The meaning and implication of sun protection factor.

Reinau D Basel Pharmacoepidemiology Unit, Division of Clinical Pharmacy and Epidemiology, Department of Pharmaceutical Sciences, University of Basel, Basel, Switzerland.
Osterwalder U BASF Personal Care and Nutrition GmbH, Monheim, Germany.
Stockfleth E Department of Dermatology, Klinikum für Dermatologie, Venerologie und Allergologie, St. Josef-Hospital, Ruhr-Universität Bochum, Bochum, Germany.
Surber C Department of Dermatology, University Hospital, Basel, Switzerland.