If you smoke or have passive smoke (and even if you don't) please get tested for Alpha 1 Antitrypsin deficency. All you need to do is have an ordinary blood test at your doctors. If you have Alpha-1 deficiency then you can have further tests to see how it effects you.
If you have this genetic condition and smoke/passive smoke the effects of lung damage can happen earlier. Also you can stop smoking and stop some damage happening to your lungs. If you have liver damage you can also take action to help yourself.
There is no cure for Alpha-1 so anything you can do to help yourself slows down the damage.