1. 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.

2. First author
M.G.H. Sanders, MD

3. 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

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

5. 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

6. Results (1) - Characteristics

7. Results (2) Logistic regression

8. Results (3) – subgroup analysis
Total testosterone in men
adjusted OR 1.00 ( )
Free androgen index in woman
adjusted OR 1.01 ( )
No association found

9. 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

10. 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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