Table 3.
Univariate analysis of characteristics and their RR of ILI
| Characteristic | ILI | No ILI | Univariate RR (95% Cl) | Univariate P-value |
|---|---|---|---|---|
| Malaria prophylaxis | ||||
| Doxycycline | 29 (5%) | 615 (95%) | 0.46 (0.32–0.67) | < 0.01 |
| Other or none | 252 (10%) | 2,331 (90%) | Ref | |
| Other | 144 (9%) | 1,479 (91%) | 0.78 (0.62–0.99) | |
| None | 108 (11%) | 852 (89%) | Ref | |
| Gender | ||||
| Male | 121 (6%) | 1,885 (94%) | Ref | |
| Female | 160 (12%) | 1,061 (88%) | 2.16 (1.73–2.72) | < 0.01 |
| Age (years, IQR) | 54 (31,66) | 38 (27,57) | – | < 0.01 |
| Median duration of travel (days, IQR) | 21 (14,36) | 19 (12,42) | – | 0.03 |
| Destinations | ||||
| Africa | 75 (7%) | 958 (93%) | 0.77 (0.60–0.99) | 0.05 |
| Asia | 133 (10%) | 1,166 (90%) | 1.26 (1.00–1.58) | 0.04 |
| South America | 46 (14%) | 286 (86%) | 1.70 (1.27–2.29) | 0.04 |
| Mexico/Caribbean/Central America | 53 (9%) | 557 (91%) | 0.99 (0.75–1.32) | 0.99 |
| Multiple regions | 93 (9%) | 920 (91%) | 1.08 (0.85–1.37) | 0.52 |
| Purpose of travel | ||||
| Military | 53 (4%) | 1,415 (96%) | 0.28 (0.20–0.37) | < 0.01 |
| Vacation | 176 (22%) | 1,106 (78%) | 2.54 (2.02–3.20) | < 0.01 |
| Visiting friends and relative | 46 (12%) | 340 (88%) | 1.44 (1.06–1.94) | 0.02 |
| Medical | 10 (7%) | 138 (3%) | 0.76 (0.42–1.41) | 0.39 |
| Travel accommodations | ||||
| Hotel | 180 (10%) | 1,666 (90%) | 1.33 (1.06–1.68) | 0.02 |
| Cruise* | 73 (21%) | 281 (79%) | 2.84 (2.23–3.63) | < 0.01 |
| Military | 20 (10%) | 178 (90%) | 1.17 (0.76–1.80) | 0.47 |
ILI = influenza-like illness; RR = relative risk.
* Including deployment on USS comfort.