Sex-specific trends in incident stroke: The Framingham Heart Study

Sex specific differences in stroke are recognized. Whether differences in incident stroke risk persists in recent periods needs further elucidation to aid public health preventive efforts. Aim: To determine long-term sex specific trends in stroke and stroke risk factors at different epochs among Framingham Heart Study participants. Methods: We examined age-adjusted 10-year stroke incidence using Cox regression in women and men in five epochs: 1962-1969 (epoch 1, reference), 1971-1976 (epoch 2), 1987-1991 (epoch 3), 1998-2005 (epoch 4), 2015-2021 (epoch 5). We compared stroke incidence by sex across epochs, estimated decade-wise linear trends overall and by sex. We compared risk factors in successive epochs to the first, and estimated sex-specific trends in risk factors. Interactions between baseline risk factors with epoch and trends were assessed by sex. Secondary analyses were repeated in participants <60 years old. Results: Incident stroke occurred in 4.5% (178/3996) in epoch 1, 3.9% (227/5786) in epoch 2, 3.9% (199/5137) in epoch 3, 2.7% (207/7642) in epoch 4, 2.2% (119/5534) in epoch 5. Men had higher risk of incident stroke in each epoch with significant difference in epochs 2 (HR 1.41, 95% CI [1.08, 1.84]) and 4 (HR 1.46, 95% CI [1.11, 1.91]) overall, and in epoch 4 (HR 2.13, 95% CI [1.17, 3.87]) among those <60 years. Stroke incidence declined by 16% per decade in men (HR 0.84, 95% CI [0.79, 0.89]) and 19% per decade in women (HR 0.81, 95% CI [0.76, 0.86]). Among those <60 years, stroke incidence declined by 22% per decade in women (HR 0.78, 95% CI [0.67, 0.95]). Hypertension declined by 8% per decade in women only ([OR] 0.92, 95% CI [0.90, 0.94]), while Atrial fibrillation and diabetes increased in both. Conclusion: Stroke incidence continues to decline in recent periods for women and men. Among participants <60 years, decline was observed only in women, possibly related to decline in hypertension in women.