Table 2.
Exposure variable | Prevalence—cases, n (%) | Prevalence—controls, n (%) | Unadjusted OR (95% CI) | Adjusted OR* (95% CI) |
---|---|---|---|---|
Respiratory illness | 17 (24.3) | 12 (18.8) | 1.39 (0.60 to 3.19) | 1.39 (0.56 to 3.47) |
Influenza-like illness | 10 (14.3) | 3 (4.7) | 3.39 (0.89 to 12.92) | 3.17 (0.61 to 16.47) |
Fever | 11 (15.7) | 4 (6.3) | 2.80 (0.84 to 9.28) | 2.42 (0.54 to 10.98) |
Cough | 21 (30.0) | 10 (15.6) | 2.31 (0.99 to 5.40) | 2.04 (0.76 to 5.47) |
Sore throat | 10 (14.3) | 8 (12.5) | 1.17 (0.43 to 3.17) | 1.43 (0.44 to 4.69) |
Muscle ache | 8 (11.4) | 5 (7.8) | 1.52 (0.47 to 4.92) | 2.29 (0.59 to 8.92) |
Influenza A IgA antibodies† | 25 (46.3) | 28 (54.9) | 0.71 (0.33 to 1.53) | 0.82 (0.34 to 2.00) |
*Adjustments were made for age-group, gender, month of admission and influenza vaccination status (all exposures), family history of myocardial infarction (exposures 2, 3, 4 and 5) and personal history of myocardial infarction (exposures 2, 3, 4 and 5).
†Note that n=105 (54 cases and 51 controls) for influenza antibodies where eight equivocal results were excluded, compared with n=134 (70 cases and 64 controls) for all other exposures.