Volume 19, Number 2—February 2013
Dispatch
Risk Factors for Influenza A(H1N1)pdm09 among Students, Beijing, China
Yang Zheng1, Wei Duan1, Peng Yang, Yi Zhang, Xiaoli Wang, Li Zhang, Surabhi S. Liyanage, and Quanyi Wang
Table 1
Bivariate analysis of potential factors associated with influenza A(H1N1)pdm09 infection among students ≤18 years, Beijing, China*
| Variable | No. (%) case-patients, n = 304 | No. (%) controls, n = 608 | p value | OR (95%CI) |
|---|---|---|---|---|
| Vaccination against influenza A(H1N1)pdm09 | ||||
| No | 276 (90.8) | 264 (43.4) | Referent | |
| Yes | 28 (9.2) | 344 (56.6) | <0.001 | 0.08 (0.05–0.12) |
| Vaccination with pneumococcal vaccine | ||||
| No | 279 (91.8) | 542 (89.1) | Referent | |
| Yes | 25 (8.2) | 66 (10.9) | 0.193 | 0.72 (0.43–1.18) |
| Use of traditional Chinese medicine | ||||
| No | 103 (33.9) | 175 (28.8) | Referent | |
| Yes | 201 (66.1) | 433 (71.2) | 0.068 | 0.73 (0.51–1.02) |
| Eye rubbing | ||||
| No | 163 (53.6) | 395 (65.0) | Referent | |
| Yes | 141 (46.4) | 213 (35.0) | 0.001 | 1.68 (1.25–2.26) |
| Handwashing immediately after sneezing | ||||
| No | 151 (49.7) | 205 (33.7) | Referent | |
| Yes | 153 (50.3) | 403 (66.3) | <0.001 | 0.48 (0.36–0.65) |
| Use of soap during handwashing | ||||
| No | 37 (12.2) | 63 (10.4) | Referent | |
| Yes | 267 (87.8) | 545 (89.6) | 0.402 | 0.83 (0.53–1.29) |
| Handwashing after lessons in communal classrooms | ||||
| No | 176 (57.9) | 285 (46.9) | Referent | |
| Yes | 128 (42.1) | 323 (53.1) | 0.002 | 0.63 (0.48–0.84) |
| Handwashing after participation in outdoor sports activities | ||||
| No | 46 (15.1) | 69 (11.3) | Referent | |
| Yes | 258 (84.9) | 539 (88.7) | 0.088 | 0.69 (0.45–1.06) |
| Duration of handwashing, s | ||||
| <20 | 176 (57.9) | 347 (57.1) | Referent | |
| ≥20 | 128 (42.1) | 261 (42.9) | 0.800 | 0.96 (0.71–1.30) |
| Sleep time, h/day | ||||
| <7 | 99 (32.6) | 162 (26.6) | Referent | |
| ≥7 | 205 (67.4) | 446 (73.4) | 0.030 | 0.67 (0.47–0.96) |
| Sharing of tableware with classmates | ||||
| No | 263 (86.5) | 534 (87.8) | Referent | |
| Yes | 41 (13.5) | 74 (12.2) | 0.556 | 1.14 (0.74–1.75) |
| Classroom space/student, m2 | ||||
| <1.6 | 223 (73.4) | 412 (67.8) | Referent | |
| ≥1.6 | 81 (26.6) | 196 (32.2) | <0.001 | 0.17 (0.07–0.41) |
| Participation in outdoor activities after class | ||||
| No | 232 (76.3) | 411 (67.6) | Referent | |
| Yes | 72 (23.7) | 197 (32.4) | 0.003 | 0.58 (0.40–0.83) |
| Frequency of classroom ventilation | ||||
| >1×/h | 109 (35.9) | 160 (26.3) | Referent | |
| 1×/h | 195 (64.1) | 448 (73.9) | 0.002 | 0.61 (0.44–0.83) |
| Having meals in small restaurants near school | ||||
| No | 232 (76.3) | 460 (75.7) | Referent | |
| Yes | 72 (23.7) | 148 (24.3) | 0.808 | 0.96 (0.67–1.37) |
| Modes of transportation to and from school | ||||
| Closed (taxi, public transportation, school bus, car) | 188 (61.8) | 325 (53.5) | Referent | |
| Open (walking, bicycle, motorcycle) | 116 (38.2) | 283 (46.5) | 0.009 | 0.66 (0.48–0.90) |
| Participation in clustered social activities after school closure | ||||
| No | 266 (87.5) | 559 (91.9) | Referent | |
| Yes | 38 (12.5) | 49 (8.1) | 0.023 | 1.76 (1.08–2.86) |
*Bivariate conditional logistic regression was used to generate p values. OR, odds ratio.
1These authors contributed equally to this article.
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