35 Years of health surveys in Denmark: a backbone of public health practice and research.

Denmark has a 35-year history of monitoring health status in the general population through health surveys. In this commentary, we outline the development of health surveys in Denmark from the beginning in 1987 to the present time. We describe how the current systematic framework for the Danish National Health Survey (DNHS) developed. We discuss the methodological basis for the DNHS and describe its application in public health practice and research. Over the years, the DNHS has become an important part of the Danish public health environment. Challenges for the DNHS in the future are to adapt to new trends in public health and at the same time to be able to monitor important changes consistently over time.