Prevalence and determinants of seborrhoeic dermatitis in a middle aged and elderly population: the Rotterdam Study M.G.H. Sanders, MD1, L.M. Pardo, MD, PhD1, O.H. Franco, MD, PhD2, R.S. Ginger, PhD3, T Nijsten, MD, PhD1. 1. Department of Dermatology, Erasmus Medical Center, Rotterdam, The Netherlands 2. Department of Epidemiology, Erasmus Medical Center, Rotterdam, The Netherlands 3. Unilever Research and Development, Colworth Science Park, Sharnbrook, UK.

First author M.G.H. Sanders, MD

Introduction What’s already known? Seborrhoeic dermatitis is a common chronic relapsing inflammatory skin disease with unclear pathophysiological mechanism Numerous host and environmental factors have been implicated in the pathogenesis of seborrhoeic dermatitis, but  most have not been validated

Objective To establish which lifestyle and physiological determinants are associated with seborrhoeic dermatitis

Methods Study population: comparative cross-sectional study from the Rotterdam Study, an ongoing prospective population based cohort study of chronic diseases in a middle aged and elderly population in the Ommoord district of Rotterdam, The Netherlands Case definition: full body skin examination by physician Selection of potential factors: literature search of PubMed, Embase, Web-of-science and Google Scholar

Results (1) - Characteristics

Results (2) Logistic regression

Results (3) – subgroup analysis Total testosterone in men adjusted OR 1.00 (0.98-1.02) Free androgen index in woman adjusted OR 1.01 (0.92-1.10) No association found

Discussion What does this study add? Male sex, light skin colour and dry skin and winter season increase the risk of SD No association between testosterone (men) or FAI (women) and SD Improving barrier function may be a target in the treatment of seborrhoeic dermatitis

Research team M.G.H. Sanders, MD L.M. Pardo, MD, PhD O.H. Franco, MD, PhD R.S. Ginger, PhD T. Nijsten, MD, PhD1.

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