A new original article by dr. Irena Martinović Klarić and collegues from the project of the Croatian Science Foundation „Modernity Stress, Youth and Migrations“ (09.01/408) was recently published in the journal Biochemia Medica (IF for 2015. is 3.051).
Daniela Šupe-Domić, Goran Milas, Irena Drmić Hofman, Lada Rumora and Irena Martinović Klarić published the article „Daily salivary cortisol profile: Insights from the Croatian Late Adolescence Stress Study (CLASS)“.
The goal of the study was to gain knowledge about basal hypothalamic-pituitary-adrenal (HPA) axis activity in late adolescence. The total analytic sample consisted of 903 upper secondary school students aged 18 to 21 years. It was a probabilistic two-stage cluster sample stratified according to the type of school (gymnasium/vocational) from four largest cities in Croatia (Split, Rijeka, Osijek and Zagreb). Cortisol was sampled at home at three time points (at awakening, 30 to 45 minutes after awakening and at bedtime) over the course of one day. Two major determinants of the basal salivary cortisol activity were revealed: gender and awakening-bedtime rhythm. Female students had a more robust cortisol awakening response, a steeper diurnal cortisol decline and a greater area under the cortisol curve than male students. Those students who woke-up earlier and were longer awake (“early risers” and “short sleepers”) had a more robust cortisol awakening response, a flatter cortisol slope and a larger area under the cortisol curve than students who woke-up later and were shorter awake (“night birds”, “sleepy heads” and “sleeping beauties”). Minor, but significant predictors of the basal HPA axis activity revealed potentially vulnerable sub-groups in late adolescence, such as male drug abusers and females without a best friend.