Background/Aims: We examined the potential impact of vascular risk factors including copeptin – a robust surrogate marker of arginine vasopressin associated with the metabolic syndrome and diabetes risk – on future cognitive abilities in a population-based cohort. Methods: Participants (n = 933) were investigated using baseline data, including copeptin levels, and data collected 16 years later using the Mini-Mental State Examination (MMSE) and A Quick Test of Cognitive Speed (AQT). Results: Logistic regression showed that diabetes (OR, 1.86; p < 0.05) and higher copeptin levels (OR, 1.19; p < 0.05) were independently associated with an increased risk of low AQT performance. Conclusion: Prevalence of diabetes mellitus and elevated copeptin levels in middle age predict lower cognitive speed after long-term follow-up.