2 ± 15.4 | 24.9 ± 4.7 | 43.8 | 12.5 | 21.7 ± 14.9 | ELISA | 31321 | A | A | |
| Van Aken et al. (2018) | 61 | 34.8 ± 6.7 b | 25.3 ± 4.6 b | 0 | 44.4 ± 36.2 b | ELISA | 23321 | A | |||
| Van den Heuvel, Stalder et al. (2020) | 216 | 43.8 ± 13.3 b | 31.6 ± 8.1 b | 0 | 53.7 | 6.3 ± 5.2 b , c | LC–MS | 21111 | ACD | ACD | |
| Van den Heuvel, Acker et al. (2020) | 164 | 46.5 ± 15.0 | 30.5 ± 7.3 c | 0 | 50.9 | 6.2 ± 6.4 | LC–MS | 11111 | ACD | ACD | |
| Van den Heuvel, Du Plessis et al. (2020) | 56 | 59.6 ± 8.7 | 29.5 ± 5.9 | 0 | 46.4 | 5.0 ± 4.5 b | 8.5 ± 6.2 | LC–MS | 31111 | ACDEFG | ACDEG |
| Van der Valk et al. (2020) | 51 | 40.7 ± 12.6 | 39.7 ± 5.6 | 27.5 | 100 | 5.8 ± 5.3 | 17.8 ± 13.8 | LC–MS | 31121 | ACEF | ACEG |
| Van Holland et al. (2012) | 27 | 46.2 ± 10.6 | 26 ± 4 | 81 | ELISA | 23331 | A | ||||
| Van Manen et al. (2019) | 32 | 47.8 ± 8.5 c | 27.8 ± 4.6 | 43.8 | 28.1 | 10.9 ± 11.7 | 23.9 ± 15.9 | LC–MS | 31121 | ACEF | ACEG |
| Walther et al. (2016) | 271 | 57.1 ± 10.7 | 25.4 ± 3.4 | 100 | 8.0 ± 6.3 | 24.6 ± 16.4 | LC–MS | 11333 | ADEG | ||
| Walton et al. (2013) | 10 | 28 ± 13 | 27.1 ± 3.6 | 30 | ELISA | 33311 | A | ||||
| Wang et al. (2019) | 68 | 32.5 ± 6.1 | 0 | 15 | 6.3 ± 6.5 c | LC–MS | 21323 | A | |||
| Wells et al. (2014) | 324 | 41.9 ± 15.8 | 27.0 ± 6.5 | 28.1 | 24.7 | 274.4 ± 222.0 | ELISA | 23311 | A | A | |
| Wester et al. (2014) | 47 | 45 ± 11.3 c | 23.4 | 100 | ELISA | 33123 | AC | ||||
| Wester et al. (2017) | 295 | 46.8 ± 11.7 c | 25.9 ± 4.3 | 25.4 | 19.32 | LC–MS | 11131 | AC | ACEG | ||
| Wester et al. (2017)—healthy controls | 174 | 36.3 ± 8.4 c | 26.8 ± 4.9 | 42.5 | ELISA | 23331 | A | ||||
| Wu et al. (2019) | 160 | 45.7 ± 9.8 | 26.6 ± 3.1 | 55.4 | 31 | 23.4 ± 30.5 | ELISA | 33121 | A | A | |
| Younge et al. (2015) | 151 | 41.3 ± 14.2 | 25.5 ± 4.9 | 37.1 | ELISA | 33111 | A | A | |||
| Zai et al. (2017) | 248 | 13333 | A | ||||||||
| Zekas et al. (2019) | 81 | 36.5 ± 6.2 | 100 | LC–MS | 21131 | C | |||||
| Pediatric cohorts | |||||||||||
| Bryson et al. (2020) | 297 | 3.1 ± 0.1 | 16.8 ± 1.8 | 39.4 | 22.9 | 8.5 ± 7.8 | ELISA | 23131 | A | A | |
| Chen et al. (2015)—female adolescents | 47 | 15.8 ± 3.1 | 24.3 ± 5.2 | 0 | 3.4 ± 1.9 | LC–MS | 21121 | AD | |||
| Chen et al. (2015)—male adolescents | 32 | 15.0 ± 2.1 | 21.7 ± 4.5 | 100 | 4.0 ± 2.5 | LC–MS | 21121 | AD | |||
| Condon et al. (2019) | 45 | 6.8 ± 2.1 | 0.7 ± 1.2 | 22.2 | 57.3 ± 112.7 | ELISA | 23131 | B | B | ||
| De Kruijff et al. (2020) | 278 | 10.8 ± 4.6 | −0.1 ± 1.0 | 51.1 | 0.8 | 3.1 ± 3.1 | LC–MS | 21311 | AB | AB | |
| Distel et al. (2019) | 52 | 8.4 ± 1.3 | 20.8 ± 4.4 | 39 | 29.3 | 20.6 ± 63.4 | ELISA | 23121 | A | A | |
| Evans et al. (2019) | 92 | 10.1 ± 0.3 | 17.3 ± 2.1 | 34.8 | 3.0 ± 4.5 | 10.1 ± 12.0 | LC–MS | 11121 | AE | A | |
| Föcker et al. (2016) | 20 | 17.3 ± 1.0 | −0.3 ± 1.1 | 0 | 12.6 ± 9.7 | CLIA | 12121 | B | |||
