The Influence of Psychological Stress on the Levels of the Skin's Natural Moisturizing Factor in Croatian Medical Students.

Psychological stress may affect skin barrier homeostasis and slow down its recovery. Therefore, we aimed to examine the association between psychological stress levels and natural moisturizing factor (NMF) levels in the stratum corneum (SC). NMF levels were determined in the SC of 25 third-year and 25 sixth-year medical students in two periods (stressful and non-stressful) using the tape stripping method, high-performance liquid chromatography, and spectrophotometry. Additionally, students completed the Perceived Stress Scale questionnaire. Most students had medium stress levels. During the non-stressful period, third-year students were under higher stress than sixth-year students (P<0.001). However, there was no significant difference between the two examined groups in the stressful period. Only among the sixth-year students were significantly higher stress levels found in the stressful period compared with the non-stressful period. In both groups, the levels of NMF did not differ significantly between the examined periods. Regarding the non-stressful period, there was a clear trend of increasing NMF levels among third-year students compared with sixth-year students (P=0.0547), consistent with the higher stress levels among third-year students during this period. Additionally, sixth-year female students had significantly lower NMF levels during the non-stressful period than third-year female students. In conclusion, third-year students were exposed to longer-term stress, while the stress of sixth-year students was associated with the exam-writing period. Additionally, we observed a trend of increasing NMF levels with increasing stress. Further research is needed to determine the mechanism by which stress, as an independent factor, influences NMF levels in the SC.