Cumulative life course impairment across cultures and medical systems.

Life course epidemiology is very important in the evaluation of chronic diseases and their long term physical, psychological, cognitive and social consequences. However, chronic dermatologic diseases can have a different impact on quality of life depending on patients' cultures and medical systems. Conversely, cultural, social and economic factors over life may lead to even greater health disparities. Moreover, individuals with same diseases and disease severities, but with diverse cultural backgrounds and medical systems, may value health differently and this has to be taken into account when performing multinational studies of cumulative life course impairment. Some processes and concepts involved in cross-cultural comparison of quality of life studies are described here, including the small number of international studies that have been performed to evaluate quality of life instruments across different cultures to date. Cross-cultural impact of dermatologic diseases on subjects' life as well as studies evaluation of different dermatology-specific quality of life instruments are discussed.