| Frisch et al. (2020) | 18 | 7.4 ± 1.0 | 15.8 ± 2.4 | 44 | 0 | 2.8 ± 2.4 | ELISA | 33321 | A | ||
| Gao et al. (2014)—young male control | 29 | 16.7 ± 0.6 | 21.4 ± 2.4 | 100 | 0 | 13.9 ± 10.9 | LC–MS | 22321 | A | ||
| Gao et al. (2014)—young male earthquake survivor | 20 | 16.8 ± 0.8 | 21.7 ± 2.4 | 100 | 0 | 25.3 ± 17.1 | LC–MS | 22321 | A | ||
| Genitsaridi et al. (2019) | 300 | 10.5 ± 2.6 | 25.7 ± 5.4 b | 25.3 | 46.7 | 8.9 ± 1.0 b | CLIA | 32131 | ACD | ||
| Gerber et al. (2017) | 318 | 7.3 ± 3.5 | 16.3 ± 2.2 | 46.9 | 8 | 12.2 ± 9.7 | CLIA | 12111 | AC | AC | |
| Golub et al. (2019) | 137 | 7.6 ± 0.6 | 16.1 ± 1.8 | 47.5 | 0 | ELISA | 13113 | A | |||
| Grunau et al. (2013)—full term | 42 | 7.8 ± 0.8 | 16.8 ± 3.2 | 35.7 | 416.2 ± 873.0 | ELISA | 33311 | A | |||
| Grunau et al. (2013)—pre‐term | 91 | 7.7 ± 0.3 | 15.7 ± 2.4 | 46.2 | 301.2 ± 560.8 | ELISA | 33311 | A | |||
| Hu et al. (2017) | 1,263 | 8.0 ± 0.8 | 47.3 | 11.8 ± 1.9 b | ELISA | 13123 | A | ||||
| Ilg et al. (2020) | 134 | 12.0 ± 4.0 | 18.6 ± 3.7 | 57 | 3.7 ± 2.3 | 13.4 ± 7.2 | LC–MS | 31323 | AE | ||
| Ince‐Askan et al. (2019) | 117 | 9.8 ± 2.4 b | 0.4 ± 1.1 b | 59.8 | 7.7 | 1.3 ± 1.0 b | 7.4 ± 3.5 b | LC–MS | 21131 | AE | ABCDEFG |
| Kamps et al. (2014) | 10 | 10.5 ± 1.3 | 0.1 ± 1.0 | 50 | 10 | 4.8 ± 4.0 | LC–MS | 11121 | AB | AB | |
| Larsen et al. (2016)—children | 363 | 5.4 ± 1.07 | 16.1 ± 1.2 | 55 | 146.5 ± 179.0 | ELISA | 23131 | A | BCD | ||
| Lehto et al. (2018) | 599 | 4.7 ± 0.9 | 15.9 ± 1.4 | 52 | 2.1 | 41 ± 77 | CLIA | 12131 | C | C | |
| Ling et al. (2020)—children | 35 | 4.7 ± 0.8 | 0.7 ± 1.0 | 51.4 | 20 | 32.0 ± 45.4 | ELISA | 23111 | B | AB | |
| Michels et al. (2017) | 81 | 12.7 ± 1.7 | −0.03 ± 0.9 | 53.6 | 0 | 25 ± 5 | LC–MS | 11121 | A | AB | |
| Murray et al. (2016) | 54 | 9.5 ± 0.3 | 17.6 ± 2.3 | 20.3 | 0 | 3.2 ± 2.9 b | ELISA | 33131 | A | A | |
| Olstad et al. (2016)—children | 30 | 14.3 ± 3.9 | 0.3 ± 1.1 | 56.7 | 10 | 96.6 ± 49.6 | ELISA | 23121 | B | B | |
| Ouellet‐Morin et al. (2016) | 34 | 17 | 26.5 | 33.0 ± 24.5 | ELISA | 13331 | A | A | |||
| Ouellette et al. (2015)—high stress daughters | 30 | 7.5 ± 0.7 | 15.3 ± 2.2 | 0 | 89.9 ± 235.1 | ELISA | 23321 | A | |||
| Ouellette et al. (2015)—low stress daughters | 30 | 7.7 ± 0.7 | 15.6 ± 2.8 | 0 | 104.4 ± 218.3 | ELISA | 23321 | A | |||
| Panter‐Brick et al. (2019) | 203 | 14.4 ± 1.7 | 0.0 ± 1.0 | 56.9 | 5.3 | 9.5 ± 10.0 | ELISA | 23121 | A | A | |
| Papafotiou et al. (2017)—normal weight | 25 | 7.8 ± 1.2 | −0.03 ± 0.6 | 0 | 1.2 ± 0.6 | LC–MS | 11121 | AB | A | ||
| Papafotiou et al. (2017)—obesity | 25 | 7.4 ± 1.3 | 2.9 ± 1.4 | 0 | 100 | 4.1 ± 5.0 | LC–MS | 31121 | A | AB | |
| Petimar et al. (2020)—mid‐childhood | 599 | 7.9 ± 0.8 | 0.3 ± 1.0 | 45.9 | 8.8 | 1.3 ± 1.5 c | LC–MS | 11121 | AC | ABC | |
| Pittner et al. (2020)—children | 61 | 12.4 ± 3.2 | 0.2 ± 1.0 | 42.6 | 3.3 | 1.6 ± 1.5 | 5.7 ± 2.9 | LC–MS | 21321 | BE | BE |
