Supplement to: Sex and race differences in the risk of ischemic stroke associated with fasting blood glucose in REGARDS

Background: To investigate sex and race differences in the
association between fasting blood glucose (FBG) and risk of ischemic
stroke (IS). Methods: This prospective longitudinal cohort
study included adults age ≥45 years at
baseline in the Reasons for Geographic And Racial Differences in
Stroke Study, followed for a median of 11.4 years. The exposure
was baseline FBG (mg/dL); suspected IS events were
ascertained by phone every 6 months and were physician-adjudicated. Cox
proportional hazards were used to assess the adjusted sex/race-specific
associations between FBG (by category and as a restricted cubic spline)
and incident IS. Results: Of 20,338 participants, mean
age was 64.5(SD 9.3) years, 38.7% were Black, 55.4% were women, 16.2% were
using diabetes medications, and 954 IS events occurred. Compared to FBG
<100, FBG ≥150 was associated with 59% higher hazards of IS (95%CI
1.21-2.08) and 61% higher hazards of IS among those on diabetes
medications (95%CI 1.12-2.31). The association between FBG and IS varied
by race/sex (HR, FBG ≥ 150 vs. FBG <100: White women
2.05 (95% CI 1.23-3.42), Black women 1.71
(95%CI 1.10-2.66), Black men 1.24 (95%CI 0.75-2.06),
White men 1.46 (95%CI 0.93-2.28), pFBG*race/sex=0.004). Analyses
using FBG splines suggest that sex was the major contributor to
differences by race/sex subgroups. Conclusions: Sex differences in the
strength and shape of the association between FBG and IS are likely
driving the significant differences in the association between FBG and IS
across race/sex subgroups. These findings should be explored further and
may inform tailored stroke prevention guidelines.