BackgroundHealth checks have been suggested as an early detection approach aiming at lowering the risk of chronic disease development. This study aimed to evaluate the effectiveness of a health check programme offered to the general population, aged 30–49 years.MethodsThe entire population aged 30–49 years (N=26 216) living in the municipality of Randers, Denmark, was invited to a health check during 5 years. A pragmatic household cluster-randomised controlled trial was conducted in 10 505 citizens. The intervention group (IG, N=5250) included citizens randomised to the second year and reinvited in the 5th year. The comparison group (CG, N=5255) included citizens randomised to the 5th year. Outcomes were modelled cardiovascular disease (CVD) risk; self-reported physical activity (PA) and objectively measured cardio respiratory fitness (CRF); self-rated health (short-form 12 (SF-12)), self-rated mental health (SF-12_Mental Component Score (MCS)) and, registry information on sick-leave and employment. Due to low participation, we compared groups matched on propensity scores for participation when reinvited.ResultsParticipation in the first health check was 51% (N=2698) in the IG and 40% (N=2120) in the CG. In the IG 26% (N=1340) participated in both the first and second health checks. No intervention effects were found comparing IG and CG. Mean differences were (95% CI): modelled CVD risk: −0.052 (95% CI −0.107 to 0.003)%, PA: −0.156 (−0.331 to 0.019) days/week with 30 min moderate PA, CRF: 0.133 (−0.560 to 0.826) mL O₂/min/kg, SF-12: −0.003 (−0.032 to 0.026), SF-12_MCS: 0.355 (-0.423 to 1.132), sick leave periods ≥3 weeks: −0.004 (−0.025 to 0.017), employment: −0.004 (−0.032 to 0.024).ConclusionsPreventive health checks offered to the general population, aged 30–49 years, had no effects on a wide range of indicators of chronic disease risk.Trial registration numberNCT02028195.