Aims/hypothesis: The aim of this study was to compare the magnitude of the effect of diabetes and stroke at baseline and during follow-up on risk of stroke mortality.
Materials and methods: Study cohorts included 25,155 Finnish men and 26,423 women aged 25-74 years. Data on diabetes and stroke history at baseline, their incidence during follow-up, and stroke death were obtained from national registers.
Results: During a mean follow-up of 18.9 years, 838 stroke deaths were recorded. In the baseline study, hazard ratios (HRs) for stroke mortality were 5.26 for men with prior diabetes only, 4.76 for men with prior stroke only, and 13.4 for men with both prior diabetes and stroke compared with men without diabetes and stroke at baseline and during follow-up. In women, the corresponding hazard ratios were 7.29, 5.27 and 5.52, respectively. When only diabetes and stroke status during the follow-up were considered, the hazard ratios for stroke mortality were 1.41 for men and 1.56 for women with incident diabetes only, 5.62 for men and 5.58 for women with incident stroke only, and 5.59 for men and 4.48 for women with both incident diabetes and stroke compared with men and women without diabetes and stroke at baseline and during follow-up.
Conclusions/interpretation: Diabetes and stroke, present either at baseline or during follow-up, markedly increase the risk of stroke death. Prior stroke at baseline carries a similar risk of stroke mortality as prior diabetes. There is a greater risk of stroke mortality associated with incident stroke during follow-up than with incident diabetes.