The incidence of stroke and transient ischaemic attacks is falling: a report from the Belgian sentinel stations.

Abstract

BACKGROUND: Increasing as well as decreasing trends in stroke incidence have been described. AIM: To examine time trends associated with the incidence of stroke and transient ischaemic attacks (TIAs) within an ongoing registration network. DESIGN OF STUDY: Analysis of data from a network of sentinel practices. SETTING: Sentinel practice population (approximately 1.4% of the total Belgian population. METHOD: Attack incidence rates of both stroke and TIA were studied at four one-year registration periods between 1984 and 1999. RESULTS: The number of events identified as stroke was 1097 (513 in males and 584 in females). The percentage of first-ever stroke was 69%, 64%, and 70% in 1989, 1998, and 1999 respectively. The number of events identified as TIAs was 382 (165 in males and 217 in females). The percentage of first-ever TIA was 65%, 69%, and 75% in 1989, 1998, and 1999 respectively. Yearly age-standardised attack rates of stroke significantly decreased during the registration period from 2.86 per 1000 in 1984, to 1.62 per 1000 in 1999 (chi2 for trend, P = 0.04) in males and from 2.97 per 1000 to 1.96 per 1000 (P = 0.007) for females. The decrease was restricted to subjects aged over 60 years. For TIA, a significant decrease (P = 0.014) was identified in females, but not in males (P = 0.61). Crude attack rates of stroke also significantly decreased, with an overall decrease between 1984 and 1999 of 37% in males and 26% in females. No such trend was found for TIA (P = 0. 63 for males and P = 0.35 for females). CONCLUSION: Both crude and age-standardised attack rates of stroke show a clear and significant decrease between 1984 and 1999. For TIA, a weaker trend was identified.