Table 2b.
PROSPER events, temperature, and cold spells by month.
| Events |
TEMPERATURE (°C) |
COLD SPELL 3 + DAYS |
COLD SPELL 4 + DAYS |
||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| PROSPER follow up period: from Dec 1997–June 2009 | Deaths, all causes, n (%) | CHD death + fatal stroke, n (%) | CHD death, n (%) | Fatal stroke, n (%) | Earliest of either non-fatal/fatal MI/Stroke, n(%), Glasgow participants | Earliest of non-fatal MI or CHD death, n (%), Glasgow participants | Earliest of non-fatal/fatal stroke, n (%), Glasgow participants | Daily average temperature °C during events days, mean (SD)2 | Daily average temperature °C during control days, mean (SD)2 | Cold spells of three days during events days, n (%)2 | Cold spells of three days during control days, n(%) 2 | Cold spells of four days during events days, n(%) a2 | Cold spells of four days during control days, n(%) a2 |
| January | 253(10.3) | 70(8.6) | 49(8.4) | 21(9.2) | 63(8.3) | 37(8.5) | 28(7.8) | 4.7(2.5) | 4.4(2.8) | 4(6.3) | 13(5.8) | 2(3.2) | 8(3.6) |
| February | 213(8.6) | 67(8.3) | 52(8.9) | 15(6.6) | 63(8.3) | 39(9.0) | 31(8.7) | 4.4(2.8) | 4.6(2.5) | 4(6.3) | 6(3.2) | 1(1.6) | 0(0.0) |
| March | 209(8.5) | 86(10.6) | 64(11.0) | 22(9.6) | 65(8.6) | 41(9.4) | 26(7.3) | 5.9(2.2) | 6.1(2.8) | 1(1.5) | 13(5.7) | 1(1.5) | 11(4.8) |
| April | 208(8.4) | 77(9.5) | 50(8.6) | 27(11.8) | 70(9.2) | 32(7.4) | 38(10.6) | 8.4(2.2) | 8.5(2.4) | 1(1.4) | 3(1.3) | 0(0.0) | 0(0.0) |
| May | 201(8.2) | 55(6.8) | 41(7.0) | 14(6.1) | 66(8.7) | 35(8.0) | 30(8.4) | 11.2(2.1) | 11.3(2.1) | 2(3.0) | 4(1.7) | 1(1.5) | 0(0.0) |
| June | 206(8.4) | 68(8.4) | 42(7.2) | 26(11.4) | 69(9.1) | 38(8.7) | 34(9.5) | 13.8(2.1) | 13.8(2.2) | 3(4.3) | 10(4.3) | 1(1.4) | 5(2.1) |
| July | 204(8.3) | 57(7.0) | 43(7.4) | 14(6.1) | 55(7.2) | 35(8.0) | 26(7.3) | 15.2(2.1) | 15.3(1.8) | 2(3.6) | 4(2.1) | 2(3.6) | 3(1.6) |
| August | 167(6.8) | 57(7.0) | 40(6.9) | 17(7.5) | 47(6.2) | 28(6.4) | 23(6.4) | 15.2(1.8) | 15.1(1.9) | 0(0.0) | 3(1.8) | 0(0.0) | 2(1.2) |
| September | 187(7.6) | 58(7.2) | 46(7.9) | 12(5.3) | 59(7.8) | 33(7.6) | 26(7.3) | 13.1(2.5) | 13.1(2.1) | 0(0.0) | 1(0.5) | 0(0.0) | 1(0.5) |
| October | 206(8.4) | 73(9.0) | 52(8.9) | 21(9.2) | 80(10.5) | 50(11.5) | 35(9.8) | 9.7(2.3) | 9.7(2.5) | 1(1.2) | 6(2.2) | 1(1.2) | 4(1.5) |
| November | 184(7.5) | 61(7.5) | 45(7.7) | 16(7.0) | 62(8.2) | 27(6.2) | 37(10.3) | 6.9(3.0) | 7.0(2.5) | 1(1.6) | 2(1.0) | 1(1.6) | 1(0.5) |
| December | 225(9.1) | 81(10.0) | 58(10.0) | 23(10.1) | 60(7.9) | 40(9.2) | 24(6.7) | 4.0(3.0) | 4.1(3.1) | 0(0.0) | 3(1.5) | 0(0.0) | 1(0.5) |
| Overall year | 2463(100) | 810(100) | 582(100) | 228(100) | 760(100) | 435(100) | 358(100) | 9.2(4.6) | 9.3(4.6) | 19(2.5) | 68(2.6) | 10(1.3) | 36(1.4) |
| Difference winter vs non-winter (%)1 | + 18 | + 23 | + 27 | + 13 | + 1 | + 15 | − 11 | ||||||
1
By convention, the events per day in the four coldest ‘winter’ months (December, January, February, March for the northern hemisphere), minus the events per day over other, ‘non-winter’ months, all divided by the average number of events per day over the non-winter months, multiplied by 100.
2
The ‘events’ definition used in this column refers to the earliest of fatal/non-fatal stroke or CHD death/non-fatal MI during the study period.