Table 1.

Coronary heart disease by age, systolic blood pressure, and cholesterol concentration according to treatment with aspirin. Figures are numbers of events/person years at entry with rates per 1000 person years in parentheses and relative risks corrected for other risk factors

	Aspirin	No aspirin	Relative risk	Interaction P value
Age (years):
45-49	14/3036 (4.6)	28/2930 (9.6)	0.48	0.055
50-54	26/3732 (7.0)	33/3831 (8.6)	0.77
55-59	34/3410 (10.0)	37/3489 (10.6)	0.73
60-64	36/3451 (10.4)	55/3325 (16.5)	0.61
65-69	44/2601 (16.9)	37/2538 (14.6)	1.29
Systolic blood pressure (mm Hg):
<130	35/5475 (6.4)	56/5249 (10.7)	0.55	0.0015
130-145	40/5348 (7.5)	57/5338 (10.7)	0.75
>145	79/5406 (14.6)	77/5526 (13.9)	0.94
Cholesterol concentration (mmol/l):
<5.9	48/5510 (8.7)	53/5552 (9.5)	0.96	0.85
5.9-6.7	39/5146 (7.6)	63/4892 (12.9)	0.55
>6.7	58/5315 (10.9)	70/5398 (13.0)	0.95