Table 3. Risk factors for acute respiratory illness among cohort participants.
| Characteristic | N | Incidence rate of acute respiratory illness per person year of follow-up | Univariable analysis b | Multivariable analysis b | |||
|---|---|---|---|---|---|---|---|
| IRR (95% CI) | P value | IRR (95% CI) | P value | ||||
| HIV status | HIV positive | 136 | 2.08 (1.81–2.38) | 0.87 (0.70–1.07) | 0.18 | 0.81 (0.61–1.06) | 0.13 |
| HIV negative | 73 | 2.30 (1.94–2.70) | 1 | 1 | |||
| Gender | Female | 48 | 1.97 (1.56–2.48) | 0.84 (0.54–1.23) | 0.42 | 0.88 (0.65–1.21) | 0.45 |
| Male | 161 | 2.21 (1.95–2.47) | 1 | 1 | |||
| Age (years) | 65+ | 24 | 1.98 (1.42–2.68) | 0.94 (0.67–1.32) | 0.40 | 0.87 (0.58–1.31) | 0.90 |
| 55–65 | 35 | 2.19 (1.69–2.79) | 1.04 (0.79–1.38) | 1.03 (0.82–1.46) | |||
| 45–55 | 104 | 2.19 (1.89–2.53) | 1 | 1 | |||
| <45 | 46 | 2.11 (1.64–2.67) | 0.83 (0.63–1.09) | 0.98 (0.68–1.43) | |||
| Tobacco Smoking | Current smoker | 51 | 2.25 (1.82–2.76) | 1.12 (0.85–1.48) | 0.08 | 1.28 (0.92–1.77) | 0.04 |
| Ex-smoker | 80 | 2.37 (2.01–2.77) | 1.29 (1.02–1.62) | 1.45 (1.08–1.93) | |||
| Never smoker | 78 | 1.85 (1.53–2.23) | 1 | 1 | |||
| Spirometry | Obstructive | 13 | 3.33 (2.42–4.47) | 1.24 (0.90 1.72) | 0.22 | 1.69 (1.16–2.46) | 0.01 |
| Restrictive | 18 | 1.71 (1.11–2.50) | 0.81 (0.52–1.22) | 0.83 (0.54–1.29) | |||
| Normal | 65 | 2.07 (1.54–2.23) | 1 | 1 | |||
| Baseline MRC breathlessness score | 3–5 | 11 | 2.57 (1.63–3.86) | 1.35 (0.82–2.22) | 0.01 | ||
| 2 | 55 | 2.64 (2.17–3.17) | 1.37 (1.08–1.73) | ||||
| 1 | 135 | 1.88 (1.63–2.15) | 1 | ||||
| Recreational drug use, ever | Yes | 77 | 2.19 (1.92–2.50) | 1.22 (0.85–1.76) | 0.28 | ||
| No | 127 | 2.03 (1.68–2.42) | 1 | ||||
| Recreational drug use, last 3 months | Yes | 51 | 2.11 (1.69–2.60) | 0.92 (0.51–1.37) | 0.67 | ||
| No | 153 | 2.18 (1.93–2.46) | 1 | ||||
| Ethnicity | Black African / Caribbean | 23 | 1.61 (1.06–2.37) | 0.64 (0.42–0.96) | 0.01 | 1.07 (0.62–1.88) | 0.25 |
| South Asian / other / mixed | 13 | 3.01 (1.50–5.39) | 1.39 (0.98–2.00) | 1.40 (0.94–2.07 | |||
| White | 173 | 2.13 (1.90–2.38) | 1 | 1 | |||
| Educational attainment | Other | 20 | 2.27 (1.61–3.12) | 0.88 (0.56–1.39) | 0.91 | ||
| Degree | 116 | 2.38 (2.07–2.73) | 0.94 (0.70–1.25) | ||||
| A level | 32 | 1.89 (1.41–2.47) | 0.91 (0.63–1.31) | ||||
| None/GCSE | 40 | 1.64 (1.23–2.13) | 1 | ||||
| Baseline SGRQ | >20 | 42 | 2.72 (2.17–3.38) | 1.39 (0.68–2.24) | 0.14 | ||
| 10–20 | 28 | 2.52 (1.99–3.14) | 1.41 (0.69–2.89) | ||||
| <10 | 96 | 1.84 (1.58–2.11) | 1 | ||||
| Current CD4a | >500 | 94 | 1.98 (1.67–2.33) | 0.73 (0.37–1.42) | 0.27 | ||
| 350–500 | 27 | 1.86 (1.35–2.51) | 0.58 (0.26–1.29) | ||||
| <350 | 15 | 3.30 (2.23–4.72) | 1 | ||||
| Nadir CD4a | 500+ | 17 | 1.86 (1.19–2.76) | 0.75 (0.38–1.48) | 0.28 | ||
| 350–500 | 20 | 2.05 (1.40–2.90) | 0.84 (0.45–1.58) | ||||
| 200–350 | 36 | 1.84 (1.37–2.41) | 0.93 (0.55–1.56) | ||||
| <200 | 63 | 2.26 (1.78–2.72) | 1 | ||||
a: calculated for HIV positive participants only
b: Poisson regression