Table 1. Characteristics of CVD patients diagnosed in Sweden between 1987 and 2016, their unaffected siblings and matched population controls.
| Characteristics | Sibling comparison | Population comparison | ||
|---|---|---|---|---|
| CVD patients (N = 509,467) | Unaffected full siblings (N = 910,178) | CVD patients (N = 869,056) | Matched population controls (N = 8,690,560) | |
| Median age at index date in years (IQR) | 57 (48–65) | 55 (46–63) | 60 (51–68) | 60 (51–68) |
| Median follow-up time in years (IQR) | 8.1 (3.7–13.7) | 8.1 (3.8–13.7) | 7.7 (3.3–13.2) | 7.1 (3.2–12.4) |
| Male sex | 308,203 (60.5) | 440,177 (48.4) | 514,388 (59.2) | 5,143,880 (59.2) |
| Educational level | ||||
| <9 years | 149,555 (29.4) | 261,752 (28.8) | 272,960 (31.4) | 2,294,482 (26.4) |
| 9–12 years | 225,548 (44.3) | 413,702 (45.5) | 376,917 (43.4) | 3,548,338 (40.8) |
| >12 years | 134,364 (26.4) | 234,724 (25.8) | 219,179 (25.2) | 2,847,740 (32.8) |
| Yearly individualized family income level | ||||
| Top 20% | 107,990 (21.2) | 175,658 (19.3) | 139,098 (16.0) | 1,757,726 (20.2) |
| Middle | 301,706 (59.2) | 549,842 (60.4) | 535,109 (61.6) | 5,152,938 (59.3) |
| Lowest 20% | 99,485 (19.5) | 184,588 (20.3) | 192,858 (22.2) | 1,706,931 (19.6) |
| Unknown | 286 (0.1) | 90 (0.0) | 1991 (0.2) | 72,965 (0.8) |
| Cohabitation status | ||||
| Non-cohabitating | 223,134 (43.8) | 392,256 (43.1) | 373,337 (43.0) | 3,744,116 (43.1) |
| Cohabitating | 286,047 (56.2) | 517,832 (56.9) | 493,728 (56.8) | 4,873,479 (56.1) |
| Missing | 286 (0.1) | 90 (0.0) | 1991 (0.2) | 72,965 (0.8) |
| History of somatic disease* | 71,273 (14.0) | 79,679 (8.8) | 135,473 (15.6) | 955,030 (11.0) |
| Family history of psychiatric disorder† | 133,094 (26.1) | 251,237 (27.6) | 209,957 (24.2) | 2,003,161 (23.1) |
| Type of first-onset CVD | ||||
| Ischemic heart disease | 122,084 (24.0) | – | 212,737 (24.5) | – |
| Cerebrovascular disease | 71,030 (13.9) | – | 126,860 (14.6) | – |
| Emboli and thrombosis | 25,338 (5.0) | – | 42,857 (4.9) | – |
| Hypertensive disease | 89,818 (17.6) | – | 150,337 (17.3) | – |
| Heart failure | 15,726 (3.1) | – | 30,469 (3.5) | – |
| Arrhythmia/conduction disorder | 126,738 (24.9) | – | 210,654 (24.2) | – |
| Others | 58,733 (11.5) | – | 95,142 (11.0) | – |
| Number of cardiovascular diagnoses during follow-up | ||||
| One | 365,266 (71.7) | – | 605,615 (69.7) | – |
| Two | 99,921 (19.6) | – | 179,472 (20.7) | – |
| Three or more | 44,280 (8.7) | – | 83,969 (9.7) | – |
*
History of somatic diseases included chronic pulmonary disease, connective tissue disease, diabetes, renal diseases, liver diseases, ulcer diseases, and HIV infection/AIDS that diagnosed before index date.
†
The difference between exposed patients and unaffected full siblings was due to different number of siblings for exposed patients. The family history of psychiatric disorder was constant within each family.
IQR: interquartile range. CVD: cardiovascular disease.