Chronic bronchitis (CB) is one of the most common respiratory diseases. Risk factors for developing CB include: tobacco use, airborne pollutants, occupational factors, viral infections. However, at the moment there is no accurate data regarding to what extent exactly the use of tobacco increases the risk of developing CB. Our work was aimed to quantify tobacco smoking (TS) as an individual risk factor for the development of CB and respiratory symptoms, syndromes, as well as to evaluate population attributable risk (PAR).

MATERIAL AND METHODS

The study group included 119 people (63 smokers, and 56 never-smokers), who did not have respiratory diseases and were not exposed to occupational risk factors. To establish the status of smoking and identify respiratory symptoms, a questionnaire was developed and validated, a spirometric study was conducted to assess bronchial obstruction. To analyze the effect of TS on the development of CB, the obtained parameters were compared among smokers and nonsmokers using the analysis of variance and nonparametric method of comparing medians. The relative individual risk of developing CB, respiratory symptoms (cough, sputum, dyspnea) in TS was calculated using age stratification, which eliminates interfering factors associated with age. Dose-dependent effects on the development of CB were evaluated using stratification of patients by the intensity of smoking. PAR was calculated for a tobacco 30% smoking prevalence among the adult population of the Russian Federation.

RESULTS

Risks of developing CB age adjusted (RR=10.4) and respiratory symptoms and syndromes (RR=8—10), respectively. This risk is «dose-dependent», it increases from 5.8 to 32.73 with increasing smoking intensity from 10 pack-year to more than 21; for respiratory symptoms development it increases from 7.8—15.7 to 32.4—62.7. In smokers, a statistically significant decrease in bronchial patency and a 2-fold increase in the annual frequency of colds were revealed. PAR made 0.74, due to the high individual risk of the CB development.

CONCLUSION

Smoking of tobacco is a strong risk factor for developing CB, respiratory symptoms (cough, phlegm, dyspnoe) and respiratory syndromes (bronchial obstruction). It was revealed that in the Russian Federation 74% of all cases of the CB development are associated with the tobacco smoking.