Scientifically, the ACS has been highly successful, largely due to the exceptional commitment of its participants, who visit the study every six months. We are deeply grateful for this long-standing engagement: some participants have been involved for over 40 years. Each year, new participants join while others leave, reflecting the dynamic nature of the cohort. Participation in the ACS is voluntary, and participants may withdraw at any time. The ACS aims to remain a good reflection of the MSM community in Amsterdam.