Description of cases and matched controls
| . | Cases (n = 198) . | Controls (n = 878) . | Crude ORs (95% CI) . | |
|---|---|---|---|---|
| Matching factor* | ||||
| Age, y | ||||
| Mean (SD) | 49.0 (18.2) | 49.0 (18.2) | NA | |
| Median | 50.8 | 51.2 | ||
| Sex, n (%) | ||||
| Female | 119 (60.1) | 519 (59.1) | NA | |
| Male | 79 (39.9) | 359 (40.9) | ||
| Region of residence, n (%) | ||||
| Northern France | 90 (45.5) | 397 (45.2) | NA | |
| Southern France | 108 (54.5) | 481 (54.8) | ||
| Season of index date, n (%) | ||||
| Spring/summer | 119 (60.1) | 537 (61.1) | NA | |
| Fall/winter | 79 (39.9) | 341 (38.8) | ||
| Potential risk factors for ITP, n (%) | ||||
| Family history of autoimmune disorders† | ||||
| Yes | 16 (8.1) | 66 (7.5) | 1.0 (0.6-1.8) | |
| Unknown or missing | 44 (22.2) | 229 (26.1) | 0.6 (0.3-1.1) | |
| No | 138 (69.7) | 583 (66.4) | 1 | |
| Systemic NSAID(s) intake in the 12 mo before the index date | ||||
| Yes | 113 (57.1) | 498 (56.7) | 1.0 (0.7-1.4) | |
| No | 85 (42.9) | 380 (43.3) | 1 | |
| . | Cases (n = 198) . | Controls (n = 878) . | Crude ORs (95% CI) . | |
|---|---|---|---|---|
| Matching factor* | ||||
| Age, y | ||||
| Mean (SD) | 49.0 (18.2) | 49.0 (18.2) | NA | |
| Median | 50.8 | 51.2 | ||
| Sex, n (%) | ||||
| Female | 119 (60.1) | 519 (59.1) | NA | |
| Male | 79 (39.9) | 359 (40.9) | ||
| Region of residence, n (%) | ||||
| Northern France | 90 (45.5) | 397 (45.2) | NA | |
| Southern France | 108 (54.5) | 481 (54.8) | ||
| Season of index date, n (%) | ||||
| Spring/summer | 119 (60.1) | 537 (61.1) | NA | |
| Fall/winter | 79 (39.9) | 341 (38.8) | ||
| Potential risk factors for ITP, n (%) | ||||
| Family history of autoimmune disorders† | ||||
| Yes | 16 (8.1) | 66 (7.5) | 1.0 (0.6-1.8) | |
| Unknown or missing | 44 (22.2) | 229 (26.1) | 0.6 (0.3-1.1) | |
| No | 138 (69.7) | 583 (66.4) | 1 | |
| Systemic NSAID(s) intake in the 12 mo before the index date | ||||
| Yes | 113 (57.1) | 498 (56.7) | 1.0 (0.7-1.4) | |
| No | 85 (42.9) | 380 (43.3) | 1 | |
NA indicates not applicable.
Cases and controls were also matched by index date (± 2 mo).
Family history of autoimmune disorders included the following in first-degree relatives: multiple sclerosis, lupus, rheumatoid arthritis, Crohn disease, ulcerative colitis, and autoimmune thyroiditis. These data were only available for patients interviewed after September 11, 2008.