1. Respiratory Tract Diseases

According to research studies smokers run greater risk for catching acute respiratory tract infections than non-smokers, even though there is no chronic obstructive pulmonary disease (COPD) at the background. Smoking increases the risk for influenza and pneumonia over 50 % compared to non-smokers. Low-tar cigarettes cause fewer acute respiratory tract infections.

Approximately 90 % of chronic obstructive pulmonary diseases have been caused by smoking. 20-25 % of smokers catch the obstructive pulmonary disease. The amount of smoking and years of smoking are the factors that contribute to the risk of catching the disease. Because severe symptoms develop slowly, it is possible that even half of the pulmonary functions have stopped before the actual diagnosis is made.