Characteristics of cases and controls (n=34 661)
| Characteristics | Controls (n=29 697) | Cases (n=4964) | Unadjusted OR (95% CI) |
|---|---|---|---|
| Age (years) | |||
| <25 | 4598 (15.48%) | 766 (15.43%) | Matching variable |
| 25–50 | 5585 (18.81%) | 932 (18.78%) | |
| 51–75 | 10 082 (33.95%) | 1675 (33.74%) | |
| >75 | 9432 (31.7%) | 1591 (32.05%) | |
| Sex | |||
| Male | 13 760 (46.33%) | 2304 (46.41%) | Matching variable |
| Female | 15 937 (53.67%) | 2660 (53.59%) | |
| Current smokers | |||
| No | 24 591 (82.81%) | 3745 (75.44%) | 1.00 |
| Yes | 5106 (17.19%) | 1219 (24.56%) | 1.69 (1.57 to 1.83)* |
| Previous pneumonia | |||
| No | 28 935 (97.43%) | 4518 (91.02%) | 1.00 |
| Yes | 762 (2.57%) | 446 (8.98%) | 4.04 (3.56 to 4.59)* |
| Townsend score deprivation quintile | |||
| 1 (least deprived) | 6546 (22.04%) | 983 (19.80%) | 1.00 |
| 2 | 6408 (21.58%) | 973 (19.60%) | 1.02 (0.93 to 1.13) |
| 3 | 5541 (18.66%) | 947 (19.08%) | 1.18 (1.07 to 1.31) |
| 4 | 5132 (17.28%) | 904 (18.21%) | 1.24 (1.12 to 1.38) |
| 5 (most deprived) Missing | 3971 (13.37%) | 781 (15.73%) | 1.42 (1.27 to 1.60) |
| 2099 (7.07%) | 376 (7.57%) | – | |
| p trend <0.001 | |||
| Myocardial infarction | |||
| No | 26 757 (90.10%) | 4334 (87.31%) | 1.00 |
| Yes | 2940 (9.90%) | 630 (12.69%) | 1.36 (1.23 to 1.50)* |
| Charlson's comorbidity index score | |||
| 0 | 17 303 (58.27%) | 1939 (39.06%) | 1.00 |
| 1–2 | 9173 (30.89%) | 1964 (39.56%) | 2.27 (2.11 to 2.44) |
| 3–5 | 2997 (10.09%) | 929 (18.71%) | 3.74 (3.38 to 4.13) |
| >5 | 224 (0.75%) | 132 (2.66%) | 7.43 (5.91 to 9.34) |
| p trend <0.001 | |||
| Depression | |||
| No | 26 380 (88.83%) | 4123 (83.06%) | 1.00 |
| Yes | 3317 (11.17%) | 841 (16.94%) | 1.71 (1.57 to 1.87)* |
| Psychosis | |||
| No | 29 565 (99.56%) | 4930 (99.32%) | 1.00 |
| Yes | 132 (0.44%) | 34 (0.68%) | 1.54 (1.06 to 2.25) |
| Alcohol | |||
| Below limit | 18 308 (61.65%) | 3137 (63.20%) | 1.00 |
| Above limit | 11 389 (38.35%) | 1827 (36.80%) | 0.90 (0.83 to 0.98) |
| Lung diseases | |||
| No | 26 493 (89.21%) | 3763 (75.81%) | 1.00 |
| Yes | 3204 (12.44%) | 1201 (24.19%) | 2.74 (2.54 to 2.96)* |
Statistically significant (p≤0.05) results are in bold.
*p<0.001.