Table 1.

Overall Characteristics of the Study Populations by Study Center

Auckland*MelbournePerthOxfordshireDijonNorthern SwedenTotal
Time period covered1981–20031996–19981989–19972002–20051994–20041985–20041981–2005
No. of patients with stroke280513167665431756426711 453
Person-years4 448 508737 396697 687304 3961 369 2978 474 48016 031 764
Age, y, mean (SD)71 (15)75 (14)74 (14)75 (12)73 (14)67 (7)70 (12)
Age groups, y
 15–65, n (%)804 (28.7%)247 (18.8%)161 (21.0%)100 (18.4%)449 (22.2%)1214 (28.5%)2975 (25.4%)
 65–74, n (%)684 (24.4%)298 (22.6%)170 (22.2%)138 (25.4%)432 (21.4%)3044 (71.4%)4768 (40.7%)
 ≥75, n (%)1317 (47.0%)771 (58.6%)435 (56.8%)305 (56.2%)1142 (56.5%)Not registered3977 (33.9%)
Women, %1499 (53.4%)731 (55.6%)377 (49.2%)282 (51.9%)1075 (53.1%)1608 (37.7%)5572 (47.5%)
Stroke pathological type
 Ischemic stroke, n (%)1195 (42.6%)921 (70.0%)301 (39.3%)469 (86.4%)1488 (84.7%)2541 (59.6%)6915 (60.4%)
 Intracerebral hemorrhage, n (%)234 (8.3%)191 (14.5%)87 (11.4%)48 (8.8%)194 (11.1%)433 (10.2%)1187 (10.4%)
 Subarachnoid hemorrhage, n (%)179 (6.4%)68 (5.2%)35 (4.6%)26 (4.8%)45 (2.6%)126 (3.0%)479 (4.2%)
 Undetermined stroke type, n (%)1197 (42.7%)136 (10.3%)343 (44.8%)29 (1.7%)1167 (27.3%)2872 (25.1%)
History of hypertension, n (%)1248 (45.5%)703 (54.4%)459 (61.4%)318 (59.1%)1223 (60.5%)2291 (59.2%)6242 (55.7%)
History of heart disease, n (%)672 (24.0%)246 (18.7%)470 (72.3%)111 (20.4%)424 (26.8%)Not reported1923 (17.2%)
Current smoker, n (%)992 (37.9%)402 (36.0%)285 (43.6%)218 (41.0%)Not reported356 (23.8%)2253 (35.1%)
Former smoker, n (%)577 (22.0)188 (16.8%)23 (3.5%)86 (16.1%)533 (35.5%)612 (40.9%)2019 (25.5%)
Mean [range], daily AP average18.02 [1–197]10.13 [0–144]15.70 [1–164]17.14 [1–204]13.78 [0–204]15.14 [0–246]15.26 [0–246]
Mean [range], max 3-h AP35.41 [3–300]20.93 [2–236]33.11 [3–400]34.04 [3–400]27.68 [0–400]30.34 [2–400]30.58 [0–400]
Mean [range], min 3-h AP7.10 [0–111]3.59 [0–94]5.89 [0–94]6.82 [0–80]5.43 [0–94]5.92 [0–111]5.99 [0–111]
  • Levels of geomagnetic activity (as measured by Ap Index). The daily AP average is the mean level of 3-hourly geomagnetic activity.

  • * Includes 3 studies performed in 1981 to 1982, 1991 to 1992, and 2002 to 2003.

  • Includes 2 studies: 1 performed in 1989 to 1990 and another in 1996 to 1997.

  • No strokes were recorded in people aged ≥75 years.