before they were randomly assigned to take a placebo , vitamin E supplements -LRB- 600 IU every other day -RRB- or aspirin -LRB- 100 mg per day -RRB- , either alone or in combination . At the end of 10 years , 760 of the 19,937 women who took vitamin E alone or with aspirin developed COPD compared with 846 of the 19,939 who took a placebo or aspirin alone -- a 10 percent risk reduction . Vitamin E did not lower the risk of asthma , a condition associated with a higher risk of COPD . Health.com : 10 ways to have cleaner air at home The researchers took into account factors such as cigarette smoking and age , which can affect COPD risk . The study , conducted by Cornell University and Brigham and Women 's Hospital researchers , is to be presented this week at the annual American Thoracic Society meeting in New Orleans . The idea that vitamin E can reduce the risk of developing COPD is `` biologically plausible , '' says Yvonne Kelly , Ph.D. , an associate professor in the department of epidemiology and public health at University College London . Experts believe
-LRB- Health.com -RRB- -- People who take vitamin E supplements regularly for years -- whether they are smokers or nonsmokers -- may lower their risk of chronic obstructive pulmonary disease , the lung condition that is the fourth leading cause of death in the United States . COPD includes emphysema and chronic bronchitis and is often , but not always , caused by smoking . While the risk reduction is relatively small , 10 percent , COPD is a common and life-threatening condition in which a decline in lung function can be slowed down but not reversed . COPD symptoms include shortness of breath , coughing , and fatigue . `` The effect appears to be modest . But for something for which there is n't really any effective therapy and tends to be a degenerative condition , anything that would reduce the risk even somewhat is not an insubstantial benefit , '' says Jeffrey B. Blumberg , Ph.D. , a professor of nutrition at Tufts University in Boston who was not involved in the study . The research , from the government-funded Women 's Health Study , included 39,876 women 45 years and older who were free of COPD