Table 1.
Characteristics of chronic lymphocytic leukemia patients and controls
| Variable | Patients | Controls |
|---|---|---|
| Total no. | 4 249 | 15 690 |
| Age, median (interquartile range), y | 71 (63-79) | 71 (63-78) |
| Age group, n (%) | ||
| Younger than 65 y | 1 286 (30) | 4 875 (31) |
| 65 y or older | 2 963 (70) | 10 815 (69) |
| Sex, n (%) | ||
| Male | 2 552 (60) | 9 448 (60) |
| Female | 1 697 (40) | 6 242 (40) |
| Calendar year, median (interquartile range) | 1988 (1983-1993) | 1988 (1983-1993) |
| Personal history of any defined airway infection, n (%)* | ||
| 1 infection | 152 (3.6) | 444 (2.8) |
| 2 infections | 40 (0.9) | 126 (0.8) |
| 3 or more infections | 34 (0.8) | 116 (0.7) |
*
Pneumonia, bronchitis, lower-airway unspecified, laryngitis, nasopharyngitis/pharyngitis, upper-airway unspecified, sinusitis, otitis media/mastoiditis, influenza, and tuberculosis.