Low hair cortisol concentration and emerging attention‐deficit/hyperactivity symptoms in preschool age

Abstract

Previous research demonstrated hypoactivity of the HPA axis in children with attention-deficit/hyperactivity disorder (ADHD) or externalizing symptoms. We analyzed the predictive association between the long-term HPA axis activity and increasing symptoms of ADHD in the preschool period. The sample consisted of n = 125 4-year-old children and their families (including n = 64 children with elevated ADHD symptoms). ADHD symptoms were assessed by a structured clinical interview with the mother and by parent- and teacher-report questionnaires. The long-term HPA axis activity was assessed by the hair cortisol concentration (HCC) (over a 3-month period). After controlling for potential confounders, low HCC predicted an increase in ADHD symptoms between the age of 4 and 5 years. Exploration of gender effects revealed that cross-sectional and predictive associations were significant in boys but not in girls. Low HCC might thus be regarded as an early marker of a possibly gender-related developmental pathway to ADHD.

Body mass index, waist circumference and body fat are positively correlated with hair cortisol in children: A systematic review and meta‐analysis

“…Of the 28 studies included in this systematic review (see Table S1), 11 (39.3%) 21–31 were rated as having a high risk of bias, and 17 were rated as having a low risk of bias. For the 11 studies with a high risk of bias, the rating was due to potential confounding: Researchers failed to adjust potential confounders when examining the relationship between HCC and anthropometric factors.…”

“…For the 11 studies with a high risk of bias, the rating was due to potential confounding: Researchers failed to adjust potential confounders when examining the relationship between HCC and anthropometric factors. Two studies also had potential bias in participant selection, as participants were recruited conveniently from a previous trial 22 or selection was based on a prior defined distribution 26 . Three studies either included self‐reported height and weight data or did not clearly describe if height and weight were subjectively reported or objectively measured 22,26,32 .…”

“…Two studies also had potential bias in participant selection, as participants were recruited conveniently from a previous trial 22 or selection was based on a prior defined distribution 26 . Three studies either included self‐reported height and weight data or did not clearly describe if height and weight were subjectively reported or objectively measured 22,26,32 . Only six studies excluded children using corticosteroid drugs 23,25,30,32–34 …”

“…Table S2 displays a summary of the 28 studies included in the systematic review 21–48 . Of the 28 studies, only four were conducted in the United States, with the remaining ones conducted in Europe ( n = 16; seven in Netherlands, four in Germany, two in Greece, one in Switzerland, one in Belgium and one in Denmark), Australia ( n = 4), China ( n = 2), Canada ( n = 1) or Jordan/Lebanon/Iraq/Syria/Turkey ( n = 1).…”

“…The majority were cross‐sectional descriptive studies ( n = 23). In the five remaining studies (two longitudinal studies, 26,45 one randomized controlled trial, 31 one cohort study 33 and one case–control study 27 ), all the correlations between HCC and anthropometric factors were cross‐sectional.…”