Acid reflux can cause respiratory symptoms and changes in the lung, particularly related to asthma rather than COPD. However, having a single test will not give you the answer to your question. The PFT has to be performed before and after an inhaled bronchodilator to give you an idea as to the acute affects of the reflux. Since you have not mentioned how many and for how long you smoked, it is also not possible to really give you a good idea of if the smoking caused the low test scores. You need the additional testing and may want to see a pulmonologist.