Temporal Trends of Sex Differences in Transient Ischemic Attack Incidence Within a Population

Previously we reported that ischemic stroke incidence is declining over time for men but not women. We sought to describe temporal trends of sex differences in incidence of transient ischemic attack (TIA) within the same large, biracial population.

Among the population of 1.3 million in the Greater Cincinnati Northern Kentucky Stroke Study (GCNKSS) region, TIAs among area residents (≥20 years old) were identified at all local hospitals. Out of hospital cases were ascertained using a sampling scheme. First-ever cases and first within each study period for a patient was included in incidence rates. All cases were physician-adjudicated. Incidence rates (during July 93-June 94 and calendar years 1999, 2005, and 2010) were calculated using the age-, race-, and sex-specific number of TIAs divided by the GCNKSS population in that group; rates were standardized to the 2010 U.S.

t Tests with Bonferroni correction were used to compare rates over time.

There were a total of 4746 TIA events; 53% were female, and 12% were black. In males, incidence decreased from 153 (95% confidence interval [CI] 139-167) per 100,000 in 1993/4 to 117 (95% CI 107-128) in 2010 (P < .05 for trend test) but was similar over time among females (107 (95% CI 97-116) to 102 (95%CI 94-111), P > .05).

Within the GCNKSS population, TIA incidence decreased significantly over time in males but not females, data which parallels trends in ischemic stroke in the GCNKSS over the same time period. Future research is needed to determine if these sex differences in incidence over time continue past 2010.