Tuberculosis, airway obstruction, and mortality in Finland

Abstract

Introduction: Pulmonary tuberculosis (TB) is associated with chronic airway obstruction and predicts mortality. Yet, little follow-up data exist concerning the associations between these in long-term. Aims and objectives: To evaluate whether there are associations between past TB, obstruction, and mortality in 30-years´ follow-up. Methods: We analysed the survey data of 6701 Finns aged 30 or over who participated in the Mini-Finland Health Survey between 1978 and 1980, underwent spirometry, and had all the relevant health information collected. Past TB was defined either as a disease history (TB treated in hospital or with TB medications) or a scar indicating TB on chest x-ray. Obstruction was specified with the lower limit of normal (LLN), and classified for severity by Global initiative for chronic Obstructive Lung Disease (GOLD) stages 1–4. Results: Past TB was closely associated with the prevalence of obstruction after adjustment for smoking history and other potential confounders. The adjusted odds ratio of obstruction was 2.21 (95% CI 1.52–3.21) in those with a scar recorded by one of the two radiologists, 2.48 (1.63–3.78) if recorded by both radiologists, and 4.59 (2.86–7.37) in those with a disease history, as compared with subjects without TB. Among those with neither past TB nor obstruction, with past TB only, with obstruction only, and with both, the adjusted hazard ratios of subsequent mortality were 1.00 (reference), 1.13 (95% CI 1.04–1.23), 1.67 (1.34–2.08), and 1.84 (1.50–2.26), respectively. Conclusions: Past TB, and even a scar indicating it on chest x-ray, is a strong determinant of airway obstruction. Past TB and obstruction predict mortality with an additive pattern.