The multidisciplinary expertise regarding co-morbidities which is present within the AMC in close collaboration with the existing data collection structures of the HIV Monitoring Foundation (HMF) and the Cluster of Infectious Diseases of the Public Health Service Amsterdam (PHSA), offers a unique opportunity to systematically identify the burden of co-morbidity, their (known) risk factors and their effect on quality of life among HIV-infected individuals and in a comparable group of uninfected individuals.