The Danish National Cohort Study (DANCOS)

Introduction: The Danish National Cohort Study (DANCOS) is a nationally representative public health survey based on linkage of information in the repeated Danish Health Interview surveys, 1986-2005, to the national Danish registers on health and welfare. It facilitates studies of self-reported health behaviour and utilisation of healthcare services by subgroups and analysis of non-response bias. Research topics: DANCOS data are utilised in a variety of analyses presented here by a few examples that emphasise the impact of modifiable risk factors on public health, description of non-response bias, and the epidemiology of chronic pain and of osteoarthritis. Examples of DANCOS-based results are shown for each of the four topics. Smoking results in 24% of all deaths and, compared to other risk factors for public health, smoking accounts for the highest number of years of life lost. For non-response the mortality is higher among non-respondents than among respondents, but no significant bias on healthcare estimates can be seen. On average individuals with chronic pain had 12.8 contacts per year to the primary healthcare sector compared with 7.3 for individuals without. For osteoarthritis it is estimated that in 2020 there will be 22,600 incident cases. Conclusion: DANCOS is a public health survey linked with registers with many research possibilities. With this article we hope to stimulate further interest in the survey.