Objective: To study the role of cerebrovascular hemodynamic indexes (CVHI) changing in stroke and to provide reference for stroke prevention and risk factor study.
Methods: From 2003 to 2004, participants aged 40 years and above in two communities in Fengxian district were recruited by cluster sampling. Risk factors of stroke and CVHI were investigated and checked during baseline investigation. A total of 10 565 individuals completed the survey and met the inclusion criterion. After baseline investigation, the cohort was followed up for stroke occurrence. Relative risk (RR) of CVHI and common risk factors were estimated by cohort study design.
Results: Age of the cohort was (56.2 ± 11.4) years. 4444 (42.1%) were males and 6121 (57.9%) were females. Total follow-up duration was 67 885.7 person-years. A total of 195 stroke cases occurred and incidence density of stroke was 287.2 per 100 000 person-years. Stroke incidence in exposure groups of hypertension, heart disease and alcohol drinking was 3.47% (108/3118), 2.96% (21/710) and 2.50% (47/1882), respectively. The incidence in corresponding non-exposure group was 1.17% (87/7448), 1.77% (174/9855) and 1.70% (148/8683) respectively. There was significant difference between 2 groups (χ(2) value was 62.72, 4.56 and 4.94, respectively, P < 0.05). Stroke incidence in CVHI score < 25, 25 - 49, 50 - 74 and ≥ 75 groups was 9.12% (59/647), 5.68% (44/775), 2.52% (39/1545) and 0.72% (53/7403)(χ(2)trend = 273.57, P < 0.05), respectively. Incidence of stroke in 40 - 49, 50 - 59, 60 - 69, ≥ 70 years age group was 0.22% (8/3565), 1.28% (43/3357), 2.71% (50/1848) and 5.88% (94/1600) (χ(2)trend = 181.48, P < 0.05), respectively. Multiple Cox regression analysis indicated that RR (95%CI) value of hypertension and cigarette smoking was 1.40(1.02 - 1.92) and 1.59(1.19 - 2.12), respectively when comparing with non-exposure group. RR (95%CI) value in CVHI score < 25, 25 - 49 and 50 - 74 points group were 6.15 (4.08 - 9.26), 4.55 (2.98 - 6.96) and 2.68 (1.75 - 4.09), respectively when comparing with the score ≥ 75 points group. RR (95%CI) value in age 50 - 59, 60 - 69 and ≥ 70 years group was 4.61 (2.16 - 9.82), 7.81 (3.67 - 16.60) and 13.49(6.44 - 28.24), respectively when comparing with below 40 years group.
Conclusion: CVHI score is the strong independent predictive factor and hypertension, cigarette smoking and age are the independent risk factors of stroke.