Open Access

Jasmin Müller

• Objective Alexithymia is associated with various mental and physical disorders. Some rare evidence also suggested high alexithymia to affect the HPA axis based on small and selective samples. It was aimed to investigate the impact of alexithymia on basal cortisol levels in a large population-based cohort. Methods In a sample of N = 3444 individuals from the Study of Health in Pomerania (SHIP-TREND-0), the effect of alexithymia on basal serum cortisol levels was investigated in a cross-sectional design. Multiple linear regressions utilizing cortisol levels as the response variable and alexithymia as the predictor of interest were calculated, while adjusting for conven-tional confounding covariates including depression. Multiple stratified, moderation and mediation analyses were performed to validate the results. Results Alexithymia was not significantly associated with basal cortisol levels (b = 0.23, 95 percent confidence interval (CI) of [-0.24, 0.69]; sr2 = 0.00, CI: [-0.00, 0.00]). Sex- and age-stratified regression analyses as well as dichotomized models of non-alexithymic and alexithymic individuals substantiated the non-significance. Additional mediation analyses with (1) depression and (2) physical health (R2 > 1 in both cases) and moderation analysis regarding the interaction of physical health and alexithymia (b = -1.45, 95 percent confidence interval (CI) of [-6.13, 3.32]; sr2 = 0.00, CI: [-0.00, 0.00]) corroborated the results. Conclusion This study does not support previous findings as it shows no association between alexithymia and basal cortisol; however, a consideration of the circadian rhythm, stress exposure or specific sample compositions heeding the methodological design should be the subject of further research.