Skin autofluorescence of advanced glycation end products and course of affective disorders in the lifelines cohort study, a prospective investigation

Background: Skin autofluorescence (SAF), indicating concentration of advanced glycation end products in the skin and oxidative stress, is cross-sectionally associated with affective disorders. Prospective studies of oxidative stress markers will help to clarify the pathophysiological role of oxidative stress. Methods: Data of a population-based cohort study were used. Presence of major depressive disorder, dysthymia, generalised anxiety disorder, panic disorder or social phobia was assessed at baseline and at 5-year follow-up with the Mini-International Neuropsychiatric Interview. Associations between SAF at baseline and incidence and persistence/recurrence of affective disorders were assessed with logistic regression. Results: Of 43,267 participants with no disorder at baseline, 2885 (6.7%) developed an incident disorder during follow-up. In 1360 of 3648 participants (37.3%) with an affective disorder at baseline, a persisting/recurrent disorder was present at follow-up. A modest association existed between SAF and incident affective disorders (OR=1.07 [95%CI 1.03-1.12], P<.001), specifically major depressive disorder (OR=1.11 [95%CI 1.04-1.19], P=.003); this association lost statistical significance after adjustment for sociodemographic factors. Associations between SAF and persistence/recurrence were not significant. Limitations: Many confounders might also act as intermediate: extensive adjustment for confounders caused overfitting and possibly masked effects of SAF on course of affective disorders. Relatively small sample sizes for analyses of SAF and persistence/recurrence of affective disorders resulted in a low power. Conclusions: Increased SAF modestly raises the odds of incident affective disorders, particularly major depressive disorder, providing evidence that oxidative stress plays a role in subsequent occurrence of affective disorders. However, significance of effects faded after adjustment for socioeconomic status.