Table 1.
Characteristics of the Study Population in the Discovery Cohorts for Analysis of Incident Total Stroke and Incident Ischemic Stroke.*
| Variable | ARIC (N = 7686) | CHS (N = 2022) | FHS (N = 4131) | Rotterdam (N = 5763) |
|---|---|---|---|---|
| Female sex (%) | 53 | 55 | 55 | 59 |
| Mean follow-up (yr) | 15 | 11 | 6 | 10 |
| Mean age (yr) | ||||
| At DNA draw | 54±6 | 73±6 | 66±12 | 69±9 |
| At incident stroke | 66±7 | 81±6 | 80±10 | 80±8 |
| Strokes (no.) | ||||
| Prevalent | 12 | 0‡ | 135 | 170 |
| Incident total | 312 | 459 | 156 | 617 |
| Incident ischemic | 277 | 389 | 131 | 367 |
| Incident atherothrombotic | 243 | 264 | 82 | 296 |
| Cardiovascular risk factors at baseline† | ||||
| Systolic blood pressure (mm Hg) | 118±17 | 138±22 | 131±20 | 139±22 |
| Diastolic blood pressure (mm Hg) | 72±10 | 71±11 | 74±10 | 74±12 |
| Hypertension (%) | 27 | 61 | 52 | 61 |
| Diabetes mellitus (%) | 6 | 14 | 12 | 10 |
| Current smoker (%) | 25 | 11 | 14 | 23 |
| Prevalent cardiovascular disease other than stroke (%) | 5 | 0‡ | 16 | 10 |
Plus–minus values are means ±SD. Sample numbers include only genotyped persons who also provided consent for these analyses and had high-quality genotyping (i.e., that met quality-control criteria). ARIC denotes Atherosclerosis Risk in Communities, CHS Cardiovascular Health Study, and FHS Framingham Heart Study.
The definition of baseline risk factors was uniform in all four studies. Hypertension was defined with the use of criteria from the seventh report of the Joint National Committee on Prevention, Detection, Evaluation, and Treatment of High Blood Pressure: systolic blood pressure of 140 mm Hg or more, diastolic blood pressure of 90 mm Hg or more, or the use of an antihypertensive agent. Diabetes mellitus was defined as a blood glucose level of 200 mg per deciliter (11 mmol per liter) or more in a random or 2-hour postprandial specimen, a fasting blood glucose level of 126 mg per deciliter (7 mmol per liter) or more, or the use of insulin or oral hypoglycemic agents. Cardiovascular disease was defined as the presence of congestive heart failure, coronary heart disease, or intermittent claudication.
In the CHS, persons with prevalent stroke or other cardiovascular disease were not genotyped.