Table 1. Baseline characteristics of the study population.
| Risk factor | Men (N = 924233) | Women (N = 927953) | |
| Age at index date | Mean (sd) | 49.5 (11.3) | 50.5 (11.8) |
| Duration of follow-up after index date | Mean (sd) | 3.2 (3.0) | 3.4 (3.2) |
| ≥5 years | 221588 (24.0%) | 248012 (26.7%) | |
| ≥10 years | 37741 (4.1%) | 47159 (5.1%) | |
| Ethnicity | White | 444617 (48.1%) | 538979 (58.1%) |
| Black | 11699 (1.3%) | 14820 (1.6%) | |
| Indian | 8627 (0.9%) | 9805 (1.1%) | |
| Other | 17231 (1.9%) | 22210 (2.4%) | |
| Unknown | 442059 (47.8%) | 342139 (36.9%) | |
| Index of deprivation quintiles | 1 (most deprived) | 230269 (24.9%) | 237408 (25.6%) |
| 2 | 221536 (24.0%) | 227396 (24.5%) | |
| 3 | 180771 (19.6%) | 182010 (19.6%) | |
| 4 | 170552 (18.5%) | 167548 (18.1%) | |
| 5 (least deprived) | 121105 (13.1%) | 113591 (12.2%) | |
| Body mass index | Low (<20) | 12661 (1.4%) | 40105 (4.3%) |
| Normal (≥20 - <26) | 181156 (19.6%) | 273038 (29.4%) | |
| Overweight (≥26) | 249981 (27.0%) | 273694 (29.5%) | |
| Unknown | 480435 (52.0%) | 341116 (36.8%) | |
| Smoking status | No | 264612 (28.6%) | 388477 (41.9%) |
| Past | 120610 (13.0%) | 115259 (12.4%) | |
| Current | 193165 (20.9%) | 171328 (18.5%) | |
| Unknown | 345846 (37.4%) | 252889 (27.3%) | |
| Systolic blood pressure | Recorded | 596319 (64.5%) | 771566 (83.1%) |
| Mean (sd) | 133.1 (16.3) | 128 (18.0) | |
| Cholesterol HDL ratio | Recorded | 158927 (17.2%) | 168611 (18.2%) |
| Mean (sd) | 4.5 (1.4) | 3.8 (1.2) | |
| Number of records for medical events in the electronic health records in the year before | Mean (sd) | 10 (14.5) | 16.5 (17.6) |
| Treated hypertension | 72459 (7.8%) | 91125 (9.8%) | |
| Diabetes mellitus | 20144 (2.2%) | 15778 (1.7%) | |
| Atrial fibrillation | 7247 (0.8%) | 4351 (0.5%) | |
| Chronic renal disease | 4830 (0.5%) | 6998 (0.8%) | |
| Rheumatoid arthritis | 4280 (0.5%) | 10721 (1.2%) | |
| Left ventricular hypertrophy | 2297 (0.2%) | 1361 (0.1%) |