Table 2.
Association between prior history of airway infection and risk of chronic lymphocytic leukemia
| Infection category/site | Patients | Controls | OR (95% CI) |
|---|---|---|---|
| Lower airways | |||
| Pneumonia | 127 | 330 | 1.4 (1.2-1.8) |
| Latency interval, y* | |||
| 1-4.99 | 93 | 221 | 1.6 (1.2-2.0) |
| 5 or more | 44 | 124 | 1.3 (0.9-1.8) |
| No. of infections | |||
| 1 | 100 | 267 | 1.4 (1.1-1.8) |
| 2 | 17 | 48 | 1.3 (0.8-2.9) |
| 3 or more | 10 | 15 | 2.5 (1.1-5.6) |
| Age at CLL diagnosis, y | |||
| Younger than 65 | 6 | 21 | 1.1 (0.4-2.7) |
| 65 or older | 121 | 309 | 1.5 (1.2-1.8) |
| Sex | |||
| Male | 77 | 210 | 1.3 (1.0-1.8) |
| Female | 50 | 120 | 1.5 (1.1-2.2) |
| Bronchitis | 76 | 278 | 1.0 (0.8-1.3) |
| Lower-airway infection, unspecified | 20 | 54 | 1.4 (0.8-2.3) |
| Upper-airways, sinus, and middle ear | |||
| Laryngitis | 9 | 20 | 1.7 (0.8-3.7) |
| Nasopharyngitis/pharyngitis | 3 | 10 | 1.1 (0.3-4.0) |
| Upper-airway infection, unspecified | 6 | 27 | 0.8 (0.3-2.0) |
| Sinusitis | 6 | 11 | 2.0 (0.8-2.0) |
| Otitis media/mastoiditis | 10 | 25 | 1.5 (0.7-3.1) |
| Other | |||
| Influenza | 10 | 28 | 1.3 (0.6-2.7) |
| Tuberculosis | 11 | 30 | 1.3 (0.7-2.7) |
ORs were adjusted for age, calendar time of CLL diagnosis, and sex. The table includes only events that occurred more than 1 year prior to CLL diagnosis. Applied ICD 8th and 10th revisions codes are as follows: pneumonia: ICD 8: 480, 481-482, 483.08, 483.09, 484-486; ICD 10: J12-J16, J18; bronchitis: ICD 8: 491; ICD 10: J41, J42; lower-airway unspecified: ICD 8: 466; ICD 10: J208, J209, J218, J219, J22; laryngitis: ICD 8: 506; ICD 10: J37; nasopharyngitis/pharyngitis: ICD 8: 460, 502; ICD 10: J00, J31; upper-airway unspecified: ICD 8: 461-465; ICD 10: J01, J208, J209, J308, J309, J04-J06; sinusitis: ICD 8: 503; ICD 10: J32; otitis media/mastoiditis: ICD 8: 381.19, 381.29, 383.19; ICD 10: H652, H653, H701; influenza: ICD 8: 470-474; ICD 10: J10, J11; tuberculosis: ICD 8: 011-019; ICD 10: A15-A19, B90.
Since outpatient data were only available beginning in 1994, we examined the association separately for infections diagnosed from 1977 to 1993 and 1994 to 1997; risk estimates were virtually the same. Because subjects could contribute pneumonia episodes to more than 1 latency interval, the latency totals do not sum to the total number of people with pneumonia. Risk estimates stratified by latency were virtually unchanged when the 1- to 4.99- and 5-or-more–year intervals were analyzed simultaneously in a multivariate model.
OR indicates odds ratio; CI, confidence interval; and italic entries have P values less than .05.
Time from discharge listing a defined airway infection until CLL diagnosis.