AIMS: To examine the association of a reported tendency toward repetitive thinking (RT) in midlife when confronting difficulties in family and work settings with dementia many years later. METHODS: A tendency toward RT was assessed in approximately 9,000 male participants in the Israeli Ischemic Heart Disease study in 1965. The subjects were categorized according to their tendency toward RT in familial and work settings as: 1 = always forget; 2 = tend to forget; 3 = tend to think repetitively, and 4 = usually think repetitively. Dementia was assessed over 3 decades later in 1,889 participants among 2,604 survivors of the original cohort. RESULTS: The prevalence rates of dementia were 24, 19, 15 and 14% in the 4 groups of tendency toward RT in stressful work situations with superiors (p for trend < 0.0002), respectively. The prevalence rates of dementia were 21, 18, 14 and 14% in the 4 groups of tendency toward RT in familial situations (p for trend < 0.004), respectively. These associations held after multivariate analysis. CONCLUSIONS: The tendency toward RT when confronting distress is associated with a lower risk for dementia. Future studies should assess possible mechanisms and potentials for intervention and modification.