Table 4.
Results of univariable and multivariable logistic regression analysis for spirometric obstruction (FEV1/FVC less than lower limit of normal) *
| Variable | Univariable analysis | Multivariable analysis | ||
|---|---|---|---|---|
| OR (95% CI) | P value | aOR (95% CI) | P value | |
| Male sex | 1.31 (0.56–3.17) | 0.54 | ||
| Age, years | 1.02 (0.99–1.05 | 0.31 | ||
| BMI | 0.91 (0.83–0.99) | 0.04† | 0.88 (0.79–0.96) | 0.01† |
| Alcohol consumed | 0.67 (0.30–1.51) | 0.34 | 0.85 (0.17–4.25) | 0.07 |
| Highest level of education‡ | Linear: 0.53 (0.22–0.64) | 0.14 | ||
| Quadratic: 1.96 (0.72–6.13) | 0.21 | |||
| Cubic: 3.19 (1.04–12.71) | 0.06 | |||
| HIV status | Positive: 1.34 (0.42–4.01) | 0.61 | ||
| Unknown: 1.67 (0.31–8.12) | 0.52 | |||
| mMRC Score‡ | Linear: 1.98 (0.68–5.63) | 0.20 | ||
| Quadratic: 0.39 (0.09–1.57) | 0.17 | |||
| Cubic: 0.39 (0.09–1.37) | 0.16 | |||
| 6MWD, m | 1.00 (0.18–15.30) | 0.29 | 0.99 (0.98–1.01) | 0.91 |
| Chronic cough for at least 3 months per year | 0.92 (0.27–2.79) | 0.89 | 0.00 (0–∞) | 0.99 |
| Chronic bronchitis symptoms§ | Yes: 2.01 (0.73–5.49) | 0.17 | OR (yes): 0.00 (0.00–∞) | 0.99 |
| Unknown: 2.46 (0.28–21.46) | 0.38 | OR (unknown): 3.76 (0.34–44.05) | 0.26 | |
| Number of times treated for TB (1, 2, ≥3) | Linear: 1.98 (0.75–5.27) | 0.16 | ||
| Quadratic: 0.96 (0.42–2.24) | 0.93 | |||
| Age at first TB, years | 1.00 (0.97–1.03) | 0.87 | ||
| Ever not completed treatment | 1.59 (0.30–7.64) | 0.56 | ||
| Ever had MDR/XDR-TB | 4.30 (0.40–94.54) | 0.24 | ||
| Smoking status | Ex: 0.75 (0.10–3.77) | 0.74 | ||
| Never: 0.77 (0.30–1.89) | 0.57 | |||
| Ever smoked substance other than cigarettes | 1.79 (0.78–4.13) | 0.17 | ||
| Any prolonged (>15 h) exposure to vapours, dusts, gases or fumes at home or in job | 0.59 (0.25–1.36) | 0.21 | ||
| Final model | AIC: 128.3 | |||
| Cox–Snell R2: 0.18 | ||||
| Nagelkerke: 0.25 | ||||
* Variables were included based on exposures of interest and possible confounders. Statistically significant variables as per final backwards multivariable regression analysis. For binary variables, the other group is the comparator. No obstruction is comparator group for all ORs.
† P < 0.05.
‡ mMRC and education level treated as ordinal categorical values.
§ Defined as productive cough for at least 3 months in the previous 2 years.
FEV1 = forced expiratory volume in 1 sec; FVC = forced vital capacity; OR = odds ratio; CI = confidence interval; aOR = adjusted OR; BMI = body mass index; mMRC = modified medical research council; 6MWD = 6-min walking distance; MDR-TB = multidrug-resistant TB; XDR-TB = extensively drug-resistant TB; AIC = Akaike Information Criterion.