| Pyle Hennessey et al. (2020) | 100 | 5.8 ± 0.3 | 15.6 ± 1.7 | 48 | 3.1 | 6.8 ± 6.9 | ELISA | 23121 | A | A | |
| Schloss et al. (2018) | 75 | 4.6 ± 0.3 | 41.3 | ELISA | 23312 | A | |||||
| Slopen et al. (2018) | 344 | 2.1 ± 0.1 | 17.5 ± 1.7 | 43.2 | 11.1 | 19.0 ± 42.4 | ELISA | 13121 | A | A | |
| Smith, J. et al. (2019) | 114 | 8.5 ± 0.3 | 17.0 ± 2.6 | 42.1 | 4.2 ± 4.1 | ELISA | 23311 | AC | |||
| Sun et al. (2018) | 1,000 | 9.0 ± 0.9 | 18.6 ± 3.2 | 42.1 | 12.0 ± 2.0 c | ELISA | 13131 | A | A | ||
| Van Dammen et al. (2020) | 181 | 15.7 ± 2.0 | 20.3 ± 3.2 | 38.9 | 1.6 | 3.5 ± 2.1 | LC–MS | 12331 | AB | AB | |
| Vehmeijer et al. (2020) | 2042 | 6.1 ± 0.6 | 0.2 ± 0.9 | 47.5 | 3.6 | 1.9 ± 1.4 | 9.6 ± 7.4 | LC–MS | 11121 | AE | A |
| Vepsäläinen et al. (2021) | 565 | 4.8 ± 0.9 | 15.9 ± 1.5 | 37.9 | 2.1 | 40.9 ± 77.1 | CLIA | 12131 | A | A | |
| Wagner et al. (2019) | 434 | 12.0 | 38.5 | 9.9 | LC–MS | 11112 | B | ||||
| White et al. (2017) | 537 | 10.0 ± 3.1 b | 0.0 ± 0.8 | 49.3 | CLIA | 22322 | B | ||||
Note: Reported bivariate correlation/regression coefficient: A, HairF versus BMI; B, HairF versus BMI SDS; C, HairF versus WC; D, HairF versus WHR; E, HairE versus BMI; F, HairE versus WC; G, HairE versus WHR. Significant associations are represented in bold.
Abbreviations: CI, confidence interval; HairF, hair cortisol; HairE, hair cortisone; SDS, standard deviation score; WC, waist circumference; WHR, waist‐to‐hip ratio; LC–MS, liquid chromatography‐(tandem) mass spectrometry; ELISA, enzyme‐linked immunosorbent assay; CLIA, chemiluminescent immunoassay.
a
Risk of bias: 1, low risk of bias; 2, moderate risk of bias; 3, high risk of bias. Each number represents the assessed QUIPS domains. The following definitions were used for low, moderate of high risk of bias: QUIPS 1 (study participation), 1: population‐based sampling, 2: population selection on nonmedical or social conditions, 3: population selection on medical conditions not evidently related to disturbances of the HPA‐axis; QUIPS 2 (study attrition), not applicable and therefore not scored; QUIPS 3 (prognostic factor measurement), 1: HairGC analysis using LC–MS, 2: HairGC analysis using CLIA, 3: HairGC analysis using ELISA; QUIPS 4 (outcome measurement), 1: anthropometric measurements objectively measured, 2: anthropometric measurements self‐reported; QUIPS 5 (study confounding), 1: both outliers and corticosteroid use taken into account, 2: only outliers or only corticosteroid use taken into account, 3: outliers and corticosteroid use both not taken into account; QUIPS 6 (statistical analysis and reporting), 1: relevant statistics fully reported, 2: relevant statistics partly reported, 3: relevant statistics not reported.
b
Pooled subgroup means.
c
Means calculated from either median and interquartile range, or from median and range.